点击事件产生之后，最先传递给当前Activity，由Activity的dispatchTouchEvent进行分发。
public boolean dispatchTouchEvent(MotionEvent ev) { if (ev.getAction() == MotionEvent.ACTION_DOWN) { onUserInteraction(); } if (getWindow().superDispatchTouchEvent(ev)) { return true; } return onTouchEvent(ev); }很明显，Activity直接交由Window去分发，如果返回的是true，说明事件被处理了，事件就结束了；如果返回的是false，说明事件没有人处理，那么Activity就调用自己的onTouchEvent方法进行处理。
public abstract boolean superDispatchTouchEvent(MotionEvent event);跟进Window类可以看到，superDispatchTouchEvent是个抽象方法。
mWindow = new PhoneWindow(this);查找Activity的成员变量mWindow的初始化过程，发现mWindow是PhoneWindow对象。于是查看PhoneWindow类的superDispatchTouchEvent方法。
@Override public boolean superDispatchTouchEvent(MotionEvent event) { return mDecor.superDispatchTouchEvent(event); }这里PhoneWindow直接把点击事件交给mDecor进行分发。mDecor是一个DecorView对象，DecorView是window里的顶级View。在Activity里调用setContentView就是将layout的View设置为DecorView的子View。
public boolean superDispatchTouchEvent(MotionEvent event) { return super.dispatchTouchEvent(event); }而类DecorView继承自FrameLayout。superDispatchTouchEvent方法直接调用了父类的dispatchTouchEvent方法进行分发，即调用ViewGroup的dispatchTouchEvent方法。
ViewGroup接收到事件之后，如果不拦截，就继续向子View分发。如果拦截，则调用onTouchEvent对事件进行处理，ViewGroup是View的子类，ViewGroup本身是没有onTouchEvent方法的，调用的View的onTouchEvent方法，因此拦截之后对事件的处理逻辑和View是一致的。
先从dispatchTouchEvent看起，以下判断是否拦截的部分。
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; }这里要调用onInterceptTouchEvent判断是否拦截要先满足两个if的条件。
首先是事件类型为ACTION_DOWN或者mFirstTouchTarget!=null，从后面源码可以知道当有子View成功处理了该事件的时候会调用addTouchTarget方法将mFirstTouchTarget赋值为该子View，也就是说mFirstTouchTarget!=null意味着这一系列的点击事件的ACTION_DOWN已经有子View进行处理了。因此如果ViewGroup拦截了ACTION_DOWN，后续的ACTION_MOVE、ACTION_UP等事件就会直接交给ViewGroup处理。
第二个if是FLAG_DISALLOW_INTERCEPT标志位，可以调用requestDisallowInterceptTouchEvent方法设置了该标志位。按照源码，假设子View处理了一系列事件的ACTION_DOWN，这时候mFirstTouchTarget!=null，默认是会调用ViewGroup的onInterceptTouchEvent方法判断是否拦截后续的ACTION_MOVE、ACTION_UP等事件的，而子View可以通过设置FLAG_DISALLOW_INTERCEPT标志位来拒绝ViewGroup插手这一系列事件。
而对ACTION_DOWN事件无效，因为在ACTION_DOWN事件分发的时候，会重置该标志位。
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(); }在分发ACTION_DOWN事件时，清除了mFirstTouchTarget和mGroupFlags。
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 = buildOrderedChildList(); final boolean customOrder = preorderedList == null && isChildrenDrawingOrderEnabled(); final View[] children = mChildren; for (int i = childrenCount - 1; i >= 0; i--) { final int childIndex = customOrder ? getChildDrawingOrder(childrenCount, i) : i; final View child = (preorderedList == null) ? children[childIndex] : preorderedList.get(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 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(); 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(); }ViewGroup不拦截点击事件的时候，通过for循环遍历子View，通过canViewReceivePointerEvents和isTransformedTouchPointInView过滤掉不能接收事件的子View。canViewReceivePointerEvents判断View是否可见或者正在执行动画，isTransformedTouchPointInView判断点击是否在View的范围中，两个条件同时满足的View才可以接收到事件。
然后通过dispatchTransformedTouchEvent方法将事件分发到子View。
if (child == null) { handled = super.dispatchTouchEvent(transformedEvent); } else { ... handled = child.dispatchTouchEvent(transformedEvent); }dispatchTransformedTouchEvent方法返回子View的处理情况。如果如果子View已经处理，返回true，则走进if分支调用addTouchTarget。并将标志位alreadyDispatchedToNewTouchTarget赋值为true。
private TouchTarget addTouchTarget(@NonNull View child, int pointerIdBits) { final TouchTarget target = TouchTarget.obtain(child, pointerIdBits); target.next = mFirstTouchTarget; mFirstTouchTarget = target; return target; }将子View赋值给mFirstTouchTarget。
if (mFirstTouchTarget == null) { // No touch targets so treat this as an ordinary view. handled = dispatchTransformedTouchEvent(ev, canceled, null, TouchTarget.ALL_POINTER_IDS); } else {如果子View没有处理，调用dispatchTransformedTouchEvent(ev, canceled, null,TouchTarget.ALL_POINTER_IDS)方法，结合前面dispatchTransformedTouchEvent方法的代码可以知道当child为null时，调用super.dispatchTouchEvent方法，即View类的dispatchTouchEvent方法。强调一下，这个dispatchTouchEvent不是子View的方法，而是ViewGroup继承的View类的方法，因此这里是由ViewGroup处理事件。
从ViewGroup的dispatchTouchEvent方法分析可以知道，最后都会调用View类的dispatchTouchEvent方法进行处理。
public boolean dispatchTouchEvent(MotionEvent event) { boolean result = false; ... final int actionMasked = event.getActionMasked(); if (onFilterTouchEventForSecurity(event)) { if ((mViewFlags & ENABLED_MASK) == ENABLED && handleScrollBarDragging(event)) { result = true; } //noinspection SimplifiableIfStatement ListenerInfo 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; } } if (!result && mInputEventConsistencyVerifier != null) { mInputEventConsistencyVerifier.onUnhandledEvent(event, 0); } return result; }相对来说，View的dispatchTouchEvent方法比较短比较清晰。ListenerInfo是View中各种监听事件的聚合类，设置一些listener的时候就会初始化。
因此这里逻辑为：如果View设置了OnTouchListener，就先交给OnTouchListener处理，如果onTouchEvent返回true，就消费掉了事件。如果没有消费掉该事件，则调用View的onTouchEvent方法进行处理。接下来分段分析onTouchEvent的源码。
if ((viewFlags & ENABLED_MASK) == DISABLED) { if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) { setPressed(false); } // A disabled view that is clickable still consumes the touch // events, it just doesn't respond to them. return (((viewFlags & CLICKABLE) == CLICKABLE || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) || (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE); }从代码中可以看到，当View处于DISABLED状态时，如果CLICKABLE或LONG_CLICKABLE为true仍然会消费掉事件。
if (mTouchDelegate != null) { if (mTouchDelegate.onTouchEvent(event)) { return true; } }如果设置了代理，则交给代理处理，如果代理消费了事件，则返回true。否则继续往下走。
if (((viewFlags & CLICKABLE) == CLICKABLE || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) || (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE) { switch (action) { case MotionEvent.ACTION_UP: boolean prepressed = (mPrivateFlags & PFLAG_PREPRESSED) != 0; if ((mPrivateFlags & PFLAG_PRESSED) != 0 || prepressed) { ... if (!mHasPerformedLongPress && !mIgnoreNextUpEvent) { ... if (!focusTaken) { // Use a Runnable and post this rather than calling // performClick directly. This lets other visual state // of the view update before click actions start. if (mPerformClick == null) { mPerformClick = new PerformClick(); } if (!post(mPerformClick)) { performClick(); } } } ... } mIgnoreNextUpEvent = false; break; ... } return true; }如果CLICKABLE或者LONGCLICKABLE为true时，最后默认return true，即默认消费掉touch事件。在ACTION_UP中，会触发post(mPerformClick)。
private final class PerformClick implements Runnable { @Override public void run() { performClick(); } }PerformClick是Runnable的子类，run方法中调用了performClick方法。
public boolean performClick() { final boolean result; final ListenerInfo li = mListenerInfo; if (li != null && li.mOnClickListener != null) { playSoundEffect(SoundEffectConstants.CLICK); li.mOnClickListener.onClick(this); result = true; } else { result = false; } sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED); return result; }如果View设置了OnClickListener，则会调用onClick回调方法。
