update watcher let the auto update theme can be canceled

[chzuka]

Pull request type

Please check the type of change your PR introduces:

• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes

What is the current behavior?

• There is no method to cancel a watch in the watcher class.
• It is not possible to modify the background style independently without modifying the overall theme.
• The background color of the listviewitem is too light.

Issue Number: N/A

What is the new behavior?

• Added the unwatch method for canceling the watch.
• Deleted the judgment of whether the themetype is equal.
• Changed the background color of the listviewitem.

Other information

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