1.如果有触摸事件，首先会调用到Activity 的dispatchTouchEvent 方法。
public boolean dispatchTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_DOWN) {onUserInteraction();}if (getWindow().superDispatchTouchEvent(ev)) {return true;}return onTouchEvent(ev);}
getWindow().superDispatchTouchEvent 最终会调用PhoneWindow 的 superDispatchTouchEvent
@Overridepublic boolean superDispatchTouchEvent(MotionEvent event) {return mDecor.superDispatchTouchEvent(event);}
mDecor.superDispatchTouchEvent(event); 最终会调用到DecorView 类的 dispatchTouchEvent
2.然后我们来看DecorView.dispatchTouchEvent 是怎么写的。
因为DecorView 是 FrameLayout 的子类，所以，他的dispatchTouchEvent 代码在ViewGroup 类的dispatchTouchEvent （FrameLayout 里面是没有dispatchTouchEvent 这个方法的，所以在ViewGroup 里面），如下：
@Overridepublic boolean dispatchTouchEvent(MotionEvent ev) {****************boolean handled = false;if (onFilterTouchEventForSecurity(ev)) {final int action = ev.getAction();final int actionMasked = action & MotionEvent.ACTION_MASK;// Handle an initial down.if (actionMasked == MotionEvent.ACTION_DOWN) {// Throw away all previous state when starting a new touch gesture.// The framework may have dropped the up or cancel event for the previous gesture// due to an app switch, ANR, or some other state change.cancelAndClearTouchTargets(ev);resetTouchState();}// Check for interception.final boolean intercepted;if (actionMasked == MotionEvent.ACTION_DOWN|| mFirstTouchTarget != null) {final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;if (!disallowIntercept) {intercepted = onInterceptTouchEvent(ev);ev.setAction(action); // restore action in case it was changed} else {intercepted = false;}} else {// There are no touch targets and this action is not an initial down// so this view group continues to intercept touches.intercepted = true;}// If intercepted, start normal event dispatch. Also if there is already// a view that is handling the gesture, do normal event dispatch.if (intercepted || mFirstTouchTarget != null) {ev.setTargetAccessibilityFocus(false);}// Check for cancelation.final boolean canceled = resetCancelNextUpFlag(this)|| actionMasked == MotionEvent.ACTION_CANCEL;// Update list of touch targets for pointer down, if needed.final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0;TouchTarget newTouchTarget = null;boolean alreadyDispatchedToNewTouchTarget = false;if (!canceled && !intercepted) {// If the event is targeting accessibility focus we give it to the// view that has accessibility focus and if it does not handle it// we clear the flag and dispatch the event to all children as usual.// We are looking up the accessibility focused host to avoid keeping// state since these events are very rare.View childWithAccessibilityFocus = ev.isTargetAccessibilityFocus()? findChildWithAccessibilityFocus() : null;if (actionMasked == MotionEvent.ACTION_DOWN|| (split && actionMasked == MotionEvent.ACTION_POINTER_DOWN)|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {final int actionIndex = ev.getActionIndex(); // always 0 for downfinal int idBitsToAssign = split ? 1 << ev.getPointerId(actionIndex): TouchTarget.ALL_POINTER_IDS;// Clean up earlier touch targets for this pointer id in case they// have become out of sync.removePointersFromTouchTargets(idBitsToAssign);final int childrenCount = mChildrenCount;if (newTouchTarget == null && childrenCount != 0) {final float x = ev.getX(actionIndex);final float y = ev.getY(actionIndex);// Find a child that can receive the event.// Scan children from front to back.final ArrayList<View> preorderedList = buildTouchDispatchChildList();final boolean customOrder = preorderedList == null&& isChildrenDrawingOrderEnabled();final View[] children = mChildren;for (int i = childrenCount - 1; i >= 0; i--) {final int childIndex = getAndVerifyPreorderedIndex(childrenCount, i, customOrder);final View child = getAndVerifyPreorderedView(preorderedList, children, childIndex);// If there is a view that has accessibility focus we want it// to get the event first and if not handled we will perform a// normal dispatch. We may do a double iteration but this is// safer given the timeframe.if (childWithAccessibilityFocus != null) {if (childWithAccessibilityFocus != child) {continue;}childWithAccessibilityFocus = null;i = childrenCount - 1;}if (!canViewReceivePointerEvents(child)|| !isTransformedTouchPointInView(x, y, child, null)) {ev.setTargetAccessibilityFocus(false);continue;}newTouchTarget = getTouchTarget(child);if (newTouchTarget != null) {// Child is already receiving touch within its bounds.// Give it the new pointer in addition to the ones it is handling.newTouchTarget.pointerIdBits |= idBitsToAssign;break;}resetCancelNextUpFlag(child);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 indexfor (int j = 0; j < childrenCount; j++) {if (children[childIndex] == mChildren[j]) {mLastTouchDownIndex = j;break;}}} else {mLastTouchDownIndex = childIndex;}mLastTouchDownX = ev.getX();mLastTouchDownY = ev.getY();newTouchTarget = addTouchTarget(child, idBitsToAssign);alreadyDispatchedToNewTouchTarget = true;break;}// The accessibility focus didn't handle the event, so clear// the flag and do a normal dispatch to all children.ev.setTargetAccessibilityFocus(false);}if (preorderedList != null) preorderedList.clear();}if (newTouchTarget == null && mFirstTouchTarget != null) {// Did not find a child to receive the event.// Assign the pointer to the least recently added target.newTouchTarget = mFirstTouchTarget;while (newTouchTarget.next != null) {newTouchTarget = newTouchTarget.next;}newTouchTarget.pointerIdBits |= idBitsToAssign;}}}// Dispatch to touch targets.if (mFirstTouchTarget == null) {// No touch targets so treat this as an ordinary view.handled = dispatchTransformedTouchEvent(ev, canceled, null,TouchTarget.ALL_POINTER_IDS);} else {// Dispatch to touch targets, excluding the new touch target if we already// dispatched to it. Cancel touch targets if necessary.TouchTarget predecessor = null;TouchTarget target = mFirstTouchTarget;while (target != null) {final TouchTarget next = target.next;if (alreadyDispatchedToNewTouchTarget && target == newTouchTarget) {handled = true;} else {final boolean cancelChild = resetCancelNextUpFlag(target.child)|| intercepted;if (dispatchTransformedTouchEvent(ev, cancelChild,target.child, target.pointerIdBits)) {handled = true;}if (cancelChild) {if (predecessor == null) {mFirstTouchTarget = next;} else {predecessor.next = next;}target.recycle();target = next;continue;}}predecessor = target;target = next;}}// Update list of touch targets for pointer up or cancel, if needed.if (canceled|| actionMasked == MotionEvent.ACTION_UP|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {resetTouchState();} else if (split && actionMasked == MotionEvent.ACTION_POINTER_UP) {final int actionIndex = ev.getActionIndex();final int idBitsToRemove = 1 << ev.getPointerId(actionIndex);removePointersFromTouchTargets(idBitsToRemove);}}if (!handled && mInputEventConsistencyVerifier != null) {mInputEventConsistencyVerifier.onUnhandledEvent(ev, 1);}return handled;}
可能这个方法有点长，有点复杂，但是看懂这一段，就可以完全理解TouchEvent 事件传递机制。
3. dispatchTouchEvent 里面会去检查，当前的ViewGroup 是不是拦截 拦截事件
如果是的话，就不会遍历每个子View，也就是不会把事件传递给下一级。
// Check for interception.final boolean intercepted;if (actionMasked == MotionEvent.ACTION_DOWN|| mFirstTouchTarget != null) {final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;if (!disallowIntercept) {intercepted = onInterceptTouchEvent(ev);ev.setAction(action); // restore action in case it was changed} else {intercepted = false;}} else {// There are no touch targets and this action is not an initial down// so this view group continues to intercept touches.intercepted = true;}if (!canceled && !intercepted) { // 不拦截才回去走具体的分发给子view 的 touchEvent}
在这里面回到用onInterceptTouchEvent,但是不是所有的情况都会调用。是有判断的。如果当前是ActionDown，或者mFirstTouchTarget 不是空，那么再去判断有没有子View 调用过getParent().requestDisallowInterceptTouchEvent(true); 如果有子View 请求不要拦截，那么就不会再走onInterceptTouchEvent,否则还是会走onInterceptTouchevent.
4.如果不拦截就会走到这里：
if (!canceled && !intercepted) {final int childrenCount = mChildrenCount;if (newTouchTarget == null && childrenCount != 0) {final float x = ev.getX(actionIndex);final float y = ev.getY(actionIndex);final View[] children = mChildren;for (int i = childrenCount - 1; i >= 0; i--) {final int childIndex = getAndVerifyPreorderedIndex(childrenCount, i, customOrder);final View child = getAndVerifyPreorderedView(preorderedList, children, childIndex);// 如果当前事件的位置，不在子view 里面，那么就continueif (!canViewReceivePointerEvents(child)|| !isTransformedTouchPointInView(x, y, child, null)) {ev.setTargetAccessibilityFocus(false);continue;}newTouchTarget = getTouchTarget(child);//子view 再去分发给他的子viewif (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) { // 走到这里表示子view 是要处理的// Child wants to receive touch within its bounds.mLastTouchDownTime = ev.getDownTime();if (preorderedList != null) {// childIndex points into presorted list, find original indexfor (int j = 0; j < childrenCount; j++) {if (children[childIndex] == mChildren[j]) {mLastTouchDownIndex = j;break;}}} else {mLastTouchDownIndex = childIndex;}// 把要处理的view 加到mFirstTouchTarget 字段里newTouchTarget = addTouchTarget(child, idBitsToAssign);alreadyDispatchedToNewTouchTarget = true;break;}}}/*** Adds a touch target for specified child to the beginning of the list.* Assumes the target child is not already present.*/private TouchTarget addTouchTarget(@NonNull View child, int pointerIdBits) {final TouchTarget target = TouchTarget.obtain(child, pointerIdBits);target.next = mFirstTouchTarget;mFirstTouchTarget = target;return target;}
这里面会调用dispatchTransformedTouchEvent 方法。
4.dispatchTransformedTouchEvent 这个方法是个很重要的方法。
我们来看下他有一个参数是View child ，如果传递的参数的child 不是空，就会调用dispatchTouchEvent,继续往下传递。如果child是空只能说明一个问题，已经遍历到view 的最后一级了，已经没有子View 了。这时候就会调用super.dispatchTouchEvent方法. 调用super.dispatchTouchEvent 就会调用View 类的onTouchEvent。因为ViewGroup 也好，TextView 等也要，都是View 的子类。
/*** Transforms a motion event into the coordinate space of a particular child view,* filters out irrelevant pointer ids, and overrides its action if necessary.* If child is null, assumes the MotionEvent will be sent to this ViewGroup instead.*/private boolean dispatchTransformedTouchEvent(MotionEvent event, boolean cancel,View child, int desiredPointerIdBits) {final boolean handled;// Canceling motions is a special case. We don't need to perform any transformations// or filtering. The important part is the action, not the contents.final int oldAction = event.getAction();if (cancel || oldAction == MotionEvent.ACTION_CANCEL) {event.setAction(MotionEvent.ACTION_CANCEL);if (child == null) {handled = super.dispatchTouchEvent(event);} else {handled = child.dispatchTouchEvent(event);}event.setAction(oldAction);return handled;}if (newPointerIdBits == oldPointerIdBits) {if (child == null || child.hasIdentityMatrix()) {if (child == null) {handled = super.dispatchTouchEvent(event);} else {final float offsetX = mScrollX - child.mLeft;final float offsetY = mScrollY - child.mTop;event.offsetLocation(offsetX, offsetY);handled = child.dispatchTouchEvent(event);event.offsetLocation(-offsetX, -offsetY);}return handled;}transformedEvent = MotionEvent.obtain(event);} else {transformedEvent = event.split(newPointerIdBits);}// Perform any necessary transformations and dispatch.if (child == null) {handled = super.dispatchTouchEvent(transformedEvent);} else {final float offsetX = mScrollX - child.mLeft;final float offsetY = mScrollY - child.mTop;transformedEvent.offsetLocation(offsetX, offsetY);if (! child.hasIdentityMatrix()) {transformedEvent.transform(child.getInverseMatrix());}handled = child.dispatchTouchEvent(transformedEvent);}// Done.transformedEvent.recycle();return handled;}
View 类的dispatchTouchEvent。他会调用onTouchEvent,如下：
/*** Pass the touch screen motion event down to the target view, or this* view if it is the target.** @param event The motion event to be dispatched.* @return True if the event was handled by the view, false otherwise.*/public boolean dispatchTouchEvent(MotionEvent event) {boolean result = false;if (onFilterTouchEventForSecurity(event)) {if ((mViewFlags & ENABLED_MASK) == ENABLED && handleScrollBarDragging(event)) {result = true;}if (!result && onTouchEvent(event)) {result = true;}}if (!result && mInputEventConsistencyVerifier != null) {mInputEventConsistencyVerifier.onUnhandledEvent(event, 0);}// Clean up after nested scrolls if this is the end of a gesture;// also cancel it if we tried an ACTION_DOWN but we didn't want the rest// of the gesture.if (actionMasked == MotionEvent.ACTION_UP ||actionMasked == MotionEvent.ACTION_CANCEL ||(actionMasked == MotionEvent.ACTION_DOWN && !result)) {stopNestedScroll();}return result;}
5.如果某一个view dispatchTouchEvent 或者onTouch 返回了true, 那么就会把这个View 记录在当前ViewGroup 的mFirstTouchTarget 字段里面。
以后每次分发Action Move, Action up 都不会再去遍历查找要处理Touch事件的View. 直接使用mFirstTouchTarget.
if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) { newTouchTarget = addTouchTarget(child, idBitsToAssign);}
6.如果最底层的view 的onTouchEvent依然不处理，那么就不会记录到mFirstTouchTarget 字段里面。
然后方法会继续执行到dispatchTransformedTouchEvent(ev, canceled, null,
TouchTarget.ALL_POINTER_IDS);，因为这里的child 传递的是null，所以会调用onTouchEvent.
如果也不处理，代码会继续走到父View 的onTouchEvent, 看看处理不处理。
// Dispatch to touch targets.if (mFirstTouchTarget == null) {// No touch targets so treat this as an ordinary view.handled = dispatchTransformedTouchEvent(ev, canceled, null,TouchTarget.ALL_POINTER_IDS);
如果都不处理，那么最后会执行到Activity 的 onTouchEvent，如下：
public boolean dispatchTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_DOWN) {onUserInteraction();}if (getWindow().superDispatchTouchEvent(ev)) {return true;}return onTouchEvent(ev);}
具体流程：
收到ACTION_DOWN 事件的时候
首先执行最外层ViewGroup 的dispatchTouchEvent，然后执行onInterceptTouchEvent，看看自己拦截不拦截，如果拦截，直接执行当前ViewGroup 的OnTouchEvent，看看自己处理不处理，并把结果返回给Parent.
如果不拦截，遍历循环子View，如果子veiw 是 ViewGroup 类型的，那么调用子View 的dispatchTouchEvent， 继续调用子View 的 onInterceptTouchEvent，如果拦截，就直接执行当前ViewGroup的OnTouchEvent。并把结果返给Parent. ，如果不拦截的话，如果这个ViewGroup 还有子view,那么就继续往下传递。如果子View 是View类型，在dispatchTouchEvent 里面 会首先判断当前View 有没有设置onTouchListener,如果有那么看一下
onTouchListener 返回true 还是false，如果返回true 表示这个onTouchListener要处理事件，否则的话，表示不处理。就会继续走View 的onTouchEvent 方法。
直至view 树的最后一个View，如果最后这个view dispatchTouchEvent onTouchEvent 都不返回true 的话，（不处理的），然后就开始返回到parent。执行到父view 的 dispatchTouchEvent方法里面， 因为子View 不处理，mFirstTouchTarget 就是空的，所以会调用到父View 的 onTouchEvent，看看父View 处理不处理，有些ViewGroup 是自己处理TouchEvent的，比如ScrollView. 可以看到ScrollView 的onTouchEvent 方法恒返回true. 如果父View 的onTouchEvent也不处理，就执行父父View dispatchTouchEvent, 以此类推。
最后都不执行，就执行Activity 的OnTouchEvent.
当收到ACTION_MOVE 事件的时候
ViewGroup 会判断mFirstTouchTarget 是不是空，如果是空表示没有人处理这次的点击事件，那么就不再调用onInterceptTouchEvent，直接调用自己的onTouchEvent.
如果当前ViewGroup 的mFirstTouchTarget 不是空，首先判断一下子View 有没有调用过getParent().requestDisallowInterceptTouchEvent(true); 如果没有子View 调用过这个方法，那么会走onInterceptTouchEvent方法，看一下自己是不是拦截，如果自己拦截，那么就发送Action_Cancle 给mFirstTouchEvent。然后自己处理剩下的事件，比如ScrollView.如果自己的onInterceptTouchEvent 不拦截，那么把事件传递给mFirestTouchTarget 处理。如果mFirestTouchTarget 表示，ACTION_MOVE，我也不处理，但是整个调用链上没有任何parent 拦截的话，之后的ACTION_MOVE 还是会发送给mFirestTouchTarget 处理。
当收到Action_Up 的时候
如果ViewGroup 的mFirstTouchTarget 是不是空，如果是空，那么调用自己的onTouchEvent.如果ViewGroup 的mFirstTouchTarget 不是空的话，就会走当前ViewGroup 的onInterceptTouchEvent，看一下自己不是拦截，如果拦截，那么就发送Action_Cancle 给mFirstTouchTarget.mFirestTouchTarget 又会用用样的方式，传递给他的mFirestTouchTarget.直到完成。
1.ACTION_DOWN ViewGroup 寻找哪个子View来处理这个事件，找到了放到mFirstTouchTarget里面。形成一条调用链。
2.ACTION_MOVE 的时候，如果子view 没有调用requestDisallowInterecptTouchEvent，那么继续走ViewGroup的onInterceptToucheEvent.看看自己拦不拦截。如果不拦截，那么看看mFirstTouchTarget 是不是空，如果不是空，那么传递给mFirstTouchTarge，否则调用自己的onTouchEvent。这一步不再进行分发，如果你想要在move 的时候继续判断用户手势上下决定要不要处理事件，那么你就要在ActionDown的时候，就要返回True，你才能接受之后的事件，当你判断用户手势自己要处理的时候，那么调用requestDisallowInterecptTouchEvent，告诉父亲都不要拦截我的事件了。
3.如果这时候ViewGroup拦截了，那么分发cancle给mFristTouchTarget。否则的话，就按正常的调用链传递
总结：
1.下载aosp 调试之后，才永远都了解事件传递机制。否则的话，只能看别人说，也看不懂源码，最终面试都会忘记。
2.下载了源码，可以调试就是爽。加油吧。为了我的媳妇。
资料：
以下为调用堆栈截图：
可以看到会循环view 调用dispatchTouchEvent
调用具体堆栈：
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2679)at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3048)at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2677)at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3048)at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2677)at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3048)at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2677)at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3048)at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2677)at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3048)at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2677)at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:440)at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1830)at android.app.Activity.dispatchTouchEvent(Activity.java:3437)at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:69)at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:398)at android.view.View.dispatchPointerEvent(View.java:12833)at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5146)at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4949)at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4452)at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4505)at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4471)at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4611)at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4479)at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4668)at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4452)at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4505)at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4471)at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4479)at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4452)at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7143)at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7112)at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7073)at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7246)at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:189)at android.os.MessageQueue.nativePollOnce(MessageQueue.java:-1)at android.os.MessageQueue.next(MessageQueue.java:326)at android.os.Looper.loop(Looper.java:160)at android.app.ActivityThread.main(ActivityThread.java:6743)at java.lang.reflect.Method.invoke(Method.java:-1)at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:486)at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:882)
问：如果已经有View 表示处理touchEvent，那么onInterceptTouchEvent 还会调用吗？
会！
// Check for interception.final boolean intercepted;if (actionMasked == MotionEvent.ACTION_DOWN|| mFirstTouchTarget != null) {final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;if (!disallowIntercept) {intercepted = onInterceptTouchEvent(ev);ev.setAction(action); // restore action in case it was changed} else {intercepted = false;}} else {// There are no touch targets and this action is not an initial down// so this view group continues to intercept touches.intercepted = true;}
上面这段代码，如果event 已经有view 处理，那么mFirstTouchTarget 就不会null,那么就会走onInterceptTouchEvent。所以，就算当时已经有view处理，如果没有调用getParent().requestDisallowInterceptTouchEvent(true); 还是可以拦截的。
如何打印mFirstTouchTarget ？
Object mFirstTouchTarget = Util.getField(this, "mFirstTouchTarget");Log.e("ViewShelfHeadParent= onInterceptTouchEvent ", mFirstTouchTarget != null ? Util.getField(mFirstTouchTarget, "child").getClass().getSimpleName():"null");
为什么我的View onInterceptTouchEvent 只走了一次？
如果发生了onTouchDown,在传递链中的一个的View返回了true,在这个传递链往后的View onTouchEvent 都没有返回true.那么之后的move事件，从这个View 往后都不会在收到。dispatchTouchEvent 也不会再走。onInterceptTouchEvent.同样因为后面的分发就不会再走你了。因为你既不是ACTION_DOWN，mFirstTouchTarget 又是null.那么之后，你的父View你根本不再传递链里面。
View 的 mOnTouchListener先调用 还是onTouchEvent 先调用？
肯定是mOnTouchListener 先调用，如果mOnTouchListener 不处理才调用自己的onTouchEvent 的。不然mOnTouchListener 什么时候处理？ ouTouchEvent 处理完再处理？那你设置Listener 还有啥用?
具体代码是：android.view.View#dispatchTouchEvent
public boolean dispatchTouchEvent(MotionEvent event) {// If the event should be handled by accessibility focus first.if (event.isTargetAccessibilityFocus()) {// We don't have focus or no virtual descendant has it, do not handle the event.if (!isAccessibilityFocusedViewOrHost()) {return false;}// We have focus and got the event, then use normal event dispatch.event.setTargetAccessibilityFocus(false);}boolean result = false;if (mInputEventConsistencyVerifier != null) {mInputEventConsistencyVerifier.onTouchEvent(event, 0);}final int actionMasked = event.getActionMasked();if (actionMasked == MotionEvent.ACTION_DOWN) {// Defensive cleanup for new gesturestopNestedScroll();}if (onFilterTouchEventForSecurity(event)) {if ((mViewFlags & ENABLED_MASK) == ENABLED && handleScrollBarDragging(event)) {result = true;}//noinspection SimplifiableIfStatementListenerInfo li = mListenerInfo;if (li != null && li.mOnTouchListener != null&& (mViewFlags & ENABLED_MASK) == ENABLED&& li.mOnTouchListener.onTouch(this, event)) {result = true;}if (!result && onTouchEvent(event)) {result = true;}}
怎么处理滑动冲突？
在父容器的onInterceptTouchEvent 里面，判断action_move 的时候，父容器处不处理，如果处理，那么就返回true，拦截时间，否则返回false 就行了。
如果你在返回true 的时候，记得调用parent.requestDisallowInterceptTouchEvent这是一个好习惯。
当然你也可以在子view 里面处理。不建议在子view 里面处理，因为父view 一个地方就可以处理，子view处理的话，父view 还是要判断什么情况自己处理。
可以去看下ListView，ScrollView 等，都是只在onInterceptTouchEvent 处理，简单清晰。
参考：/A/1O5E9ZYn57/
View 的OnClickListener 是怎么执行的？
如果一个view的onTouchEvent 返回true. 在ACTION_DOWN的时候，会postDelayed 一个 500ms 的Runnable，用来执行长按事件。然后在ACTION_UP的时候，去判断一下，这个mOnLongClickListener 是不是执行了，如果执行了mOnLongClickListener ，那么说明是长按事件，就不再调用mOnClickListener。否则执行onClick. 如果说长按已经超过了500ms，那么就会直接执行onLongClick.
(可以看View 的onTouch 方法，一般是clickable 的话，就直接返回true了),那么在Action_down 的时候，就会返回true
如果一个View 是disabled ， 但是clickAble 是true ，他会消费事件吗？
public boolean onTouchEvent(MotionEvent event) {final float x = event.getX();final float y = event.getY();final int viewFlags = mViewFlags;final int action = event.getAction();final boolean clickable = ((viewFlags & CLICKABLE) == CLICKABLE|| (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)|| (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE;if ((viewFlags & ENABLED_MASK) == DISABLED) {if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {setPressed(false);}mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;// A disabled view that is clickable still consumes the touch// events, it just doesn't respond to them.return clickable;}if (mTouchDelegate != null) {if (mTouchDelegate.onTouchEvent(event)) {return true;}}
会的，看下面代码：
if ((viewFlags & ENABLED_MASK) == DISABLED) {if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {setPressed(false);}mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;// A disabled view that is clickable still consumes the touch// events, it just doesn't respond to them.return clickable;}
如果试试disable 的，但是你clickable 的话，那么这个view 还是会消费事件，不过不会真的调用View 的具体的onTouch
问题：
如果我重写了一个View 的长按事件，当发生长按后，在当前的View 上面叠加一层frameLayout,那么,当我滑动或者手指抬起的时候，这个View 会收到事件吗？
会。
