Android自定义View实现可展开、会呼吸的按钮

int mBackgroundRectFLeft;
RectF mBackgroundRectF = new RectF();

@Override
protected void onDraw(Canvas canvas) {
 mBackgroundRectF.set(mBackgroundRectFLeft, 0, getWidth(), getHeight());
 canvas.drawRoundRect(mBackgroundRectF, mOuterRadius, mOuterRadius, mmBackgroundRectPaint);//圆角背景矩形
}

private void openButton() {
 ValueAnimator rectLeftAnim = ValueAnimator.ofInt(mBackgroundRectFLeft, mArcWidth / 2);
 rectLeftAnim.setDuration(250);
 ValueAnimator textAlphaAnim = ValueAnimator.ofInt(0, mItemTextAlpha);
 textAlphaAnim.setDuration(120);
 rectLeftAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
 @Override
 public void onAnimationUpdate(ValueAnimator animation) {
  mBackgroundRectFLeft = (int) animation.getAnimatedValue();
  invalidate();
 }
 });
}

mBreatheRadius = getHeight() / 2 - mArcWidth / 4;
mBreatheAnim = ValueAnimator.ofFloat(mBreatheRadius, mBreatheRadius - mArcWidth / 2);
mBreatheAnim.setDuration(1000);
mBreatheAnim.setRepeatMode(ValueAnimator.REVERSE);
mBreatheAnim.setRepeatCount(Integer.MAX_VALUE);
mBreatheAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
 @Override
 public void onAnimationUpdate(ValueAnimator animation) {
 mBreatheRadius = (float) animation.getAnimatedValue();
 invalidate();
 }
});
mBreatheAnim.start();

@Override
protected void onDraw(Canvas canvas) {
 canvas.drawCircle(mInnerCircleCenterX, mInnerCircleCenterY, mBreatheRadius, mBreathePaint);//呼吸圈

paint.getTextBounds(text, 0, text.length(), mTextRect);
int textWidth = mTextRect.width();
int textHeight = mTextRect.height();

float buttonTextWidth = mButtonTextPaint.measureText(mButtonStr, 0, mButtonStr.length());

Paint.FontMetrics publishFontMetrics = mButtonTextPaint.getFontMetrics();
canvas.drawText(mButtonStr, 0, mButtonStr.length(), getWidth() - mOuterRadius - mArcWidth / 2 - buttonTextWidth / 2, mOuterRadius + mArcWidth / 2 + -(publishFontMetrics.ascent + publishFontMetrics.descent) / 2, mButtonTextPaint);

@Override
public boolean onTouchEvent(MotionEvent event) {
 switch (event.getAction()) {
 case MotionEvent.ACTION_DOWN:
  x = (int) event.getX();
  y = (int) event.getY();
  if (!isOpen && x < getWidth() - 2 * mOuterRadius && y > 0 && y < getHeight()) {
  //未展开状态下，点击发布圆左侧的位置，不处理事件
  return false;
  }
  break;
 }
}