Animations定义：Animations提供了一系列的动画效果，这些效果可以应用在绝大多数的控件。
Animations从总体来看分为两大类：
1、Tweened Animations 该类提供了旋转、移动、伸展和淡出的效果
2、Frame-by-FrameAnimations 该类可以创建一个Drawable序列，这些Drawable可以按照指定的时间间歇一个个的显示
Tweened Animations的分类：
1、Alpha：淡入淡出效果
2、Scale：缩放效果
3、Rotate：旋转效果
4、Translate：移动效果
使用Tweened Animations的步骤：
1、创建一个AnimationSet对象
2、根据需要创建相应 的Animation对象
3、根据动画的需要，为Animation对象设置相应的数据
4、将Animation对象添加到AnimationSet对象当中
5、使用控件对象开始执行AnimationSet
例如：为控件绑定Alpha动画的过程
//创建一个AnimationSet对象 AnimationSet animationSet = new AnimationSet(true); //创建一个AlphaAnimation对象 AlphaAnimation alphaAnimation = new AlphaAnimation(1, 0); //设置动画执行的时间（单位：毫秒） alphaAnimation.setDuration(1000); //将AlphaAnimation对象添加到AnimationSet当中 animationSet.addAnimation(alphaAnimation); //使用ImageView的startAnimation方法开始执行动画 imageView.startAnimation(animationSet);
public class MainActivity extends Activity {
private ImageView imageView = null;
private Button rotateButton = null;
private Button scaleButton = null;
private Button alphaButton = null;
private Button translateButton = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
imageView = (ImageView) findViewById(R.id.imageViewId);
rotateButton = (Button) findViewById(R.id.rotateButtonId);
rotateButton.setOnClickListener(new RotateButtonListener());
scaleButton = (Button) findViewById(R.id.scaleButtonId);
scaleButton.setOnClickListener(new ScaleButtonListener());
alphaButton = (Button) findViewById(R.id.alphaButtonId);
alphaButton.setOnClickListener(new AlphaButtonListener());
translateButton = (Button) findViewById(R.id.translateButtonId);
translateButton.setOnClickListener(new TranslateButtonListener());
}
private class RotateButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
AnimationSet animationSet = new AnimationSet(true);
RotateAnimation rotateAnimation = new RotateAnimation(0, 360,
Animation.RELATIVE_TO_PARENT, 1f,
Animation.RELATIVE_TO_PARENT, 0f);
rotateAnimation.setDuration(5000);
animationSet.addAnimation(rotateAnimation);
imageView.startAnimation(animationSet);
}
}
private class ScaleButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
AnimationSet animationSet = new AnimationSet(true);
ScaleAnimation scaleAnimation = new ScaleAnimation(1, 0.1f, 1, 0.1f,
Animation.RELATIVE_TO_SELF, 0.5f,
Animation.RELATIVE_TO_SELF, 0.5f);
animationSet.addAnimation(scaleAnimation);
animationSet.setStartOffset(1000);
animationSet.setFillAfter(true);
animationSet.setFillBefore(false);
animationSet.setDuration(2000);
imageView.startAnimation(animationSet);
}
}
private class AlphaButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
AnimationSet animationSet = new AnimationSet(true);
AlphaAnimation alphaAnimation = new AlphaAnimation(1, 0);
alphaAnimation.setDuration(1000);
animationSet.addAnimation(alphaAnimation);
imageView.startAnimation(animationSet);
}
}
private class TranslateButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
AnimationSet animationSet = new AnimationSet(true);
TranslateAnimation translateAnimation = new TranslateAnimation(
Animation.RELATIVE_TO_SELF, 0f,
Animation.RELATIVE_TO_SELF, 0.5f,
Animation.RELATIVE_TO_SELF, 0f,
Animation.RELATIVE_TO_SELF, 1.0f);
translateAnimation.setDuration(1000);
animationSet.addAnimation(translateAnimation);
imageView.startAnimation(animationSet);
}
}
}
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对于上面使用动画的方法，在Java代码中使用，不利于代码的重复使用，更不利于代码的维护，所以就出现了下面的方法，在xml代码中定义动画。其步骤为：
1、在res文件夹下定义一个anim的文件夹
2、创建xml文件，并加入set标签，该标签如下：
<set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator"> </set>
4、在代码当中使用AnimationUtils装载xml文件，并生成Animation对象
具体实现如下：
alpha.xml代码：
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator"> <alpha android:fromAlpha="1.0" android:toAlpha="0.0" android:startOffset="500" android:duration="500" /> </set>
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator"> <rotate android:fromDegrees="0" android:toDegrees="360" android:pivotX="50%" android:pivotY="50%" android:duration="5000" /> </set>
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator"> <scale android:fromXScale="1.0" android:toXScale="0.0" android:fromYScale="1.0" android:toYScale="0.0" android:pivotX="50%" android:pivotY="50%" android:duration="2000" /> </set>
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator"> <translate android:fromXDelta="50%" android:toXDelta="100%" android:fromYDelta="0%" android:toYDelta="100%" android:duration="2000" /> </set>
public class MainActivity extends Activity {
private ImageView imageView = null;
private Button rotateButton = null;
private Button scaleButton = null;
private Button alphaButton = null;
private Button translateButton = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
imageView = (ImageView) findViewById(R.id.imageViewId);
rotateButton = (Button) findViewById(R.id.rotateButtonId);
rotateButton.setOnClickListener(new RotateButtonListener());
scaleButton = (Button) findViewById(R.id.scaleButtonId);
scaleButton.setOnClickListener(new ScaleButtonListener());
alphaButton = (Button) findViewById(R.id.alphaButtonId);
alphaButton.setOnClickListener(new AlphaButtonListener());
translateButton = (Button) findViewById(R.id.translateButtonId);
translateButton.setOnClickListener(new TranslateButtonListener());
}
private class RotateButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.rotate);
imageView.startAnimation(animation);
}
}
private class ScaleButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.sacle);
imageView.startAnimation(animation);
}
}
private class AlphaButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.alpha);
imageView.startAnimation(animation);
}
}
private class TranslateButtonListener implements OnClickListener {
@Override
public void onClick(View view) {
Animation animation = (Animation) AnimationUtils.loadAnimation(MainActivity.this, R.anim.translate);
imageView.startAnimation(animation);
}
}
}原文：http://blog.csdn.net/ling1510/article/details/23337917