拍照按钮的动画

动画一　简单实现

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/bg_btn_white" />
    <item
        android:bottom="20.0dip"
        android:drawable="@drawable/ic_shutter_24dp"
        android:left="20.0dip"
        android:right="20.0dip"
        android:top="20.0dip" />
</layer-list>

mShutterButton.setImageResource(R.drawable.photo_shutter_button);

动画二　复杂实现：

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/shutter_button_pressed"
    android:oneshot="true" >

    <item
        android:drawable="@drawable/shutter_button_0"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_1"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_2"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_3"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_4"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_5"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_6"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_5"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_4"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_3"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_2"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_1"
        android:duration="33"/>
    <item
        android:drawable="@drawable/shutter_button_0"
        android:duration="33"/>

</animation-list>

 mShutterButton.setImageResource(R.drawable.shutter_button_anim);
        mShutterButton.setOnClickListener(new OnClickListener()
        {
            @Override
            public void onClick(View v) {
                    doShutterAnimation();         
        });

public void doShutterAnimation() {
    AnimationDrawable frameAnimation = (AnimationDrawable) mShutterButton.getDrawable();
    frameAnimation.stop();
    frameAnimation.start();
}