Android实现水波纹扩散效果

本文实例为大家分享了Android实现水波纹扩散效果的具体代码，供大家参考，具体内容如下

先上图

囧！没有图片所以就拿了小安代替了。

先看一下如何使用这个View。

<jianpan.com.mybutton.view.RippleDiffuse
 android:layout_width="200dp"
 android:layout_height="200dp"
 app:btn_img_res="@drawable/rd"
 app:ripple_img_res="@drawable/rd">
</jianpan.com.mybutton.view.RippleDiffuse>

是的，没有别的代码了，就这么简单

实现思路

自定义ViewGroup，创建一个用显示图片的view，在创建几个，大小相同的ImageView。当按下时，对这几个ImageView进行放大和渐变。

代码

首先它肯定是一个正方形。

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 super.onMeasure(widthMeasureSpec, widthMeasureSpec);
 if (!mInitDataSucceed){
 initData();
 }
}

显示图片的View的大小，该怎么给？这是个比较蛋疼的问题。给大了就看不到扩散效果了，给小，给多少的值合适呢？有没有正好的值，有的用父 view 的 size / 子 view 放大的倍数，这样肯定会达到理想的效果。

private static final int ANIMATION_EACH_OFFSET = 800; // 每个动画的播放时间间隔
private static final int RIPPLE_VIEW_COUNT = 3;//波纹view的个数
private static final float DEFAULT_SCALE = 1.6f;//波纹放大后的大小

//点击有扩散效果的view
private CircleImageView mBtnImg;
private int mBtnViewHeight;
private int mBtnViewWidth;
private float mScale = DEFAULT_SCALE;
//图片资源
private int mBtnImgRes;
private int mRippleRes;
//是否初始化完成
private boolean mInitDataSucceed = false;

private void initData(){
 if (getMeasuredHeight() > 0 && getMeasuredWidth() > 0){
 mInitDataSucceed = true;

 int height = getMeasuredHeight() - getPaddingTop() - getPaddingBottom();
 int width = getMeasuredWidth() - getPaddingLeft() - getPaddingRight();
 mBtnViewHeight = (int) (height / mScale);
 mBtnViewWidth = (int) (width / mScale);

 mBtnImg = new CircleImageView(getContext());
 mBtnImg.setImageResource(mBtnImgRes);
 mBtnImg.setOnTouchListener(this);

 addView(mBtnImg, getWaveLayoutParams());

 for (int i = 0; i < RIPPLE_VIEW_COUNT; i++){
  //创建view
  CircleImageView wave = createWave();
  mWaves.add(wave);
  //创建动画
  mAnimas.add(getNewAnimationSet());

  addView(wave, 0, getWaveLayoutParams());
 }
 }
}
private CircleImageView createWave(){
 CircleImageView CircleImageView = new CircleImageView(getContext());
 CircleImageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
 CircleImageView.setImageResource(mRippleRes);
 return CircleImageView;
}

private LayoutParams getWaveLayoutParams(){
 LayoutParams lp = new LayoutParams(mBtnViewWidth, mBtnViewHeight);
 return lp;
}

private AnimationSet getNewAnimationSet() {
 AnimationSet as = new AnimationSet(true);
 ScaleAnimation sa = new ScaleAnimation(1f, mScale, 1f, mScale,
  ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
  ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
 sa.setDuration(ANIMATION_EACH_OFFSET * 3);
 sa.setRepeatCount(-1);// 设置循环
 AlphaAnimation aniAlp = new AlphaAnimation(1, 0.1f);
 aniAlp.setRepeatCount(-1);// 设置循环
 as.setDuration(ANIMATION_EACH_OFFSET * 3);
 as.addAnimation(sa);
 as.addAnimation(aniAlp);
 return as;
}

View 都初始化完成了，好像还差一步，onLayout，只要把子 View 都显示到中先就可以了。

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
 if (mInitDataSucceed) {
 int childLeft = (getMeasuredWidth() - mBtnViewWidth) / 2;
 int childTop = (getMeasuredHeight() - mBtnViewHeight) / 2;
 for (int i = 0; i < RIPPLE_VIEW_COUNT; i++) {
  CircleImageView wave = mWaves.get(i);
  wave.layout(childLeft, childTop, mBtnViewWidth + childLeft, mBtnViewHeight + childTop);
 }
 mBtnImg.layout(childLeft, childTop, mBtnViewWidth + childLeft, mBtnViewHeight + childTop);
 }else {
 initData();
 }
}

最后处理一下图片的onTouch事件。

@Override
public boolean onTouch(View v, MotionEvent event) {
 switch (event.getAction()) {
 case MotionEvent.ACTION_DOWN:
  showWaveAnimation();
  break;
 case MotionEvent.ACTION_MOVE:
  break;
 case MotionEvent.ACTION_UP:
 case MotionEvent.ACTION_CANCEL:
  cancelWaveAnimation();
  break;
 default:
  cancelWaveAnimation();
  break;
 }
 return true;
}

private void showWaveAnimation() {
 for (int i = 0; i < RIPPLE_VIEW_COUNT; i++){
 Message message = new Message();
 message.obj = i;
 handler.sendMessageDelayed(message, ANIMATION_EACH_OFFSET * i);
 }
}

private void cancelWaveAnimation() {
 for (int i = 0; i < RIPPLE_VIEW_COUNT; i++){
 CircleImageView wave = mWaves.get(i);
 wave.clearAnimation();
 }
}

private Handler handler = new Handler() {
 @Override
 public void handleMessage(Message msg) {
 int position = (int) msg.obj;
 CircleImageView wave = mWaves.get(position);
 wave.startAnimation(mAnimas.get(position));
 super.handleMessage(msg);
 }
};

参考地址：Android实现水波纹外扩效果

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