Question

I am having trouble getting my button animation to run when my activity starts up, I am sorta new here and any suggestion will be grateful. Here is what I have at the beginning of my Activity…..

    // this is flag for home key press
public static boolean isHome = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
    WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.press);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);



    // init data
    init();

    // start player display
    start(10000 * 60 * 60 * 24);

    spin++;

    // play background music
    playmp3(R.raw.press);
 }
//HERE IS THE WORKING VERSION THAT WAS CORRECTED BY THE ANSWER BELOW
 public void onWindowFocusChanged(boolean hasFocus) {
     super.onWindowFocusChanged(hasFocus);

     if(hasFocus) {
     final Button b_1 = (Button) findViewById(R.id.bttest);
         b_1.setBackgroundResource(R.drawable.animation);
         AnimationDrawable b1Amin = (AnimationDrawable) b_1.getBackground();
     b1Amin.start();
    }
 }

and here is my animation.xml in my drawable file

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
  android:oneshot="false">
<item android:drawable="@drawable/btn1" android:duration="100" />
<item android:drawable="@drawable/btn2" android:duration="100" />
<item android:drawable="@drawable/btn3" android:duration="100" />
<item android:drawable="@drawable/btn4" android:duration="100" />
<item android:drawable="@drawable/btn5" android:duration="100" />
<item android:drawable="@drawable/btn6" android:duration="100" />
<item android:drawable="@drawable/btn7" android:duration="100" />
<item android:drawable="@drawable/btn8" android:duration="100" />

</animation-list>

Answer 1

The API documentation for AnimationDrawable#start() explicitly states that it should not be invoked from onCreate(Bundle) since the AnimationDrawable has not been attached to the window yet. Follow the advice in the docs and invoke start() from onWindowFocusChanged(boolean) instead.