Android™ Application Development - Bahar Ali Khan

Chapter 11: Advanced Android Development
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android:fromYScale=”1.0”
android:toYScale=”0.0”
android:pivotX=”50%”
android:pivotY=”50%”
android:startOffset=”500”
android:duration=”500” />
As you can see, it’s generally both easier and more intuitive to create your animation sequences using
an external animation resource.
Applying Tweened Animations
Animations can be applied to any View by calling its startAnimation method and passing in the Animation
or Animation Set to apply.
Animation sequences will run once and then stop, unless you modify this behavior using the
setRepeatMode and setRepeatCount methods on the Animation or Animation Set. You can force an
animation to loop or ping-pong by setting the repeat mode of RESTART or REVERSE. Setting the repeat
count controls the number of times the animation will repeat.
The following code snippet shows an Animation that repeats indefi nitely:
myAnimation.setRepeatMode(Animation.RESTART);
myAnimation.setRepeatCount(Animation.INFINITE);
myView.startAnimation(myAnimation);
Using Animation Listeners
The AnimationListener lets you create an event handler that’s fi red when an animation begins or
ends. This lets you perform actions before or after an animation has completed, such as changing the
View contents or chaining multiple animations.
Call setAnimationListener on an Animation object, and pass in a new implementation of
AnimationListener, overriding onAnimationEnd, onAnimationStart, and onAnimationRepeat as
required.
The following skeleton code shows the basic implementation of an Animation Listener:
myAnimation.setAnimationListener(new AnimationListener() {
public void onAnimationEnd(Animation _animation) {
// TODO Do something after animation is complete.
}
public void onAnimationRepeat(Animation _animation) {