I、逐帧动画
逐帧动画用以指定一系列用作View的背景的Drawable对象，感觉类似于幻灯片。
public class AnimationDrawable extends DrawableContainer implements Runnable, Animatable
public class DrawableContainer extends Drawable implements Drawable.Callback
一、应用实例：
1、在res/drawabe文件下建立<animation-list>
<?xml version="1.0"encoding="utf-8"?><animation-list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false"> <item android:drawable="@drawable/icon0" android:duration="500"/> <item android:drawable="@drawable/icon1" android:duration="500"/> <item android:drawable="@drawable/icon2" android:duration="500"/> <item android:drawable="@drawable/icon3" android:duration="500"/></animation-list>
android:oneshot为false时表示循环播放，默认为false
2、代码中使用逐帧动画
myImageView=(ImageView)findViewById(R.id.myImageView);myImageView.setBackgroundResource(R.drawable.myanimation); AnimationDrawable animationDrawable =(AnimationDrawable) myImageView.getBackground();animationDrawable.start();//animationDrawable.stop();
二、扩展知识：AnimationDrawable类
1、提供函数：
public void start()public void stop()public boolean isRunning()public int getNumberOfFrames()public Drawable getFrame(int index)public int getDuration(int i)public boolean isOneShot()public void setOneShot(boolean oneShot)/**Add a frame to the animation */public void addFrame(Drawable frame, int duration)
2、已定义了一个帧动画，如何做到播放其中的某几个连续帧；（比如本文中有4个帧，播放2-3帧）
分析：AnimationDrawable类提供了getFrame和getDuration方法，但是未提供相应的setter函数来控制播放的帧位置。AnimationDrawable类中有一个私有变量mCurFrame表示当前的播放帧。定义如下：
/** The current frame, may be -1 when not animating. */ private int mCurFrame = -1;
因为其为private变量，且未提供相应setter函数，故采用反射技术进行读写。
public class MyImageView extends ImageView{ private AnimationDrawable animationDrawable; public MyImageView(Context context, AttributeSet attrs) { super(context, attrs); setBackgroundResource(R.drawable.myanimation); animationDrawable = (AnimationDrawable) getBackground(); setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { animationDrawable.start(); } }); } @Override public void onDraw(Canvas canvas) { try { Field field = AnimationDrawable.class.getDeclaredField("mCurFrame"); field.setAccessible(true); int curFrame = field.getInt(animationDrawable); if(curFrame == 2) field.setInt(animationDrawable, 0); } catch(Exception e) { Log.e("AnimationDrawable", e.toString()); } super.onDraw(canvas); } }II、补间动画：
不同于逐帧动画，即设定好动画起始终止状态，中间由系统来补充
一、四种基本动画
1、缩放scale---ScaleAnimation
方法一：在res/anim文件下创建xml文件：
<!-- 缩放 --> <scale android:fromXScale="0.0" android:toXScale="1.0" android:fromYScale="0.0" android:toYScale="1.0" android:pivotX="50%" android:pivotY="50%" android:duration="1000" android:repeatCount="-1" android:repeatMode="reverse" /> <!-- fromXScale：沿X,Y轴的缩放比例 from-to--> <!-- pivotX：缩放的中心点位置，（占View大小的百分比） --> <!-- duration：持续时间 --> <!-- repeatCount:重复次数，默认为0，代表旋转一次；则设为n，旋转n+1次；设为-1或infinite，则为无限循环 --> <!-- repeatMode：重复模式，默认为restart-->
代码中使用：
Animation animation =AnimationUtils.loadAnimation(MainActivity.this,R.anim.anim_set); myImageView.startAnimation(animation);
方法二：
ScaleAnimation animation = new ScaleAnimation(0, 1, 0, 1); animation.setDuration(1000); animation.setRepeatCount(-1); animation.setRepeatMode(Animation.RESTART); myImageView.startAnimation(animation);
下面用法大同小异：
2、透明度alpha --- AlphaAnimation
<!-- 透明度 --> <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="1000" android:repeatCount="-1" android:repeatMode="reverse" />
3、旋转rotate --- RotateAnimation
<!-- 旋转 --> <rotate android:fromDegrees="0" android:toDegrees="360" android:pivotX="50%" android:pivotY="50%" android:duration="1000" android:repeatCount="2" android:repeatMode="restart" />
4、移动translate --- TranslateAnimation
<!-- 移动 --> <translate android:fromXDelta="0" android:toXDelta="1000" android:fromYDelta="0" android:toYDelta="1000" android:duration="1000" />
二、几种Anim的组合set
<?xmlversion="1.0"encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator" android:repeatMode="reverse" android:repeatCount="2" > <!-- 移动 --> <translate android:fromXDelta="0" android:toXDelta="1000" android:fromYDelta="0" android:toYDelta="1000" android:duration="1000" /> <!-- 缩放 --> <scale android:fromXScale="0.0" android:toXScale="1.0" android:fromYScale="0.0" android:toYScale="1.0" android:pivotX="50%" android:pivotY="50%" android:duration="1000" /> <!-- 透明度 --> <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="1000" /> <rotate android:fromDegrees="0" android:toDegrees="360" android:pivotX="50%" android:pivotY="50%" android:duration="1000" /></set>
android:interpolator是指每个动画开始和结束值间转换中所使用的差值器（动画渲染器），默认为AccelerateDecelerateInterpolator
也可通过setInterpolator设置；
AccelerateDecelerateInterpolator: 开始和结束时变化较慢，中间时候加速
An interpolator where the rate of change starts and ends slowly but accelerates through the middle
AccelerateInterpolator : 开始较慢，然后逐渐加速
An interpolator where the rate of change starts out slowly and and then accelerates.
AnticipateInterpolator ： 开始时向后，然后再向前急冲
An interpolator where the change starts backward then flings forward.
AnticipateOvershootInterpolator：开始时向后，然后再向前急冲一定值之后，最后回到最终值
An interpolator where the change starts backward then flings forward and overshoots the target value and finally goes back to the final value.
BounceInterpolator ： 动画结束时弹起
An interpolator where the change bounces at the end.
DecelerateInterpolator ; 开始时速度较快，然后减速
An interpolator where the rate of change starts out quickly and and then decelerates.
LinearInterpolator ; 变化速度为常量
An interpolator where the rate of change is constant
OvershootInterpolator ; 开始向前急冲，超过最终值，然后返回
An interpolator where the change flings forward and overshoots the last value then comes back.
三、添加动画监听器 AnimationListener
animation.setAnimationListener(new AnimationListener() { @Override public void onAnimationStart(Animation animation) { Log.i("AnimationListener", "动画开始"); } @Override public void onAnimationRepeat(Animation animation) { Log.i("AnimationListener", "动画重复"); } @Override public void onAnimationEnd(Animation animation) { Log.i("AnimationListener", "动画结束"); } });四、为ViewGroup添加动画
布局动画LayoutAnimation:
1、在res/anim下创建xml文件：layout_anim.xml
<?xmlversion="1.0"encoding="utf-8"?><layoutAnimation xmlns:android="http://schemas.android.com/apk/res/android" android:delay="1.0" android:animationOrder="random" android:animation="@anim/anim_set" /> <!-- delay 子类动画时间间隔（延迟） --><!-- animationOrder 子类的显示方式: normal(0 默认) reverse(1 倒序) random(2 随机) --><!-- animation : 对应动画 -->
2、使用：在activity的layout界面布局中写入：
android:layoutAnimation="@anim/layout_anim"
3、在Java代码中使用：
<为ListView（ViewGroup的子类）添加动画>
String[] mMenuItemStr = { "Bear", "Bird", "Cat", "Tigers", "Panda" ,"Bear", "Bird", "Cat", "Tigers", "Panda"}; listView.setAdapter(new ArrayAdapter<String>(this, R.layout.item_left_menu,mMenuItemStr)); Animation animation = AnimationUtils.loadAnimation(this, R.anim.anim_set); LayoutAnimationController controller = new LayoutAnimationController(animation); controller.setOrder(LayoutAnimationController.ORDER_NORMAL); controller.setDelay(1); listView.setLayoutAnimation(controller);4、实现效果是为ViewGroup中每一个子View添加了动画，并按照Random等方式进行加载
5、ViewGroup第一次进行布局时加载布局动画。可以通过listView.scheduleLayoutAnimation();强制其再次执行
6、添加动画监听：
listView.setLayoutAnimationListener(new AnimationListener() { @Override publicvoid onAnimationStart(Animation animation) { } @Override publicvoid onAnimationRepeat(Animation animation) { } @Override publicvoid onAnimationEnd(Animation animation) { } });五、拓展：
1、现有两个补间动画(anim1.xml,anim2.xml)，如何做到两个补间动画在一个播放完后就立刻播放另一个动画。
使用动画监听，重写onAnimationEnd方法即可
private Animation animation1, animation2; privateclass myAnimationListener implements AnimationListener { @Override publicvoid onAnimationStart(Animation animation) { } @Override publicvoid onAnimationEnd(Animation animation) { if(animation.hashCode() == animation1.hashCode()) myImageView.startAnimation(animation2); else myImageView.startAnimation(animation1); } @Override publicvoid onAnimationRepeat(Animation animation) { } }在Activity中使用得：
animation1 = AnimationUtils.loadAnimation(MainActivity.this, R.anim.anim1); animation2 = AnimationUtils.loadAnimation(MainActivity.this, R.anim.anim2); myAnimationListener myAnimationListener = new myAnimationListener(); animation1.setAnimationListener(myAnimationListener); animation2.setAnimationListener(myAnimationListener); myImageView.startAnimation(animation1);
2、自定义动画渲染器interpolator
private class myInterpolator implements Interpolator { @Override public float getInterpolation(floatinput) { /**input: 取值范围 0.0-1.0,表示动画的加载进度 * 返回值：<1.0表示还未达到目标点；越接近1.0表示离目标点越近；大于1.0表示动画对象已经超过了目标点**/ if(input <= 0.5) return input * input; else return (1 - input) * (1 - input); } }在代码中使用：
Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.anim1); animation.setInterpolator(new myInterpolator()); myImageView.startAnimation(animation);
对比看一下AccelerateInterpolator的源码：
/** * An interpolator where the rate of change starts out slowly and * and then accelerates. * */@HasNativeInterpolatorpublic class AccelerateInterpolator implements Interpolator, NativeInterpolatorFactory { private final floatmFactor; private final doublemDoubleFactor; public AccelerateInterpolator() { mFactor = 1.0f; mDoubleFactor = 2.0; } /** * Constructor * * @param factor Degree to which the animation should be eased. Seting * factor to 1.0f produces a y=x^2 parabola. Increasing factor above * 1.0f exaggerates the ease-in effect (i.e., it starts even * slower and ends evens faster) */ public AccelerateInterpolator(floatfactor) { mFactor = factor; mDoubleFactor = 2 * mFactor; } public AccelerateInterpolator(Context context, AttributeSet attrs) { this(context.getResources(), context.getTheme(), attrs); } /** @hide */ public AccelerateInterpolator(Resources res, Theme theme, AttributeSet attrs) { TypedArray a; if (theme != null) { a = theme.obtainStyledAttributes(attrs, R.styleable.AccelerateInterpolator, 0, 0); } else { a = res.obtainAttributes(attrs, R.styleable.AccelerateInterpolator); } mFactor = a.getFloat(R.styleable.AccelerateInterpolator_factor, 1.0f); mDoubleFactor = 2 * mFactor; a.recycle(); } public float getInterpolation(float input) { if (mFactor == 1.0f) { return input * input; } else { return (float)Math.pow(input, mDoubleFactor); } } /** @hide */ @Override public long createNativeInterpolator() { return NativeInterpolatorFactoryHelper.createAccelerateInterpolator(mFactor); }}