View的事件分发（附流程图）

View的事件分发：

1、  触摸事件的传递流程是从dispatchTouchEvent开始的，如果不进行人为干预（super.dispatchTouchEvent()），则事件会按照嵌套层次从外层依次向内层传递，到达最内层View时，就由它的TouchEvent方法处理。该方法如果能消费此事件，则返回true，如果处理不了，则返回false，这时事件会重新向外层传递，并由外层view的touchevetnt方法进行处理，以此类推。如果进行人为干预，无论返回true或false，都不再向下传递。

2、  如果事件在向内层传递过程中进行人为干预，处理函数返回true，则会导致事件提前被消费掉，内层view将不会收到此事件

3、  View控件的事件触发顺序是先执行onTouch方法，在最后才执行onClick方法。如果OnTouch返回true，则事件不会继续传递，最后也不会调用onclick方法，如果onTouch返回false，则事件继续传递。

package com.lantier.xxb_student.firstapp; import android.content.Context; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.widget.TextView; /** * Created by xxb_student on 2017/6/7. */ public class MyTextView extends TextView { private static final String TAG = "MyTextView"; public MyTextView(Context context) { super(context); } public MyTextView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); } public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()){ case MotionEvent.ACTION_DOWN: Log.e(TAG, "---->>onTouchEvent ACTION_DOWN: " ); break; case MotionEvent.ACTION_MOVE: Log.e(TAG, "---->>onTouchEvent ACTION_MOVE: " ); break; case MotionEvent.ACTION_UP: Log.e(TAG, "---->>onTouchEvent ACTION_UP: " ); break; } return true; } @Override public boolean dispatchTouchEvent(MotionEvent event) { switch (event.getAction()){ case MotionEvent.ACTION_DOWN: Log.e(TAG, "---->>dispatchTouchEvent ACTION_DOWN: " ); break; case MotionEvent.ACTION_MOVE: Log.e(TAG, "---->>dispatchTouchEvent ACTION_MOVE: " ); break; case MotionEvent.ACTION_UP: Log.e(TAG, "---->>dispatchTouchEvent ACTION_UP: " ); break; } return super.dispatchTouchEvent(event); }

}

package com.lantier.xxb_student.firstapp; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.MotionEvent; import android.view.View; public class TouchActivity extends AppCompatActivity implements View.OnTouchListener, View.OnClickListener{ private static final String TAG = "TouchActivity"; private MyTextView tvTest; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_touch); initView(); } private void initView() { tvTest = (MyTextView) findViewById(R.id.tv_test); tvTest.setOnClickListener(this); tvTest.setOnTouchListener(this); } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()){ case MotionEvent.ACTION_DOWN: Log.e(TAG, "---->>onTouchEvent ACTION_DOWN: " ); break; case MotionEvent.ACTION_MOVE: Log.e(TAG, "---->>onTouchEvent ACTION_MOVE: " ); break; case MotionEvent.ACTION_UP: Log.e(TAG, "---->>onTouchEvent ACTION_UP: " ); break; } return super.onTouchEvent(event); } @Override public boolean dispatchTouchEvent(MotionEvent event) { switch (event.getAction()){ case MotionEvent.ACTION_DOWN: Log.e(TAG, "---->>dispatchTouchEvent ACTION_DOWN: " ); break; case MotionEvent.ACTION_MOVE: Log.e(TAG, "---->>dispatchTouchEvent ACTION_MOVE: " ); break; case MotionEvent.ACTION_UP: Log.e(TAG, "---->>dispatchTouchEvent ACTION_UP: " ); break; } return super.dispatchTouchEvent(event); } @Override public boolean onTouch(View v, MotionEvent event) { switch (v.getId()){ case R.id.tv_test: switch (event.getAction()){ case MotionEvent.ACTION_DOWN: Log.e(TAG, "---->>tv_test onTouch ACTION_DOWN: " ); break; case MotionEvent.ACTION_MOVE: Log.e(TAG, "---->>tv_test onTouch ACTION_MOVE: " ); break; case MotionEvent.ACTION_UP: Log.e(TAG, "---->>tv_test onTouch ACTION_UP: " ); break; } break; } return false; } @Override public void onClick(View v) { switch (v.getId()){ case R.id.tv_test: Log.e(TAG, "---->>onClick:tv_test " ); break; } } }

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.lantier.xxb_student.firstapp.TouchActivity"> <com.lantier.xxb_student.firstapp.MyTextView android:id="@+id/tv_test" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="自定义TextView"/> </LinearLayout>