View的事件分发（附流程图）

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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>

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