@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (!onFilterTouchEventForSecurity(ev)) {
return false;
}
//獲取當前的動作
final int action = ev.getAction();
final float xf = ev.getX();
final float yf = ev.getY();
//獲取view的正確的坐標
final float scrolledXFloat = xf + mScrollX;
final float scrolledYFloat = yf + mScrollY;
final Rect frame = mTempRect;
//判斷是否設(shè)置不攔截的標志
boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;
//將mMotionTarget置為null
if (action == MotionEvent.ACTION_DOWN) {
if (mMotionTarget != null) {
// this is weird, we got a pen down, but we thought it was
// already down!
// XXX: We should probably send an ACTION_UP to the current
// target.``
mMotionTarget = null;
}
//disallowIntercept=true就表示不允許攔截，進入，disallowIntercept 可以通過viewGroup.requestDisallowInterceptTouchEvent(boolean);進行設(shè)置是否攔截而onInterceptTouchEvent(ev)我們可以復(fù)寫自己控制返回值！
// intercept
if (disallowIntercept || !onInterceptTouchEvent(ev)) {
// reset this event's action (just to protect ourselves)
ev.setAction(MotionEvent.ACTION_DOWN);
// We know we want to dispatch the event down, find a child
// who can handle it, start with the front-most child.
final int scrolledXInt = (int) scrolledXFloat;
final int scrolledYInt = (int) scrolledYFloat;
final View[] children = mChildren;
final int count = mChildrenCount;
//開始遍歷子view注意這個遍歷是倒著遍歷的因為最后添加的view肯定在最上面！child.dispatchTouchEvent(ev)
for (int i = count - 1; i >= 0; i--) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE
|| child.getAnimation() != null) {
child.getHitRect(frame);
//進行判斷當前點擊的坐標是否包含子view如果包含這個子view就調(diào)用
if (frame.contains(scrolledXInt, scrolledYInt)) {
// offset the event to the view's coordinate system
final float xc = scrolledXFloat - child.mLeft;
final float yc = scrolledYFloat - child.mTop;
ev.setLocation(xc, yc);
child.mPrivateFlags &= ~CANCEL_NEXT_UP_EVENT;
//下面就是走view的事件分發(fā)流程了
if (child.dispatchTouchEvent(ev)) {
// Event handled, we have a target now.
mMotionTarget = child;
return true;
}
// The event didn't get handled, try the next view.
// Don't reset the event's location, it's not
// necessary here.
}
}
}
}
} //down中做的事情就是判斷是否需要攔截事件，如果不需要攔截就遍歷字view執(zhí)行view的分發(fā)
ViewGroup - dispatchTouchEvent - ACTION_UP
public boolean dispatchTouchEvent(MotionEvent ev) {
if (!onFilterTouchEventForSecurity(ev)) {
return false;
}
final int action = ev.getAction();
final float xf = ev.getX();
final float yf = ev.getY();
final float scrolledXFloat = xf + mScrollX;
final float scrolledYFloat = yf + mScrollY;
final Rect frame = mTempRect;
boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;
if (action == MotionEvent.ACTION_DOWN) {...}
boolean isUpOrCancel = (action == MotionEvent.ACTION_UP) ||
(action == MotionEvent.ACTION_CANCEL);
//判讀當前的事件是否等于up或者ACTION_CANCEL
if (isUpOrCancel) {
mGroupFlags &= ~FLAG_DISALLOW_INTERCEPT;
}
final View target = mMotionTarget;
if(target ==null ){...}
//判斷當前的view是否攔截
if (!disallowIntercept && onInterceptTouchEvent(ev)) {...}
if (isUpOrCancel) {
mMotionTarget = null;
}
// finally offset the event to the target's coordinate system and
// dispatch the event.
final float xc = scrolledXFloat - (float) target.mLeft;
final float yc = scrolledYFloat - (float) target.mTop;
ev.setLocation(xc, yc);
return target.dispatchTouchEvent(ev);
}
up的時候主要是重置一些屬性。然后在調(diào)用dispatchTouchEvent
