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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title><![CDATA[KOST]]></title>
<subtitle><![CDATA[Do not ship shits.]]></subtitle>
<link href="/atom.xml" rel="self"/>
<link href="http://jinyudong.com/"/>
<updated>2015-03-10T04:57:42.215Z</updated>
<id>http://jinyudong.com/</id>
<author>
<name><![CDATA[Jin Yudong]]></name>
<email><![CDATA[kost@outlook.com]]></email>
</author>
<generator uri="http://zespia.tw/hexo/">Hexo</generator>
<entry>
<title><![CDATA[Android作品集]]></title>
<link href="http://jinyudong.com/2015/03/09/works/"/>
<id>http://jinyudong.com/2015/03/09/works/</id>
<published>2015-03-09T04:03:28.000Z</published>
<updated>2015-03-10T04:55:45.000Z</updated>
<content type="html"><![CDATA[<hr>
<p>从2012年开始学习开发Android应用，到现在已经上线了七八款应用。对于应用的开发流程、优化等也有一定的了解，大部分都是独立设计界面与开发编码的，下面选一些比较有代表性的作品进行简单的展示介绍。</p>
<h1 id="弹窗信息">弹窗信息</h1>
<p>这个一个跟同学两个人合作做的作品，其中我承担了大部分手机端功能的开发，同时也独自负责了服务器端的开发（使用简单的PHP语言与MySQL数据库）。这是一款让你在Android设备上拥有ios通知功能的软件，除此之外还有很多个性化设置，在功能和体验上更加完善。在各大市场均可下载。</p>
<p>下载量：<strong>500万次（免费付费各大市场总和）</strong></p>
<p>累计用户：<strong>70万人（按独立设备统计）</strong></p>
<p>日弹窗量：<strong>200万次</strong></p>
<p>荣耀达成：<strong>魅族软件中心首页推荐、付费排行榜第一名</strong></p>
<p>技术创新：</p>
<ol>
<li>仿照系统源码重新开发设置界面(K-PreferencScreen)，使其更加灵活多变；</li>
<li>主题切换功能（包括皮肤、自定义颜色等等）；</li>
<li>可视化投票模块（使用RecyclerView等），让用户可以发布自己的投票表达意见。</li>
</ol>
<p>部分截图如下：</p>
<p><img src="http://sinacloud.net/kost-works/pics/popup.jpg" alt=""></p>
<h1 id="魅手机隐私锁">魅手机隐私锁</h1>
<p>是一款独立设计与开发的手机锁定软件，可以锁定App与文件等。七大锁定模式：九宫格锁定模式、手势锁定模式、密码锁定模式、程序假死锁定模式、提示锁定模式、不执行模式、程序跳转模式。每个模式的作用具体是什么还需要您自己来体会。文件隐藏：不仅仅可以隐藏android系统下面的文件，而且当手机作为u盘连接到windows电脑上面时，文件也会被隐藏的天衣无缝。</p>
<p>下载量：<strong>12万次（魅族市场收费版）</strong></p>
<p>荣耀达成：<strong>魅族软件中心首页推荐、付费排行榜第一名</strong></p>
<p>技术难点：</p>
<ol>
<li>防止用户破解，保证锁定的坚固有效；</li>
<li>密码等隐私信息的存储；</li>
</ol>
<p>截图如下：</p>
<p><img src="http://sinacloud.net/kost-works/pics/lock.jpg" alt=""></p>
<h1 id="计划派">计划派</h1>
<p>如果你正被每天琐碎的种种急得焦头烂额，如果你曾因为忘了准备礼物而让TA生气，如果你渴望把一切打理的井井有条，那么“计划派”正是你的不二选择！她将为你提供：最简单易用的计划管理列表；最轻松自如的交互操作；最简洁大方的用户界面。她让繁杂的事物变得亲切有序，让远大的目标变得真实可企及。</p>
<p>下载量：<strong>5万次</strong></p>
<p>荣耀达成：<strong>魅族软件中心首页推荐</strong></p>
<p>技术难点：</p>
<ol>
<li>列表的拖动与排序功能；</li>
<li>自定义时间Picker的效率优化与时间展示问题。</li>
</ol>
<p>截图如下：</p>
<p><img src="http://sinacloud.net/kost-works/pics/jihuapai.jpg" alt=""></p>
<h1 id="夜间模式">夜间模式</h1>
<p>你是否有晚上玩手机的习惯？是否觉得最小亮度还是刺眼？《夜间模式》可帮您将亮度降到更低！保护您的双眼！并具备手电筒功能哦~</p>
<p>下载量：<strong>16万次（魅族市场收费版）</strong></p>
<p>荣耀达成：<strong>魅族软件中心首页推荐</strong></p>
<p>技术实现：本软件实现较为简单，使用WindowManager创建覆盖整个屏幕的悬浮窗即可。仅使用了两天开发的时间，但是还取得了比较好的销量，着实比较意外。</p>
<p>截图如下：</p>
<p><img src="http://sinacloud.net/kost-works/pics/night.jpg" alt=""></p>
<h1 id="大象框">大象框</h1>
<p>大象框是赵云科技的一款新产品，简单来说是一个云电子相框，可以通过手机向异地的长辈传送照片，免去让他们操作复杂手机的烦恼。我在其中独自负责相框端软件的开发。</p>
<p>官方网站：<a href="http://www.zhaoyuntech.com" target="_blank" rel="external">大象框</a></p>
<p>技术难点：</p>
<ol>
<li>低端平板上大量高清图片的展示与存储（需要良好的内存管理避免OOM）；</li>
<li>低端平板上交互的重构与流畅度优化。</li>
</ol>
]]></content>
<summary type="html">
<![CDATA[<hr>
<p>从2012年开始学习开发Android应用，到现在已经上线了七八款应用。对于应用的开发流程、优化等也有一定的了解，大部分都是独立设计界面与开发编码的，下面选一些比较有代表性的作品进行简单的展示介绍。</p>
<h1 id="弹窗信息">弹窗信息</h1>
<p>这]]>
</summary>
</entry>
<entry>
<title><![CDATA[庖丁解牛之Volley篇(一) - 简单介绍与使用方法]]></title>
<link href="http://jinyudong.com/2014/12/22/Volley-1/"/>
<id>http://jinyudong.com/2014/12/22/Volley-1/</id>
<published>2014-12-22T13:17:06.000Z</published>
<updated>2014-12-23T07:55:26.000Z</updated>
<content type="html"><![CDATA[<blockquote>
<p><em>笔者小菜，文中可能会有一些误解或者错误的地方，欢迎指出交流</em></p>
</blockquote>
<h2 id="什么是Volley">什么是Volley</h2>
<p>Volley是google在2013年IO大会上推出的一个轻量级HTTP库，可以让Android上面的网络操作的构建变得异常简单，而且响应更加迅速。据说google内部测试了很多种HTTP库，Volley在每一项测试中都取得了最好的成绩。真假不知道，但是这个开源库的内部实现肯定会引起程序猿的兴趣，它内部是如何实现的呢？我们能从这个开源库里面学到一些什么东西呢？这就是接下来一系列的博文给大家讲述的内容。</p>
<a id="more"></a>
<blockquote>
<p>本文中的内容基本来自于Google的<a href="http://developer.android.com/training/volley/index.html" target="_blank" rel="external">官方文档</a>，如果熟悉Volley的使用方法，可以跳过本文章。</p>
</blockquote>
<p>Volley的优势有以下几点：</p>
<ul>
<li>网络请求的队列化、自动化处理</li>
<li>多网络连接并发</li>
<li>使用文件和内存Cache机制实现HTTP的快速响应</li>
<li>支持网络请求的自定义优先级</li>
<li>网络请求的取消功能，可以对指定范围或指定种类的网络请求进行取消</li>
<li>傻瓜式自定义，如可以自定义重试策略</li>
<li>数据显示与网络请求的异步</li>
<li>强大的跟踪与调试工具</li>
</ul>
<p>优点说了这么多，到底是如何做到的呢？别着急，了解内部实现之前，先来了解一下Volley的简单用法。</p>
<h2 id="Volley的简单使用方法">Volley的简单使用方法</h2>
<h3 id="发送请求">发送请求</h3>
<p>使用Volley时，需要创建一个RequestQueue，并将Request传递给它。RequestQueue管理后台工作线程获取网络内容、读写Cache、解析Response。Request负责解析获取到的网络数据，Volley负责将解析后的结果在主线程进行分发。下面是一个简单的例子，从网络获取字符串：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div></pre></td><td class="code"><pre><div class="line">RequestQueue queue = Volley.newRequestQueue(<span class="keyword">this</span>);</div><div class="line">String url =<span class="string">"http://www.google.com"</span>;</div><div class="line"><span class="comment">// Request a string response from the provided URL.</span></div><div class="line">StringRequest stringRequest = <span class="keyword">new</span> StringRequest(Request.Method.GET, url,</div><div class="line"> <span class="keyword">new</span> Response.Listener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onResponse</span>(String response) {</div><div class="line"> <span class="comment">// Display the first 500 characters of the response string.</span></div><div class="line"> mTextView.setText(<span class="string">"Response is: "</span>+ response.substring(<span class="number">0</span>,<span class="number">500</span>));</div><div class="line"> }</div><div class="line">}, <span class="keyword">new</span> Response.ErrorListener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onErrorResponse</span>(VolleyError error) {</div><div class="line"> mTextView.setText(<span class="string">"That didn't work!"</span>);</div><div class="line"> }</div><div class="line">});</div><div class="line"><span class="comment">// Add the request to the RequestQueue.</span></div><div class="line">queue.add(stringRequest);</div></pre></td></tr></table></figure>
<p>首先使用<em>Volley.newRequestQueue(this)</em>来创建一个请求队列，然后创建一个Request，并将这个Request添加到请求队列当中。在这个例子中，StringRequest是Request的具体的一个实现，还有很多种其他类型的Request，并可以编写自己的Request。当添加到队列之后，Volley会自动开始处理队列中的Request（通过<em>PriorityBlockingQueue</em>进行实现），处理结果通过上面所示的<em>Response.Listener</em>与<em>Response.ErrorListener</em>来进行返回。值得注意的是，Volley都在主线程进行结果的返回，你可以直接在listener中进行UI的控制操作。</p>
<h3 id="取消请求">取消请求</h3>
<p>Volley的取消网络异常简单方便，一旦Request被取消掉，Volley就不会对listener进行调用。实际中利用到取消请求的情况非常多，在一个activity结束的时候，我们通常会在onStop方法中处理一些没有被反馈的网络请求，并且在listener中判断当前Activity是否存在: <em>getActivity() == null</em>或<em>onSaveInstanceState()</em>是否被调用。而在Volley中，并不需要这些繁琐的判断操作：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">final</span> String TAG = <span class="string">"MyTag"</span>;</div><div class="line">StringRequest stringRequest;</div><div class="line">RequestQueue mRequestQueue;</div><div class="line">stringRequest.setTag(TAG);<span class="comment">//或将此Activity(Context)传入也可以</span></div><div class="line">mRequestQueue.add(stringRequest);</div></pre></td></tr></table></figure>
<p>在上面的代码中，我们对Request设置Tag，这个Tag可以是任何类型，可以是当前的Activity，可以是一个字符串，相同Tag的Request表示他们是同一个类型的Request，并可以进行批量的取消：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line"><span class="annotation">@Override</span></div><div class="line"><span class="keyword">protected</span> <span class="keyword">void</span> <span class="title">onStop</span> () {</div><div class="line"> <span class="keyword">super</span>.onStop();</div><div class="line"> <span class="keyword">if</span> (mRequestQueue != <span class="keyword">null</span>) {</div><div class="line"> mRequestQueue.cancelAll(TAG);</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
<h2 id="配置RequestQueue请求队列">配置RequestQueue请求队列</h2>
<p>上面介绍了Volley的最基本的使用方法，本节将介绍如何自定义RequestQueue的配置，让它更适用于你自己的应用程序。</p>
<h3 id="配置RequestQueue">配置RequestQueue</h3>
<p>RequestQueue工作过程中，需要两件东西：</p>
<ul>
<li>网络请求实现（HttpURLConnection or AndroidHttpClient or ANYHING ELSE）</li>
<li>缓存空间来对网络请求进行缓存</li>
</ul>
<p>关于网络请求实现需要特别说一下，Volley对不同的Android版本提供了不同的网络请求实现，在低于API Level 9 (Gingerbread)的情况下，使用<a href="http://developer.android.com/reference/android/net/http/AndroidHttpClient.html" target="_blank" rel="external">AndroidHttpClient</a>。当高于API Level 9的时候，使用<a href="http://developer.android.com/reference/java/net/HttpURLConnection.html" target="_blank" rel="external">HttpURLConnection</a>。关于为何这么做，可以参考<a href="http://android-developers.blogspot.com/2011/09/androids-http-clients.html" target="_blank" rel="external">这里</a>，当然你也可以使用自己的网络请求实现。</p>
<p>如下的代码展示了如何对RequestQueue进行配置：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div></pre></td><td class="code"><pre><div class="line">RequestQueue mRequestQueue;</div><div class="line"><span class="comment">//初始化Cache空间，可指定大小与地址</span></div><div class="line">Cache cache = <span class="keyword">new</span> DiskBasedCache(getCacheDir(), <span class="number">1024</span> * <span class="number">1024</span>); <span class="comment">// 1MB</span></div><div class="line"><span class="comment">//使用HttpURLConnection作为网络请求实现,若要用AndroidHttpClient，可以使用HttpClientStack</span></div><div class="line">Network network = <span class="keyword">new</span> BasicNetwork(<span class="keyword">new</span> HurlStack());</div><div class="line"><span class="comment">//使用Cache和Network对请求队列进行初始化</span></div><div class="line">mRequestQueue = <span class="keyword">new</span> RequestQueue(cache, network);</div><div class="line">mRequestQueue.start();</div><div class="line">String url =<span class="string">"http://www.myurl.com"</span>;</div><div class="line">StringRequest stringRequest = <span class="keyword">new</span> StringRequest(Request.Method.GET, url,</div><div class="line"> <span class="keyword">new</span> Response.Listener<String>() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onResponse</span>(String response) {</div><div class="line"> <span class="comment">//处理结果</span></div><div class="line"> }</div><div class="line">},</div><div class="line"> <span class="keyword">new</span> Response.ErrorListener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onErrorResponse</span>(VolleyError error) {</div><div class="line"> <span class="comment">//处理错误</span></div><div class="line"> }</div><div class="line">});</div><div class="line"><span class="comment">//将请求添加到队列当中</span></div><div class="line">mRequestQueue.add(stringRequest);</div></pre></td></tr></table></figure>
<h3 id="使用单例模式">使用单例模式</h3>
<p>在RequestQueue的使用中，你可以随时调用<em>Volley.newRequestQueue()</em>来创建一个请求队列，如果不再想使用此队列了，直接调用stop函数即可。这样做无可厚非，但是一个更有趣的做法是保持一个单例，在整个程序运行的过程中维持这个RequestQueue单例。从易于管理与效率方面，这么做会更好一些。当然还是具体情况具体分析，看哪种使用发放更适合你的使用场景。如果你对单例模式不太了解，可以参见<a href="http://en.wikipedia.org/wiki/Singleton_pattern" target="_blank" rel="external">这里</a>。</p>
<p>我们在Application.onCreate()中创建这个单例，值得注意的是，传给RequesQueue的Context需要是Application的Context，而不是Activity的Context。放码：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> MySingleton {</div><div class="line"> <span class="keyword">private</span> <span class="keyword">static</span> MySingleton mInstance;</div><div class="line"> <span class="keyword">private</span> RequestQueue mRequestQueue;</div><div class="line"> <span class="keyword">private</span> ImageLoader mImageLoader;</div><div class="line"> <span class="keyword">private</span> <span class="keyword">static</span> Context mCtx;</div><div class="line"> <span class="keyword">private</span> <span class="title">MySingleton</span>(Context context) {</div><div class="line"> mCtx = context;</div><div class="line"> mRequestQueue = getRequestQueue();</div><div class="line"> mImageLoader = <span class="keyword">new</span> ImageLoader(mRequestQueue,</div><div class="line"> <span class="keyword">new</span> ImageLoader.ImageCache() {</div><div class="line"> <span class="keyword">private</span> <span class="keyword">final</span> LruCache<String, Bitmap></div><div class="line"> cache = <span class="keyword">new</span> LruCache<String, Bitmap>(<span class="number">20</span>);</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> Bitmap <span class="title">getBitmap</span>(String url) {</div><div class="line"> <span class="keyword">return</span> cache.get(url);</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">putBitmap</span>(String url, Bitmap bitmap) {</div><div class="line"> cache.put(url, bitmap);</div><div class="line"> }</div><div class="line"> });</div><div class="line"> }</div><div class="line"> <span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">synchronized</span> MySingleton <span class="title">getInstance</span>(Context context) {</div><div class="line"> <span class="keyword">if</span> (mInstance == <span class="keyword">null</span>) {</div><div class="line"> mInstance = <span class="keyword">new</span> MySingleton(context);</div><div class="line"> }</div><div class="line"> <span class="keyword">return</span> mInstance;</div><div class="line"> }</div><div class="line"> <span class="keyword">public</span> RequestQueue <span class="title">getRequestQueue</span>() {</div><div class="line"> <span class="keyword">if</span> (mRequestQueue == <span class="keyword">null</span>) {</div><div class="line"> <span class="comment">// getApplicationContext() is key, it keeps you from leaking the</span></div><div class="line"> <span class="comment">// Activity or BroadcastReceiver if someone passes one in.</span></div><div class="line"> mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());</div><div class="line"> }</div><div class="line"> <span class="keyword">return</span> mRequestQueue;</div><div class="line"> }</div><div class="line"> <span class="keyword">public</span> <T> <span class="keyword">void</span> <span class="title">addToRequestQueue</span>(Request<T> req) {</div><div class="line"> getRequestQueue().add(req);</div><div class="line"> }</div><div class="line"> <span class="keyword">public</span> ImageLoader <span class="title">getImageLoader</span>() {</div><div class="line"> <span class="keyword">return</span> mImageLoader;</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
<p>写好这个单例模式之后，使用方法就变得异常简单，你可以在不同的Activity中使用如下代码，它们使用的都会是同一个RequestQueue：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div></pre></td><td class="code"><pre><div class="line"><span class="comment">//获取RequestQueue</span></div><div class="line">RequestQueue queue = MySingleton.getInstance(<span class="keyword">this</span>.getApplicationContext()).</div><div class="line"> getRequestQueue();</div><div class="line">...</div><div class="line"><span class="comment">//添加一个Request到RequestQueue中</span></div><div class="line">MySingleton.getInstance(<span class="keyword">this</span>).addToRequestQueue(stringRequest);</div></pre></td></tr></table></figure>
<p>需要注意的是，使用单例模式之后所有的网络请求都将插入到这个队列当中，因此我们在不同的界面中进行跳转的时候，需要注意对一些Request的优先级进行提高，或者是取消一些Request，让当前界面的Request更快速的进行响应。关于Request的取消在上面已经讲过了，这里不再赘述。</p>
<h2 id="图片的网络请求">图片的网络请求</h2>
<p>请求图片对于Android应用来说是一个很重要的功能，看上去简单，其实涉及到很多复杂的东西。比如图片的解析，内存的管理，不同设备下的优化等等。Volley对于网络图片支持方面虽然比不上Picasso或UniversalImageLoader等工具，但是在某些场景下，也足够使用了。在这里讲一下使用Volley对图片进行网络请求。</p>
<p>在Volley中关于图片请求功能部分，提供了三个类：</p>
<p><strong>ImageRequest</strong>：与StringRequest相同，它继承了Request类，实现了对指定URL的图片进行解码，并将解码后的图片按照规定的大小进行返回。它的牛逼之处是对图片解析和处理的操作都是在后台工作线程进行，不会影响主线程的操作，等到图片处理完毕，再交给主线程进行处理。</p>
<p><strong>ImageLoader</strong>：它提供了对远程网络图片的缓存功能，牛逼之处是在内存中开辟了一块缓存图片的空间，在进行网络加载时，可以对已加载过的图片从Cache中获取。</p>
<p><strong>NetworkImageView</strong>：这个更进一步，直接提供了一个加载图片的控件，它其实也是继承了ImageView，使用起来更加方便。牛逼的地方是，当这个View不再显示的时候或被销毁后它会对正在进行的图片Request进行取消，不浪费带宽和CPU资源，屌吗？</p>
<h3 id="使用ImageRequest">使用ImageRequest</h3>
<p>使用ImageRequest的方法与使用其他Request的方法大同小异，直接放码：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div></pre></td><td class="code"><pre><div class="line">ImageView mImageView;</div><div class="line">String url = <span class="string">"http://i.imgur.com/7spzG.png"</span>;</div><div class="line">mImageView = (ImageView) findViewById(R.id.myImage);</div><div class="line">...</div><div class="line"><span class="comment">//根据URL获取Bitmap，并展示到界面上</span></div><div class="line">ImageRequest request = <span class="keyword">new</span> ImageRequest(url,</div><div class="line"> <span class="keyword">new</span> Response.Listener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onResponse</span>(Bitmap bitmap) {</div><div class="line"> mImageView.setImageBitmap(bitmap);</div><div class="line"> }</div><div class="line"> }, <span class="number">0</span>, <span class="number">0</span>, <span class="keyword">null</span>,</div><div class="line"> <span class="keyword">new</span> Response.ErrorListener() {</div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onErrorResponse</span>(VolleyError error) {</div><div class="line"> mImageView.setImageResource(R.drawable.image_load_error);</div><div class="line"> }</div><div class="line"> });</div><div class="line"><span class="comment">//添加到单例队列</span></div><div class="line">MySingleton.getInstance(<span class="keyword">this</span>).addToRequestQueue(request);</div></pre></td></tr></table></figure>
<h3 id="使用ImageLoader和NetworkImageView">使用ImageLoader和NetworkImageView</h3>
<h4 id="ImageLoader的使用">ImageLoader的使用</h4>
<p>Imageloader的使用代码如下，我们从之前的那个单例中，可以获取一个ImageLoader实例，使用这个ImageLoader来进行图片的加载。同样，在使用单例的时候，也要注意图片请求的优先级、取消等等。执行了get函数之后，当图片从网络获取完毕，会自动加载：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line">ImageLoader mImageLoader;</div><div class="line">ImageView mImageView;</div><div class="line"><span class="comment">//请求的图片地址</span></div><div class="line"><span class="keyword">private</span> <span class="keyword">static</span> <span class="keyword">final</span> String IMAGE_URL =</div><div class="line"> <span class="string">"http://developer.android.com/images/training/system-ui.png"</span>;</div><div class="line">...</div><div class="line">mImageView = (ImageView) findViewById(R.id.regularImageView);</div><div class="line"><span class="comment">//获取单例中的Imageloader</span></div><div class="line">mImageLoader = MySingleton.getInstance(<span class="keyword">this</span>).getImageLoader();</div><div class="line"><span class="comment">//指定URL、默认图片、加载失败图片</span></div><div class="line">mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,</div><div class="line"> R.drawable.def_image, R.drawable.err_image));</div></pre></td></tr></table></figure>
<h4 id="NetworkImageView的使用">NetworkImageView的使用</h4>
<p>由于NetworkImageView是继承自ImageView的，所以基本用法一致，就多了一些网络请求的包装。在XML布局文件中声明布局如下：</p>
<figure class="highlight xml"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="tag"><<span class="title">com.android.volley.toolbox.NetworkImageView</span></span></div><div class="line"> <span class="attribute">android:id</span>=<span class="value">"@+id/networkImageView"</span></div><div class="line"> <span class="attribute">android:layout_width</span>=<span class="value">"150dp"</span></div><div class="line"> <span class="attribute">android:layout_height</span>=<span class="value">"170dp"</span></div><div class="line"> <span class="attribute">android:layout_centerHorizontal</span>=<span class="value">"true"</span> /></div></pre></td></tr></table></figure>
<p>使用NetworkImageView的时候，也需要指定一个ImageLoader实例。当图片从网络获取完毕，会自动加载到NetworkImageView上面：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">ImageLoader mImageLoader;</div><div class="line">NetworkImageView mNetworkImageView;</div><div class="line"><span class="keyword">private</span> <span class="keyword">static</span> <span class="keyword">final</span> String IMAGE_URL =</div><div class="line"> <span class="string">"http://developer.android.com/images/training/system-ui.png"</span>;</div><div class="line">mNetworkImageView = (NetworkImageView) findViewById(R.id.networkImageView);</div><div class="line"><span class="comment">//获取ImageLoader单例</span></div><div class="line">mImageLoader = MySingleton.getInstance(<span class="keyword">this</span>).getImageLoader();</div><div class="line"><span class="comment">//指定图片URL与用来执行网络请求的ImageLoader</span></div><div class="line">mNetworkImageView.setImageUrl(IMAGE_URL, mImageLoader);</div></pre></td></tr></table></figure>
<p>值得注意的是这里的单例模式，使用单例模式的一个好处是，这个单例的存活时间将比ctivity的存活周期更长。如果在Activity内部创建ImageLoader，当Activity旋转的时候，所有实例、图片都要重新初始化加载一遍，造成界面的闪烁。显然浪费了网络和计算资源。而独立于Activity的Imageloader中的缓存机制，可以缓存图片到内存中，当下一次再次请求这个同样的URL的时候，如果Cache命中的话，就直接从Cache加载图片，而不再从网络中加载。</p>
<h4 id="LRU_Cache">LRU Cache</h4>
<p>在Volley的toolbox中，提供了基于磁盘的缓存类<em>DiskBasedCache</em>，这个类会将缓存直接存储到指定的文件夹中。但是对于ImageLoader来说，我们必须提供一个建立在内存缓存基础上面的LRU Cache。我们可以实现<em>ImageLoader.ImageCache</em>接口来自定义一个Cache。</p>
<p>下面的代码继承了<a href="http://developer.android.com/reference/android/support/v4/util/LruCache.html" target="_blank" rel="external"><em>LruCache</em></a>类，并实现了ImageLoader.ImageCache接口。</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">import</span> android.graphics.Bitmap;</div><div class="line"><span class="keyword">import</span> android.support.v4.util.LruCache;</div><div class="line"><span class="keyword">import</span> android.util.DisplayMetrics;</div><div class="line"><span class="keyword">import</span> com.android.volley.toolbox.ImageLoader.ImageCache;</div><div class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">LruBitmapCache</span> <span class="keyword">extends</span> <span class="title">LruCache</span><<span class="title">String</span>, <span class="title">Bitmap</span>></span></div><div class="line"> <span class="keyword">implements</span> <span class="title">ImageCache</span> {</div><div class="line"> <span class="comment">//可以指定缓冲区的大小</span></div><div class="line"> <span class="keyword">public</span> <span class="title">LruBitmapCache</span>(<span class="keyword">int</span> maxSize) {</div><div class="line"> <span class="keyword">super</span>(maxSize);</div><div class="line"> }</div><div class="line"> <span class="keyword">public</span> <span class="title">LruBitmapCache</span>(Context ctx) {</div><div class="line"> <span class="keyword">this</span>(getCacheSize(ctx));</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">protected</span> <span class="keyword">int</span> <span class="title">sizeOf</span>(String key, Bitmap value) {</div><div class="line"> <span class="keyword">return</span> value.getRowBytes() * value.getHeight();</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> Bitmap <span class="title">getBitmap</span>(String url) {</div><div class="line"> <span class="keyword">return</span> get(url);</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">putBitmap</span>(String url, Bitmap bitmap) {</div><div class="line"> put(url, bitmap);</div><div class="line"> }</div><div class="line"> <span class="comment">//根据屏幕的大小来动态调节缓存区的大小，屌</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">int</span> <span class="title">getCacheSize</span>(Context ctx) {</div><div class="line"> <span class="keyword">final</span> DisplayMetrics displayMetrics = ctx.getResources().</div><div class="line"> getDisplayMetrics();</div><div class="line"> <span class="keyword">final</span> <span class="keyword">int</span> screenWidth = displayMetrics.widthPixels;</div><div class="line"> <span class="keyword">final</span> <span class="keyword">int</span> screenHeight = displayMetrics.heightPixels;</div><div class="line"> <span class="comment">// 4 bytes per pixel</span></div><div class="line"> <span class="keyword">final</span> <span class="keyword">int</span> screenBytes = screenWidth * screenHeight * <span class="number">4</span>;</div><div class="line"> <span class="keyword">return</span> screenBytes * <span class="number">3</span>;</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
<p>如果ImageLoader使用这个Cache的话：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line">RequestQueue mRequestQueue;</div><div class="line">ImageLoader mImageLoader = <span class="keyword">new</span> ImageLoader(mRequestQueue, <span class="keyword">new</span> LruBitmapCache(</div><div class="line"> LruBitmapCache.getCacheSize()));</div></pre></td></tr></table></figure>
<p>这里面非常好玩的地方是一个静态函数<em>getCacheSize</em>，它根据屏幕的分辨率大小动态调整缓冲区的大小。低端机的分辨率、内存都小一些，所以它的缓冲区也相应的小。这种做法确实很有意思。</p>
<h2 id="JSON的网络请求">JSON的网络请求</h2>
<p>这部分其实没啥好说的，基本上所有的Request用法都是一致的。Volley中对Json提供了两种类：</p>
<ul>
<li><strong>JsonArrayRequest</strong>：用来获取<a href="http://developer.android.com/reference/org/json/JSONArray.html" target="_blank" rel="external">JSONArray</a></li>
<li><strong>JsonObjectRequest</strong>：用来获取<a href="http://developer.android.com/reference/org/json/JSONObject.html" target="_blank" rel="external">JSONObject</a></li>
</ul>
<p>这两个类都是基于JsonRequest类来实现的，下面贴一个简单的代码：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div></pre></td><td class="code"><pre><div class="line">TextView mTxtDisplay;</div><div class="line">ImageView mImageView;</div><div class="line">mTxtDisplay = (TextView) findViewById(R.id.txtDisplay);</div><div class="line">String url = <span class="string">"http://my-json-feed"</span>;</div><div class="line">JsonObjectRequest jsObjRequest = <span class="keyword">new</span> JsonObjectRequest</div><div class="line"> (Request.Method.GET, url, <span class="keyword">null</span>, <span class="keyword">new</span> Response.Listener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onResponse</span>(JSONObject response) {</div><div class="line"> mTxtDisplay.setText(<span class="string">"Response: "</span> + response.toString());</div><div class="line"> }</div><div class="line">}, <span class="keyword">new</span> Response.ErrorListener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onErrorResponse</span>(VolleyError error) {</div><div class="line"> <span class="comment">// TODO Auto-generated method stub</span></div><div class="line"> }</div><div class="line">});</div><div class="line">MySingleton.getInstance(<span class="keyword">this</span>).addToRequestQueue(jsObjRequest);</div></pre></td></tr></table></figure>
<h2 id="自定义Request请求">自定义Request请求</h2>
<p>Volley的灵活性在于你可以自定义非常多的东西，而且非常简单。Volley中提供了StringRequest、ImageRequest、JsonObjectRequest等等Request类，当然我们也可以自己实现一个Request类，来适应项目的需求。创建一个自定义的Request只需要两步：</p>
<ul>
<li>继承Request<t>类，其中<t>代表了你从网络获取的相应中需要解析出来的结果。比如获取一个String字符串，你就需要继承Request<string>。</string></t></t></li>
<li>实现抽象方法<em>parseNetworkResponse()</em>和<em>deliverResponse()</em>这两个函数。</li>
</ul>
<h3 id="parseNetworkResponse">parseNetworkResponse</h3>
<p>一个Response中包含了被解析过的对象，如Json、String、Bitmap等等。下面是一个简单的parseNetworkResponse实现：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div></pre></td><td class="code"><pre><div class="line"><span class="annotation">@Override</span></div><div class="line"><span class="keyword">protected</span> Response<T> <span class="title">parseNetworkResponse</span>(</div><div class="line"> NetworkResponse response) {</div><div class="line"> <span class="keyword">try</span> {</div><div class="line"> String json = <span class="keyword">new</span> String(response.data,</div><div class="line"> HttpHeaderParser.parseCharset(response.headers));</div><div class="line"> <span class="keyword">return</span> Response.success(gson.fromJson(json, clazz),</div><div class="line"> HttpHeaderParser.parseCacheHeaders(response));</div><div class="line"> }</div><div class="line"> <span class="comment">// handle errors</span></div><div class="line">...</div><div class="line">}</div></pre></td></tr></table></figure>
<p>在这里需要注意两点：</p>
<ul>
<li><em>parseNetworkResponse</em>的传入参数是<em>NetworkResponse</em>，它包含了HTTP响应报文的负载(byte[]形式)、HTTP的Status Code还有一些响应Headers。</li>
<li>你必须返回一个Response<t>。它包含了你解析后的实例类型(<t>)，还有cache的元数据或错误信息。</t></t></li>
</ul>
<p>一般情况下都可以用如下代码来返回：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">return</span> Response.success(myDecodedObject,</div><div class="line"> HttpHeaderParser.parseCacheHeaders(response));</div></pre></td></tr></table></figure>
<p>其中Response.success()和Response.error()的内部实现如下所示：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line"><span class="javadoc">/** Returns a successful response containing the parsed result. */</span></div><div class="line"><span class="keyword">public</span> <span class="keyword">static</span> <T> Response<T> <span class="title">success</span>(T result, Cache.Entry cacheEntry) {</div><div class="line"> <span class="keyword">return</span> <span class="keyword">new</span> Response<T>(result, cacheEntry);</div><div class="line">}</div><div class="line"><span class="javadoc">/**</span></div><div class="line">* Returns a failed response containing the given error code and an optional</div><div class="line">* localized message displayed to the user.</div><div class="line">*/</div><div class="line"><span class="keyword">public</span> <span class="keyword">static</span> <T> Response<T> <span class="title">error</span>(VolleyError error) {</div><div class="line"> <span class="keyword">return</span> <span class="keyword">new</span> Response<T>(error);</div><div class="line">}</div></pre></td></tr></table></figure>
<h3 id="deliverResponse">deliverResponse</h3>
<p>Volley将处理结果在主线程进行返回，返回的实例就是你在<em>parseNetworkResponse()</em>中返回的东西。</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">protected</span> <span class="keyword">void</span> <span class="title">deliverResponse</span>(T response) {</div><div class="line"> listener.onResponse(response);</div></pre></td></tr></table></figure>
<h3 id="实例：实现GsonRequest">实例：实现GsonRequest</h3>
<p>Gson是一个可以将java对象和JSON相互转换的工具，它利用了java的反射机制。关于Gson的使用方法，参见<a href="http://code.google.com/p/google-gson/" target="_blank" rel="external">这里</a>。</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div><div class="line">33</div><div class="line">34</div><div class="line">35</div><div class="line">36</div><div class="line">37</div><div class="line">38</div><div class="line">39</div><div class="line">40</div><div class="line">41</div><div class="line">42</div><div class="line">43</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">GsonRequest</span><<span class="title">T</span>> <span class="keyword">extends</span> <span class="title">Request</span><<span class="title">T</span>> </span>{</div><div class="line"> <span class="keyword">private</span> <span class="keyword">final</span> Gson gson = <span class="keyword">new</span> Gson();</div><div class="line"> <span class="keyword">private</span> <span class="keyword">final</span> Class<T> clazz;</div><div class="line"> <span class="keyword">private</span> <span class="keyword">final</span> Map<String, String> headers;</div><div class="line"> <span class="keyword">private</span> <span class="keyword">final</span> Listener<T> listener;</div><div class="line"> <span class="javadoc">/**</span></div><div class="line"> * Make a GET request and return a parsed object from JSON.</div><div class="line"> *</div><div class="line"> *<span class="javadoctag"> @param</span> url URL of the request to make</div><div class="line"> *<span class="javadoctag"> @param</span> clazz Relevant class object, for Gson's reflection</div><div class="line"> *<span class="javadoctag"> @param</span> headers Map of request headers</div><div class="line"> */</div><div class="line"> <span class="keyword">public</span> <span class="title">GsonRequest</span>(String url, Class<T> clazz, Map<String, String> headers,</div><div class="line"> Listener<T> listener, ErrorListener errorListener) {</div><div class="line"> <span class="keyword">super</span>(Method.GET, url, errorListener);</div><div class="line"> <span class="keyword">this</span>.clazz = clazz;</div><div class="line"> <span class="keyword">this</span>.headers = headers;</div><div class="line"> <span class="keyword">this</span>.listener = listener;</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> Map<String, String> <span class="title">getHeaders</span>() <span class="keyword">throws</span> AuthFailureError {</div><div class="line"> <span class="keyword">return</span> headers != <span class="keyword">null</span> ? headers : <span class="keyword">super</span>.getHeaders();</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">protected</span> <span class="keyword">void</span> <span class="title">deliverResponse</span>(T response) {</div><div class="line"> listener.onResponse(response);</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">protected</span> Response<T> <span class="title">parseNetworkResponse</span>(NetworkResponse response) {</div><div class="line"> <span class="keyword">try</span> {</div><div class="line"> String json = <span class="keyword">new</span> String(</div><div class="line"> response.data,</div><div class="line"> HttpHeaderParser.parseCharset(response.headers));</div><div class="line"> <span class="keyword">return</span> Response.success(</div><div class="line"> gson.fromJson(json, clazz),</div><div class="line"> HttpHeaderParser.parseCacheHeaders(response));</div><div class="line"> } <span class="keyword">catch</span> (UnsupportedEncodingException e) {</div><div class="line"> <span class="keyword">return</span> Response.error(<span class="keyword">new</span> ParseError(e));</div><div class="line"> } <span class="keyword">catch</span> (JsonSyntaxException e) {</div><div class="line"> <span class="keyword">return</span> Response.error(<span class="keyword">new</span> ParseError(e));</div><div class="line"> }</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
<p>在这里没有将<t>具体化实现，而是可以传递一个Class进来，并使用网络获取的响应和Gson来进行Class的实例化。</t></p>
<blockquote>
<p>关于Volley使用的介绍就写到这里，可能会存在一些错误，欢迎指正交流。接下来几篇关于Volley的文章将讲一些Volley内部实现里比较有意思的地方。<br>最后奉上一个官方的介绍视频：<a href="https://developers.google.com/events/io/sessions/325304728" target="_blank" rel="external">点我！</a></p>
</blockquote>
]]></content>
<summary type="html">
<![CDATA[<blockquote>
<p><em>笔者小菜，文中可能会有一些误解或者错误的地方，欢迎指出交流</em></p>
</blockquote>
<h2 id="什么是Volley">什么是Volley</h2>
<p>Volley是google在2013年IO大会上推出的一个轻量级HTTP库，可以让Android上面的网络操作的构建变得异常简单，而且响应更加迅速。据说google内部测试了很多种HTTP库，Volley在每一项测试中都取得了最好的成绩。真假不知道，但是这个开源库的内部实现肯定会引起程序猿的兴趣，它内部是如何实现的呢？我们能从这个开源库里面学到一些什么东西呢？这就是接下来一系列的博文给大家讲述的内容。</p>
]]>
</summary>
<category term="android,volley" scheme="http://jinyudong.com/tags/android-volley/"/>
</entry>
<entry>
<title><![CDATA[Introducing RecyclerView(二)]]></title>
<link href="http://jinyudong.com/2014/11/14/add-listener-on-recyclerview/"/>
<id>http://jinyudong.com/2014/11/14/add-listener-on-recyclerview/</id>
<published>2014-11-14T12:29:10.000Z</published>
<updated>2014-11-14T13:04:27.000Z</updated>
<content type="html"><![CDATA[<p>当使用了一段时间的RecyclerView，发现为其每一项添加点击事件并没有ListView那么轻松，像ListView直接加个OnItemClickListener就行了。<strong>实际上我们不要把RecyclerView当做ListView的一个升级版</strong>，希望大家把他看做一个容器，同时里面包含了很多不同的Item，它们可以以不同方式排列组合，非常灵活，点击方式你可以按照你自己的意愿进行实现。</p>
<p>本节主要讲解如何为RecyclerView添加点击事件, 并简单介绍如何进行Item增加删除。</p>
<a id="more"></a>
<h2 id="添加点击事件">添加点击事件</h2>
<p><a href="http://jinyudong.com/2014/11/13/Introduce-RecyclerView-%E4%B8%80/" target="_blank" rel="external">上一节</a>中我们讲了如何使用RecyclerView的Adpater，其实我们会发现，Adapter是添加点击事件一个很好的地方，里面是构造布局等View的主要场所，也是数据和布局进行绑定的地方。首先我们在Adapter中创建一个实现点击接口，其中view是点击的Item，data是我们的数据，因为我们想知道我点击的区域部分的数据是什么，以便我下一步进行操作：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="keyword">static</span> <span class="class"><span class="keyword">interface</span> <span class="title">OnRecyclerViewItemClickListener</span> </span>{</div><div class="line"> <span class="keyword">void</span> onClick(View view , DataModel data);</div><div class="line">}</div></pre></td></tr></table></figure>
<p>定义完接口，添加接口和设置Adapter接口的方法：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">private</span> OnRecyclerViewItemClickListener mOnItemClickListener = <span class="keyword">null</span>;</div><div class="line"><span class="keyword">public</span> <span class="keyword">void</span> <span class="title">setOnItemClickListener</span>(OnRecyclerViewItemClickListener listener) {</div><div class="line"> <span class="keyword">this</span>.mOnItemClickListener = listener;</div><div class="line">}</div></pre></td></tr></table></figure>
<p>那么这个接口用在什么地方呢？如下代码所示，我们为Adapter实现OnClickListener方法：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">MyAdapter</span> <span class="keyword">extends</span> <span class="title">RecyclerView</span>.<span class="title">Adapter</span><<span class="title">MyAdapter</span>.<span class="title">ViewHolder</span>> <span class="keyword">implements</span> <span class="title">View</span>.<span class="title">OnClickListener</span></span>{</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> ViewHolder <span class="title">onCreateViewHolder</span>(ViewGroup viewGroup, <span class="keyword">final</span> <span class="keyword">int</span> i) {</div><div class="line"> View view = LayoutInflater.from(viewGroup.getContext())</div><div class="line"> .inflate(R.layout.item, viewGroup, <span class="keyword">false</span>);</div><div class="line"> ViewHolder vh = <span class="keyword">new</span> ViewHolder(view);</div><div class="line"> <span class="comment">//将创建的View注册点击事件</span></div><div class="line"> view.setOnClickListener(<span class="keyword">this</span>);</div><div class="line"> <span class="keyword">return</span> vh;</div><div class="line"> }</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onBindViewHolder</span>(ViewHolder viewHolder, <span class="keyword">final</span> <span class="keyword">int</span> i) {</div><div class="line"> viewHolder.mTextView.setText(datas.get(i).title);</div><div class="line"> <span class="comment">//将数据保存在itemView的Tag中，以便点击时进行获取</span></div><div class="line"> viewHolder.itemView.setTag(datas.get(i));</div><div class="line"> }</div><div class="line"> ...</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onClick</span>(View v) {</div><div class="line"> <span class="keyword">if</span> (mOnItemClickListener != <span class="keyword">null</span>) {</div><div class="line"> <span class="comment">//注意这里使用getTag方法获取数据</span></div><div class="line"> mOnItemClickListener.onClick(v,(DataModel)v.getTag());</div><div class="line"> }</div><div class="line"> }</div><div class="line"> ...</div><div class="line">}</div></pre></td></tr></table></figure>
<p>做完这些事情，我们就可以在Activity或其他地方为RecyclerView添加项目点击事件了，如在MainActivity中：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line">mAdapter = <span class="keyword">new</span> MyAdapter(getDummyDatas());</div><div class="line">mRecyclerView.setAdapter(mAdapter);</div><div class="line">mAdapter.setOnItemClickListener(<span class="keyword">new</span> MyAdapter.OnRecyclerViewItemClickListener() {</div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onClick</span>(View view, DataModel data) {</div><div class="line"> <span class="comment">//DO your fucking bussiness here!</span></div><div class="line"> }</div><div class="line">});</div></pre></td></tr></table></figure>
<p>完成了以上代码就可以为RecyclerView添加项目点击事件了，下面我们来看看RecyclerView如何添加和删除数据并在界面上显示。</p>
<h2 id="添加删除数据">添加删除数据</h2>
<p>以前在ListView当中，我们只要修改后数据用Adapter的notifyDatasetChange一下就可以更新界面。然而在RecyclerView中还有一些更高级的用法：</p>
<p>添加数据：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="keyword">void</span> <span class="title">addItem</span>(DataModel content, <span class="keyword">int</span> position) {</div><div class="line"> datas.add(position, content);</div><div class="line"> notifyItemInserted(position); <span class="comment">//Attention!</span></div><div class="line">}</div></pre></td></tr></table></figure>
<p>删除数据：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="keyword">void</span> <span class="title">removeItem</span>(DataModel model) {</div><div class="line"> <span class="keyword">int</span> position = datas.indexOf(model);</div><div class="line"> datas.remove(position);</div><div class="line"> notifyItemRemoved(position);<span class="comment">//Attention!</span></div><div class="line">}</div></pre></td></tr></table></figure>
<p>值得注意的是RecyclerView的添加删除都是有默认的动画效果的，如果没有效果可以添加如下代码：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">mRecyclerView.setItemAnimator(<span class="keyword">new</span> DefaultItemAnimator());</div></pre></td></tr></table></figure>
<p>当然啦你也可以自己定义你自己的Animator，等我研究明白了也来讲一讲如何自定义这些效果~</p>
<p>感谢阅读，如果有什么建议或是错误的地方可以在底下留言~</p>
]]></content>
<summary type="html">
<![CDATA[<p>当使用了一段时间的RecyclerView，发现为其每一项添加点击事件并没有ListView那么轻松，像ListView直接加个OnItemClickListener就行了。<strong>实际上我们不要把RecyclerView当做ListView的一个升级版</strong>，希望大家把他看做一个容器，同时里面包含了很多不同的Item，它们可以以不同方式排列组合，非常灵活，点击方式你可以按照你自己的意愿进行实现。</p>
<p>本节主要讲解如何为RecyclerView添加点击事件, 并简单介绍如何进行Item增加删除。</p>
]]>
</summary>
<category term="android" scheme="http://jinyudong.com/tags/android/"/>
<category term="recycler view" scheme="http://jinyudong.com/tags/recycler-view/"/>
<category term="sdk" scheme="http://jinyudong.com/tags/sdk/"/>
</entry>
<entry>
<title><![CDATA[Introducing RecyclerView(一)]]></title>
<link href="http://jinyudong.com/2014/11/13/Introduce-RecyclerView-%E4%B8%80/"/>
<id>http://jinyudong.com/2014/11/13/Introduce-RecyclerView-一/</id>
<published>2014-11-12T16:06:42.000Z</published>
<updated>2014-11-13T16:12:43.000Z</updated>
<content type="html"><![CDATA[<p>RecyclerView 是Android L版本中新添加的一个用来取代ListView的SDK，它的灵活性与可替代性比listview更好。接下来通过一系列的文章讲解如何使用RecyclerView,彻底抛弃ListView.</p>
<h2 id="介绍">介绍</h2>
<p>RecyclerView与ListView原理是类似的：都是仅仅维护少量的View并且可以展示大量的数据集。RecyclerView用以下两种方式简化了数据的展示和处理:</p>
<ul>
<li>使用LayoutManager来确定每一个item的排列方式。</li>
<li>为增加和删除项目提供默认的动画效果。 </li>
</ul>
<a id="more"></a>
<p>你也可以定义你自己的LayoutManager和添加删除动画，RecyclerView项目结构如下：</p>
<p><img src="https://developer.android.com/training/material/images/RecyclerView.png" alt=""></p>
<ul>
<li><p>Adapter：使用RecyclerView之前，你需要一个继承自RecyclerView.Adapter的适配器，作用是将数据与每一个item的界面进行绑定。</p>
</li>
<li><p>LayoutManager：用来确定每一个item如何进行排列摆放，何时展示和隐藏。回收或重用一个View的时候，LayoutManager会向适配器请求新的数据来替换旧的数据，这种机制避免了创建过多的View和频繁的调用findViewById方法（与ListView原理类似）。</p>
</li>
</ul>
<p>目前SDK中提供了三种自带的LayoutManager:</p>
<ul>
<li><a href="https://developer.android.com/reference/android/support/v7/widget/LinearLayoutManager.html" target="_blank" rel="external">LinearLayoutManager</a></li>
<li><a href="https://developer.android.com/reference/android/support/v7/widget/GridLayoutManager.html" target="_blank" rel="external">GridLayoutManager</a></li>
<li><a href="https://developer.android.com/reference/android/support/v7/widget/StaggeredGridLayoutManager.html" target="_blank" rel="external">StaggeredGridLayoutManager</a></li>
</ul>
<h2 id="示例">示例</h2>
<p>本节所示示例是一个最简单的使用方法，在接下来几节中将会介绍更多RecyclerView的别的一些屌爆的用法。作者用的环境是Android Studio 0.8.6。</p>
<h3 id="1、添加依赖">1、添加依赖</h3>
<p>在AS的<code>build.gradle</code>中添加依赖，然后同步一下就可以引入依赖包：</p>
<figure class="highlight"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div></pre></td><td class="code"><pre><div class="line">dependencies {</div><div class="line"> <span class="keyword">...</span></div><div class="line"> compile <span class="string">'com.android.support:recyclerview-v7:21.0.+'</span></div><div class="line">}</div></pre></td></tr></table></figure>
<h3 id="2、编写代码">2、编写代码</h3>
<p>添加完依赖之后，就开始写代码了，与ListView用法类似，也是先在xml布局文件中创建一个RecyclerView的布局：</p>
<figure class="highlight xml"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div></pre></td><td class="code"><pre><div class="line"><span class="tag"><<span class="title">RelativeLayout</span> <span class="attribute">xmlns:android</span>=<span class="value">"http://schemas.android.com/apk/res/android"</span></span></div><div class="line"> <span class="attribute">xmlns:tools</span>=<span class="value">"http://schemas.android.com/tools"</span></div><div class="line"> <span class="attribute">android:layout_width</span>=<span class="value">"match_parent"</span></div><div class="line"> <span class="attribute">android:layout_height</span>=<span class="value">"match_parent"</span></div><div class="line"> <span class="attribute">tools:context</span>=<span class="value">".MainActivity"</span>></div><div class="line"> <span class="tag"><<span class="title">android.support.v7.widget.RecyclerView</span></span></div><div class="line"> <span class="attribute">android:id</span>=<span class="value">"@+id/my_recycler_view"</span></div><div class="line"> <span class="attribute">android:layout_width</span>=<span class="value">"match_parent"</span></div><div class="line"> <span class="attribute">android:layout_height</span>=<span class="value">"match_parent"</span></div><div class="line"> <span class="attribute">android:scrollbars</span>=<span class="value">"vertical"</span> /></div><div class="line"><span class="tag"></<span class="title">RelativeLayout</span>></span></div></pre></td></tr></table></figure>
<p>创建完布局之后在MainActivity中获取这个RecyclerView，并声明<code>LayoutManager</code>与<code>Adapter</code>，代码如下：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div></pre></td><td class="code"><pre><div class="line">mRecyclerView = (RecyclerView)findViewById(R.id.my_recycler_view);</div><div class="line"><span class="comment">//创建默认的线性LayoutManager</span></div><div class="line">mLayoutManager = <span class="keyword">new</span> LinearLayoutManager(<span class="keyword">this</span>);</div><div class="line">mRecyclerView.setLayoutManager(mLayoutManager);</div><div class="line"><span class="comment">//如果可以确定每个item的高度是固定的，设置这个选项可以提高性能</span></div><div class="line">mRecyclerView.setHasFixedSize(<span class="keyword">true</span>);</div><div class="line"><span class="comment">//创建并设置Adapter</span></div><div class="line">mAdapter = <span class="keyword">new</span> MyAdapter(getDummyDatas());</div><div class="line">mRecyclerView.setAdapter(mAdapter);</div></pre></td></tr></table></figure>
<p>接下来的问题就是Adapter的创建：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div><div class="line">18</div><div class="line">19</div><div class="line">20</div><div class="line">21</div><div class="line">22</div><div class="line">23</div><div class="line">24</div><div class="line">25</div><div class="line">26</div><div class="line">27</div><div class="line">28</div><div class="line">29</div><div class="line">30</div><div class="line">31</div><div class="line">32</div></pre></td><td class="code"><pre><div class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">MyAdapter</span> <span class="keyword">extends</span> <span class="title">RecyclerView</span>.<span class="title">Adapter</span><<span class="title">MyAdapter</span>.<span class="title">ViewHolder</span>> </span>{</div><div class="line"> <span class="keyword">public</span> String[] datas = <span class="keyword">null</span>;</div><div class="line"> <span class="keyword">public</span> <span class="title">MyAdapter</span>(String[] datas) {</div><div class="line"> <span class="keyword">this</span>.datas = datas;</div><div class="line"> }</div><div class="line"> <span class="comment">//创建新View，被LayoutManager所调用</span></div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> ViewHolder <span class="title">onCreateViewHolder</span>(ViewGroup viewGroup, <span class="keyword">int</span> i) {</div><div class="line"> View view = LayoutInflater.from(viewGroup.getContext())</div><div class="line"> .inflate(R.layout.item,viewGroup,<span class="keyword">false</span>);</div><div class="line"> ViewHolder vh = <span class="keyword">new</span> ViewHolder(view);</div><div class="line"> <span class="keyword">return</span> vh;</div><div class="line"> }</div><div class="line"> <span class="comment">//将数据与界面进行绑定的操作</span></div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">void</span> <span class="title">onBindViewHolder</span>(ViewHolder viewHolder, <span class="keyword">int</span> i) {</div><div class="line"> viewHolder.mTextView.setText(datas[i]);</div><div class="line"> }</div><div class="line"> <span class="comment">//获取数据的数量</span></div><div class="line"> <span class="annotation">@Override</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">int</span> <span class="title">getItemCount</span>() {</div><div class="line"> <span class="keyword">return</span> datas.length;</div><div class="line"> }</div><div class="line"> <span class="comment">//自定义的ViewHolder，持有每个Item的的所有界面元素</span></div><div class="line"> <span class="keyword">public</span> <span class="keyword">static</span> <span class="class"><span class="keyword">class</span> <span class="title">ViewHolder</span> <span class="keyword">extends</span> <span class="title">RecyclerView</span>.<span class="title">ViewHolder</span> </span>{</div><div class="line"> <span class="keyword">public</span> TextView mTextView;</div><div class="line"> <span class="keyword">public</span> <span class="title">ViewHolder</span>(View view){</div><div class="line"> <span class="keyword">super</span>(view);</div><div class="line"> mTextView = (TextView) view.findViewById(R.id.text);</div><div class="line"> }</div><div class="line"> }</div><div class="line">}</div></pre></td></tr></table></figure>
<h3 id="3、运行">3、运行</h3>
<p>写完这些代码这个例子既可以跑起来了。从例子也可以看出来，RecyclerView的用法并不比ListView复杂，反而更灵活好用，它将数据、排列方式、数据的展示方式都分割开来，因此可定制型，自定义的形式也非常多，非常灵活。</p>
<h4 id="横向布局">横向布局</h4>
<p>如果想要一个横向的List只要设置LinearLayoutManager如下就行，注意要声明mLayoutManager的类型是LinearLayoutManager而不是父类LayoutManager：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">mLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);</div></pre></td></tr></table></figure>
<h4 id="Grid布局">Grid布局</h4>
<p>如果想要一个Grid布局的列表，只要声明LayoutManager为GridLayoutManager即可：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">mLayoutManager = <span class="keyword">new</span> GridLayoutManager(context,columNum);</div><div class="line">mRecyclerView.setLayoutManager(mLayoutManager);</div></pre></td></tr></table></figure>
<p>注意，在Grid布局中也可以设置列表的Orientation属性，来实现横向和纵向的Grid布局。</p>
<h4 id="瀑布流布局">瀑布流布局</h4>
<p>瀑布流就使用StaggeredGridLayoutManager吧，具体方法与上面类似，就不做介绍啦。</p>
<h2 id="总结">总结</h2>
<p>本节介绍的是一个最最简单的RecyclerView的使用方法，后面将介绍一些更高级的用法。</p>
]]></content>
<summary type="html">
<![CDATA[<p>RecyclerView 是Android L版本中新添加的一个用来取代ListView的SDK，它的灵活性与可替代性比listview更好。接下来通过一系列的文章讲解如何使用RecyclerView,彻底抛弃ListView.</p>
<h2 id="介绍">介绍</h2>
<p>RecyclerView与ListView原理是类似的：都是仅仅维护少量的View并且可以展示大量的数据集。RecyclerView用以下两种方式简化了数据的展示和处理:</p>
<ul>
<li>使用LayoutManager来确定每一个item的排列方式。</li>
<li>为增加和删除项目提供默认的动画效果。 </li>
</ul>
]]>
</summary>
<category term="android" scheme="http://jinyudong.com/tags/android/"/>
<category term="recycler view" scheme="http://jinyudong.com/tags/recycler-view/"/>
<category term="sdk" scheme="http://jinyudong.com/tags/sdk/"/>
</entry>
<entry>
<title><![CDATA[Android Studio SDK 更新方法]]></title>
<link href="http://jinyudong.com/2014/11/12/Android-Studio-SDK-Update/"/>
<id>http://jinyudong.com/2014/11/12/Android-Studio-SDK-Update/</id>
<published>2014-11-12T14:25:38.000Z</published>
<updated>2014-11-13T05:30:16.000Z</updated>
<content type="html"><![CDATA[<p>通常情况下，下载Android SDK需要连接谷歌的服务器进行下载，由于国内水深火热的网络，速度基本为0.好在国内也有一个更新的镜像地址。本文章介绍如何在不翻墙的情况下，使用国内镜像地址，更新android sdk.</p>
<a id="more"></a>
<h2 id="设置host">设置host</h2>
<p>首先在etc/hosts中设置hosts，需要管理员权限。使用vim对hosts进行编辑：</p>
<figure class="highlight bash"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line"><span class="built_in">sudo</span> vim hosts</div></pre></td></tr></table></figure>
<p>输入密码后进行编辑，添加如下几行：</p>
<figure class="highlight bash"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line"><span class="comment">#Google主页 </span></div><div class="line"><span class="number">203.208</span>.<span class="number">46.146</span> www.google.com </div><div class="line"><span class="comment">##这行是为了方便打开Android开发官网 现在好像不翻也可以打开 </span></div><div class="line"><span class="number">74.125</span>.<span class="number">113.121</span> developer.android.com </div><div class="line"><span class="comment">##更新的内容从以下地址下载 </span></div><div class="line"><span class="number">203.208</span>.<span class="number">46.146</span> dl.google.com </div><div class="line"><span class="number">203.208</span>.<span class="number">46.146</span> dl-ssl.google.com</div></pre></td></tr></table></figure>
<h2 id="更改Android_SDK_Manager设置">更改Android SDK Manager设置</h2>
<p><img src="http://dl2.iteye.com/upload/attachment/0097/7095/7e128ac5-bd43-38f4-8f8d-eaf388138c90.png" alt=""></p>
<p>在Preference中进行设置，修改配置如下：</p>
<blockquote>
<p>HTTP Proxy Server: mirrors.neusoft.edu.cn</p>
<p>HTTP Proxy Port: 80</p>
</blockquote>
<p>然后勾选强制使用http:</p>
<p><img src="http://dl2.iteye.com/upload/attachment/0097/7097/c75ffa94-21b5-3d90-8a22-a55d1c78b5d6.png" alt=""></p>
<p>然后就大功告成，可以愉快飞速的下载Android SDK而不用担心翻墙网速等问题啦。</p>
<p>参考：<a href="http://qianjigui.iteye.com/blog/2074695" target="_blank" rel="external">Android Studio SDK Manager无法正常下载如何设置</a></p>
]]></content>
<summary type="html">
<![CDATA[<p>通常情况下，下载Android SDK需要连接谷歌的服务器进行下载，由于国内水深火热的网络，速度基本为0.好在国内也有一个更新的镜像地址。本文章介绍如何在不翻墙的情况下，使用国内镜像地址，更新android sdk.</p>
]]>
</summary>
<category term="android" scheme="http://jinyudong.com/tags/android/"/>
<category term="android studio" scheme="http://jinyudong.com/tags/android-studio/"/>
<category term="sdk" scheme="http://jinyudong.com/tags/sdk/"/>
</entry>
<entry>
<title><![CDATA[How to create a ripple effect]]></title>
<link href="http://jinyudong.com/2014/11/11/How-to-create-ripple-effect/"/>
<id>http://jinyudong.com/2014/11/11/How-to-create-ripple-effect/</id>
<published>2014-11-11T15:07:25.000Z</published>
<updated>2014-11-11T15:15:46.000Z</updated>
<content type="html"><![CDATA[<p>挖个坑，分析一下Material design 中的ripple effect是如何实现的。</p>
]]></content>
<summary type="html">
<![CDATA[<p>挖个坑，分析一下Material design 中的ripple effect是如何实现的。</p>
]]>
</summary>
<category term="android" scheme="http://jinyudong.com/tags/android/"/>
<category term="material design" scheme="http://jinyudong.com/tags/material-design/"/>
</entry>
</feed>