/** 点击按钮消失动画 */
private void vanishOnBtnClick(int type) {
synchronized (obj1) {
View animateView = viewList.get(0);
if (animateView.getVisibility() != View.VISIBLE || releasedViewList.contains(animateView)) {
return;
}
int finalX = 0;
if (type == VANISH_TYPE_LEFT) {
finalX = -childWith;
} else if (type == VANISH_TYPE_RIGHT) {
finalX = allWidth;
}
if (finalX != 0) {
releasedViewList.add(animateView);
if (mDragHelper.smoothSlideViewTo(animateView, finalX, initCenterViewY + allHeight)) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
if (type >= 0 && cardSwitchListener != null) {
cardSwitchListener.onCardVanish(isShowing, type);
}
}
}
/**
* 松手时处理滑动到边缘的动画
*
* @param xvel X方向上的滑动速度
*/
private void animToSide(View changedView, float xvel, float yvel) {
int finalX = initCenterViewX;
int finalY = initCenterViewY;
int flyType = -1;
// 1. 下面这一坨计算finalX和finalY，要读懂代码需要建立一个比较清晰的数学模型才能理解，不信拉倒
int dx = changedView.getLeft() - initCenterViewX;
int dy = changedView.getTop() - initCenterViewY;
if (dx == 0) {
// 由于dx作为分母，此处保护处理
dx = 1;
}
if (xvel > X_VEL_THRESHOLD || dx > X_DISTANCE_THRESHOLD) {
finalX = allWidth;
finalY = dy * (childWith + initCenterViewX) / dx + initCenterViewY;
flyType = VANISH_TYPE_RIGHT;
} else if (xvel < -X_VEL_THRESHOLD || dx < -X_DISTANCE_THRESHOLD) {
finalX = -childWith;
finalY = dy * (childWith + initCenterViewX) / (-dx) + dy + initCenterViewY;
flyType = VANISH_TYPE_LEFT;
}
// 如果斜率太高，就折中处理
if (finalY > allHeight) {
finalY = allHeight;
} else if (finalY < -allHeight / 2) {
finalY = -allHeight / 2;
}
// 如果没有飞向两侧，而是回到了中间，需要谨慎处理
if (finalX != initCenterViewX) {
releasedViewList.add(changedView);
}
// 2. 启动动画
if (mDragHelper.smoothSlideViewTo(changedView, finalX, finalY)) {
ViewCompat.postInvalidateOnAnimation(this);
}
// 3. 消失动画即将进行，listener回调
if (flyType >= 0 && cardSwitchListener != null) {
cardSwitchListener.onCardVanish(isShowing, flyType);
}
}
