Android事件分发机制（下） View的事件处理

public boolean dispatchTouchEvent(MotionEvent event) {

  ......

  if (onFilterTouchEventForSecurity(event)) {
    //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;
    }
  }

  ......

  return result;
}

public interface OnTouchListener {
  boolean onTouch(View v, MotionEvent event);
}

public void setOnTouchListener(OnTouchListener l) {
  getListenerInfo().mOnTouchListener = l;
}

ListenerInfo getListenerInfo() {
  if (mListenerInfo != null) {
    return mListenerInfo;
  }
  mListenerInfo = new ListenerInfo();
  return mListenerInfo;
}

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);
}

public void setOnClickListener(@Nullable OnClickListener l) {
  if (!isClickable()) {
    setClickable(true);
  }
  getListenerInfo().mOnClickListener = l;
}

public void setOnLongClickListener(@Nullable OnLongClickListener l) {
  if (!isLongClickable()) {
    setLongClickable(true);
  }
  getListenerInfo().mOnLongClickListener = l;
}

public void setOnContextClickListener(@Nullable OnContextClickListener l) {
  if (!isContextClickable()) {
    setContextClickable(true);
  }
  getListenerInfo().mOnContextClickListener = l;
}

　　下面接着看OnTouchEvent里面代码。

if (mTouchDelegate != null) {
  if (mTouchDelegate.onTouchEvent(event)) {
    return true;
  }
}

if (((viewFlags & CLICKABLE) == CLICKABLE ||
    (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) ||
    (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE) {
  switch (action) {
    case MotionEvent.ACTION_UP:

      ......

        if (!mHasPerformedLongPress && !mIgnoreNextUpEvent) {
          // This is a tap, so remove the longpress check
          removeLongPressCallback();

          // Only perform take click actions if we were in the pressed state
          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();
            }
          }
        }

      ......

      break;

    ......

  }

  return true;
}

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;
}