点击事件产生后，发生了什么

• 点击事件产生后，事件的传递时这样的顺序:Activity->Window->View;
• 顶层View接收到事件后，会按照事件分发机制来分发事件；

ViewGroup的事件传递过程

• 事件传递给顶层View后，会调用VIewGroup的 dispatchTouchEvent方法；如果返回true，那么事件就会由ViewGroup处理；如果返回false，事件会传递给所在的点击事件链上的子View；子View的dispatchTouchEvent方法会被调用。
• ViewGroup在调用dispatchTouchEvent方法后，会调用到注释1 处的onInterceptTouchEvent方法，返回true，表示会拦截事件，默认是返回false；
• intercepted 方法返回true，注释2处 的代码块不会被执行；该代码块中，会遍历子View，最终调用到子View的dispatchEvent方法，详情如注释3；

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
    ......
            // 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); // 注释1.
                    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;
            }

......
            boolean alreadyDispatchedToNewTouchTarget = false;
            if (!canceled && !intercepted) {// 注释2
            ···
                                        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);
                            // 注释3，调用子View的dispatchEvent方法
                            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;
                                }
            }
···
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View对点击事件的处理

• View和VIewGroup之前的差异，View的点击事件是自己处理，无法往下传递；
  ####分析
• 1.判断时候设置了onTouchListener，如果onTouchListener的onTouch方法返回了true，那么注释1处的onTouchEvent方法就不会被调用；所以View的onTouchListener的优先级是高于onTouchEvent方法的;
• 2.view的属性设置了clickable或者longClickable，那么就会消耗点击事件，如图注释2；
• 3.在action_up事件发生时，会出发performClick方法，如果view设置了onclickListener，则会调用onClick方法，如图注释4；

    public boolean dispatchTouchEvent(MotionEvent event) {
            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;
           }
   		// 注释1
           if (!result && onTouchEvent(event)) {
               result = true;
           }
       }

       if (!result && mInputEventConsistencyVerifier != null) {
           mInputEventConsistencyVerifier.onUnhandledEvent(event, 0);
       }
       
public boolean onTouchEvent(MotionEvent event) {
       final float x = event.getX();
       final float y = event.getY();
       final int viewFlags = mViewFlags;
       final int action = event.getAction();

   	// 注释2；
       final boolean clickable = ((viewFlags & CLICKABLE) == CLICKABLE
               || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)
               || (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE;

       if ((viewFlags & ENABLED_MASK) == DISABLED
               && (mPrivateFlags4 & PFLAG4_ALLOW_CLICK_WHEN_DISABLED) == 0) {
           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;
           }
       }
     if (clickable || (viewFlags & TOOLTIP) == TOOLTIP) {
           switch (action) {
               case MotionEvent.ACTION_UP:
          ......
                               if (mPerformClick == null) {
                               // 注释3
                                   mPerformClick = new PerformClick();
                               }
                               if (!post(mPerformClick)) {
                                   performClickInternal();
                               }
                           }
                       }
}


   public boolean performClick() {
       // We still need to call this method to handle the cases where performClick() was called
       // externally, instead of through performClickInternal()
       notifyAutofillManagerOnClick();

       final boolean result;
       final ListenerInfo li = mListenerInfo;
       if (li != null && li.mOnClickListener != null) {
       // 注释4
           playSoundEffect(SoundEffectConstants.CLICK);
           li.mOnClickListener.onClick(this);
           result = true;
       } else {
           result = false;
       }

       sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);

       notifyEnterOrExitForAutoFillIfNeeded(true);

       return result;
   } 
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以上就是VIewGroup和View事件传递部分代码的简单分析；