1.设置监听器

//frameworks\base\core\java\android\view\View.java
public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {/*** Register a callback to be invoked when this view is clicked. If this view is not* clickable, it becomes clickable.** @param l The callback that will run** @see #setClickable(boolean)* 如果一开始这个view无法点击的话，会设置成可点击*/public void setOnClickListener(@Nullable OnClickListener l) {if (!isClickable()) {setClickable(true);}getListenerInfo().mOnClickListener = l;}
}

2.View.dispatchTouchEvent

public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {public boolean dispatchTouchEvent(MotionEvent event) {//省略代码if (onFilterTouchEventForSecurity(event)) {//noinspection SimplifiableIfStatementListenerInfo li = mListenerInfo;if (li != null && li.mOnTouchListener != null&& (mViewFlags & ENABLED_MASK) == ENABLED&& li.mOnTouchListener.onTouch(this, event)) {//执行mOnTouchListener//如果执行mOnTouchListener.onTouch返回true，就不会再执行onTouchEventresult = true;}if (!result && onTouchEvent(event)) {//执行onTouchEventresult = true;}}//省略代码}
}

3.View.onTouchEvent 

MotionEvent.ACTION_UP 触发点击事件

public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {public boolean onTouchEvent(MotionEvent event) {final int action = event.getAction();if (((viewFlags & CLICKABLE) == CLICKABLE ||(viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) ||(viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE) {switch (action) {case MotionEvent.ACTION_UP:if (!post(mPerformClick)) { performClick();}}}}
}

4.View.post

public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {private PerformClick mPerformClick;public boolean post(Runnable action) {final AttachInfo attachInfo = mAttachInfo;if (attachInfo != null) {return attachInfo.mHandler.post(action);}// Assume that post will succeed laterViewRootImpl.getRunQueue().post(action);return true;}private final class PerformClick implements Runnable {@Overridepublic void run() {performClick();}}
}

5.View.performClick 

public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {/*** Call this view's OnClickListener, if it is defined.  Performs all normal* actions associated with clicking: reporting accessibility event, playing* a sound, etc.** @return True there was an assigned OnClickListener that was called, false*         otherwise is returned.*/public boolean performClick() {final boolean result;final ListenerInfo li = mListenerInfo;if (li != null && li.mOnClickListener != null) {playSoundEffect(SoundEffectConstants.CLICK);li.mOnClickListener.onClick(this);  //执行点击事件result = true;} else {result = false;}sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);return result;}
}