Add Picture-in-Picture support to keep the camera alive in the background

Author: n8fr8

src/main/AndroidManifest.xml

@@ -64,10 +64,14 @@
             android:screenOrientation="portrait" />
         <activity
             android:name=".MonitorActivity"
-            android:configChanges="orientation|screenSize"
             android:label="@string/app_name"
             android:screenOrientation="portrait"
-            android:launchMode="singleTop" />
+            android:launchMode="singleTop"
+            android:resizeableActivity="true"
+            android:supportsPictureInPicture="true"
+            android:configChanges=
+                "screenSize|smallestScreenSize|screenLayout|orientation"
+            />
         <activity
             android:name=".ui.VideoPlayerActivity"
             android:configChanges="orientation|keyboardHidden|screenLayout|screenSize"

src/main/java/org/havenapp/main/MonitorActivity.java

@@ -19,6 +19,8 @@
 import android.Manifest;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.content.res.Configuration;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.CountDownTimer;
 import android.os.Environment;
@@ -209,6 +211,18 @@ private void doCancel() {
 
     }
 
+    @Override
+    public void onPictureInPictureModeChanged (boolean isInPictureInPictureMode, Configuration newConfig) {
+        if (isInPictureInPictureMode) {
+            // Hide the full-screen UI (controls, etc.) while in picture-in-picture mode.
+            findViewById(R.id.buttonBar).setVisibility(View.GONE);
+        } else {
+            // Restore the full-screen UI.
+            findViewById(R.id.buttonBar).setVisibility(View.VISIBLE);
+
+        }
+    }
+
     private void showSettings() {
 
         Intent i = new Intent(this, SettingsActivity.class);
@@ -288,21 +302,36 @@ private void initMonitor() {
 
     }
 
-    /**
-     * Closes the monitor activity and unset session properties
-     */
-    private void close() {
-
-        finish();
 
+    @Override
+    public void onUserLeaveHint () {
+        if (mIsMonitoring) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+                enterPictureInPictureMode();
+            }
+        }
     }
-
     /**
      * When user closes the activity
      */
     @Override
     public void onBackPressed() {
-        close();
+
+        if (mIsMonitoring) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+                enterPictureInPictureMode();
+            }
+            else
+            {
+                finish();
+            }
+        }
+        else
+        {
+            finish();
+        }
+
+
     }
 
     private void showTimeDelayDialog() {

src/main/res/layout/activity_monitor.xml

@@ -72,6 +72,7 @@
             android:layout_height="match_parent"
             android:gravity="center_horizontal|bottom"
             android:orientation="horizontal"
+            android:id="@+id/buttonBar"
             android:padding="10dp">
 
             <ImageView