Frame Animation

简介

Frame Animation, 逐帧动画，通过定义一系列的Drawable对象来实现动画效果，可以用来作为视图的背景。
Frame Animation在代码中体现为AnimationDrawable对象，可以通过xml文件快创建，放在在/res/drawable/目录下，设置为视图背景后，调用start()方法即可执行逐帧动画。

XML文件

Tags:
< animation-list > 作为父节点，代表Animation Drawable
< item >作为子节点，代表逐帧动画内容，一张一张图片

Attributes:

Res:
/res/drawable/{folder}

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/selected"
    android:oneshot="true"
    android:variablePadding="false"
    android:visible="true">

    <item android:drawable="@drawable/ic_action_add" android:duration="500"/>
    <item android:drawable="@drawable/ic_action_anchor" android:duration="500"/>
    <item android:drawable="@drawable/ic_action_alarm" android:duration="500"/>
    <item android:drawable="@drawable/ic_action_amazon" android:duration="500"/>
    <item android:drawable="@drawable/ic_action_ac" android:duration="500"/>

</animation-list>

Coding

使用XML资源

imageView.setBackgroundResource(R.drawable.frame_anim);//设置背景
Drawable bgDrawable = imageView.getBackground();//获取背景
if(bgDrawable instanceof AnimationDrawable) {
    ((AnimationDrawable) bgDrawable).start();//如果为AnimationDrawable则执行动画
}

纯代码实现

***
imageView.setBackground(createAnimationDrawable());//设置背景
Drawable bg = imageView.getBackground();
if(bg instanceof AnimationDrawable) {
    ((AnimationDrawable) bg).start();//开始动画
}

***
private AnimationDrawable createAnimationDrawable() {

    AnimationDrawable animationDrawable = new AnimationDrawable();
    animationDrawable.addFrame(getResources().getDrawable(R.drawable.ic_action_add), 500);
    animationDrawable.addFrame(getResources().getDrawable(R.drawable.ic_action_anchor), 500);
    animationDrawable.addFrame(getResources().getDrawable(R.drawable.ic_action_alarm), 500);
    animationDrawable.addFrame(getResources().getDrawable(R.drawable.ic_action_amazon), 500);
    animationDrawable.addFrame(getResources().getDrawable(R.drawable.ic_action_ac), 500);
    animationDrawable.setOneShot(false);
    animationDrawable.setVisible(true,true);
    return animationDrawable;
}

效果图