Status button with background as AnimationDrawable in Android

Question

I have created custom buttons in Android for a while. Everything was simple, just made image resources for button states and made a selector for it. Everything went smoothly and pleasantly. Now I am faced with a new situation. I created an animation and set it as the background for my button.

<animation-list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false"> <item android:drawable="@drawable/frame1" android:duration="600" /> <item android:drawable="@drawable/frame2" android:duration="300" /> <item android:drawable="@drawable/frame3" android:duration="500" /> </animation-list> 

If I set up the animation as the Background button, it works fine. If I try to make a simple selector

 <?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_pressed="false" android:drawable="@drawable/animation" /> <item android:state_pressed="true" android:drawable="@drawable/pressed" /> </selector> 

where the normal state of the button will have animation as a background, and pressing it will be a static image, everything does not work correctly.

In my main activity, on onWindowFocus, I get the button background and start the animation

  @Override public void onWindowFocusChanged(boolean hasFocus) { super.onWindowFocusChanged(hasFocus); btn = (Button)findViewById(R.id.btnAnim); btnAnimation = (AnimationDrawable) btnAnim.getBackground(); btnAnimation.start(); } 

There seems to be a problem here, because my animation will not be correctly selected from the selector, and I get the following error:

 03-14 15:21:16.146: ERROR/AndroidRuntime(440): FATAL EXCEPTION: main 03-14 15:21:16.146: ERROR/AndroidRuntime(440): java.lang.ClassCastException: android.graphics.drawable.StateListDrawable 03-14 15:21:16.146: ERROR/AndroidRuntime(440): at com.bebenjoy.MainActivity.onWindowFocusChanged(MainActivity.java:53) 03-14 15:21:16.146: ERROR/AndroidRuntime(440): at ... 

Any idea on how to fix this? Thanks.

Answer 1

You are doing the wrong listing - your background resource is StateListDrawable , not AnimationDrawable . I would rather do something like:

 @Override public void onWindowFocusChanged(boolean hasFocus) { super.onWindowFocusChanged(hasFocus); btn = (Button)findViewById(R.id.btnAnim); StateListDrawable background = (StateListDrawable) btn.getBackground(); Drawable current = background.getCurrent(); if (current instanceof AnimationDrawable) { btnAnimation = (AnimationDrawable) current; btnAnimation.start(); } } 

Answer 2

My answer is a bit late, I know, but I ran into the same problem. I checked many solutions, but found only one. I tried to start the animation in onWindowFocusChanged (), to start the animation in aseparate thread, but this does not help.

I solved this problem using setVisible (boolean visible, boolean restart)

So you can try the following:

  private Button ImgBtn; private AnimationDrawable btnAnimation; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); btn = (Button)findViewById(R.id.button1); StateListDrawable background = (StateListDrawable) btn.getBackground(); btnAnimation = (AnimationDrawable) background.getCurrent(); btnAnimation.setVisible(true, true); // it works even in onCreate() } 

Hope this helps someone :)