android 实现水波扩散效果

动图我也不会放 效果就是一层一层扩散.

代码如下.

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="250dp"
    android:id="@+id/ll_card"
    android:background="@color/orange"
    android:orientation="vertical">
    <!--中间的imageView-->
    <ImageView
        android:id="@+id/iv_wave_1"
        android:layout_width="170dp"
        android:layout_height="150dp"
        android:layout_gravity="center"
        android:background="@drawable/shape_circle" />
    <!--最外层imageView-->
    <ImageView
        android:id="@+id/iv_wave_2"
        android:layout_width="170dp"
        android:layout_height="150dp"
        android:layout_gravity="center"
        android:background="@drawable/shape_circle" />
    <!--中心imageView-->
    <ImageView
        android:id="@+id/iv_wave"
        android:layout_width="170dp"
        android:layout_height="150dp"
        android:layout_gravity="center"
        android:background="@drawable/shape_circle"/>
</FrameLayout>

在activity中加入以下代码:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setSupportActionBar(toolbar);
    setContentView(R.layout.activity_main);
    iv1 = (ImageView)findViewById(R.id.iv_wave_1);
    iv2 = (ImageView)findViewById(R.id.iv_wave_2);
    setAnim1();
    setAnim2();
}

private void setAnim1() {
    AnimationSet as = new AnimationSet(true);
    //缩放动画，以中心从原始放大到1.4倍
    ScaleAnimation scaleAnimation = new ScaleAnimation(1.0f, 1.4f, 1.0f, 1.4f,
            ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
            ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
    //渐变动画
    AlphaAnimation alphaAnimation = new AlphaAnimation(1.0f, 0.5f);
    scaleAnimation.setDuration(800);
    scaleAnimation.setRepeatCount(Animation.INFINITE);
    alphaAnimation.setRepeatCount(Animation.INFINITE);
    as.setDuration(800);
    as.addAnimation(scaleAnimation);
    as.addAnimation(alphaAnimation);
    iv1.startAnimation(as);
}
private void setAnim2() {
    AnimationSet as = new AnimationSet(true);
    //缩放动画，以中心从1.4倍放大到1.8倍
    ScaleAnimation scaleAnimation = new ScaleAnimation(1.4f, 1.8f, 1.4f, 1.8f,
            ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
            ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
    //渐变动画
    AlphaAnimation alphaAnimation = new AlphaAnimation(0.5f, 0.1f);
    scaleAnimation.setDuration(800);
    scaleAnimation.setRepeatCount(Animation.INFINITE);
    alphaAnimation.setRepeatCount(Animation.INFINITE);
    as.setDuration(800);
    as.addAnimation(scaleAnimation);
    as.addAnimation(alphaAnimation);
    iv2.startAnimation(as);
}