接下来，会进入第三阶段的工作：
final boolean canceled = resetCancelNextUpFlag(this) || actionMasked == MotionEvent.ACTION_CANCEL;
final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0;
TouchTarget newTouchTarget = null;
boolean alreadyDispatchedToNewTouchTarget = false;
if (!canceled && !intercepted) {
// 不是ACTION_CANCEL并且不拦截
if (actionMasked == MotionEvent.ACTION_DOWN) {
// 若当前事件为ACTION_DOWN则去寻找这次事件新出现的touch target
final int actionIndex = ev.getActionIndex(); // always 0 for down
...
final int childrenCount = mChildrenCount;
if (newTouchTarget == null && childrenCount != 0) {
// 根据触摸的坐标寻找能够接收这个事件的touch target
final float x = ev.getX(actionIndex);
final float y = ev.getY(actionIndex);
final View[] children = mChildren;
// 遍历所有子View
for (int i = childrenCount - 1; i >= 0; i--) {
final int childIndex = i;
final View child = children[childIndex];
// 寻找可接收这个事件并且touch事件坐标在其区域内的子View
if (!canViewReceivePointerEvents(child) || !isTransformedTouchPointInView(x, y, child, null)) {
continue;
}
newTouchTarget = getTouchTarget(child); // 找到了符合条件的子View，赋值给newTouchTarget
if (newTouchTarget != null) {
//Child is already receiving touch within its bounds.
//Give it the new pointer in addition to ones it is handling.
newTouchTarget.pointerIdBits |= idBitsToAssign;
break;
}
resetCancelNextUpFlag(child);
// 把ACTION_DOWN事件传递给子组件进行处理
if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) {
//Child wants to receive touch within its bounds.
mLastTouchDownTime = ev.getDownTime();
if (preorderedList != null) {
//childIndex points into presorted list, find original index
for (int j=0;j<childrenCount;j++) {
if (children[childIndex]==mChildren[j]) {
mLastTouchDownIndex=j;
break;
}
}
} else {
mLastTouchDownIndex = childIndex;
}
mLastTouchDownX = ev.getX();
mLastTouchDownY = ev.getY();
//把mFirstTouchTarget赋值为newTouchTarget，此子View成为新的touch事件的起点
newTouchTarget = addTouchTarget(child, idBitsToAssign);
alreadyDispatchedToNewTouchTarget = true;
break;
}
}
}
}
}
