android View事件分發實測

剛剛翻出了多年前的筆記，是我實戰測試View事件分發的結果。

主要測試dispatchTouchEvent、onInterceptTouchEvent和onTouchEvent方法調用流程。

為了時刻拿出來複習，決定發出來，與大家分享。

demo附件：DespatchTouchDemo.rar

源碼

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<com.example.despatchtouchdemo.MLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.example.despatchtouchdemo.MTextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="match_parent text"
        android:textSize="30dp" />

</com.example.despatchtouchdemo.MLinearLayout>           

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MainActivity.java

package com.example.despatchtouchdemo;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    
    public void textClick(View v){
        Toast.makeText(this, "textClick", 1).show();
    }
    
    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        Log.i("i", "MainActivity ---> dispatchTouchEvent = super; --->" + Util.getActionString(ev));
        return super.dispatchTouchEvent(ev);
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        Log.i("i", "MainActivity ---> onTouchEvent = super; --->" + Util.getActionString(event));
        return super.onTouchEvent(event);
    }
}           

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MLinearLayout.java

package com.example.despatchtouchdemo;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.LinearLayout;

public class MLinearLayout extends LinearLayout {

    public MLinearLayout(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    
    public MLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        Log.i("i", "MLinearLayout ---> dispatchTouchEvent = super; --->" + Util.getActionString(ev));
        return super.dispatchTouchEvent(ev);
    }
    
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        Log.i("i", "MLinearLayout ---> onInterceptTouchEvent = false; --->" + Util.getActionString(ev));
//        return super.onInterceptTouchEvent(ev);
        return false;
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        Log.i("i", "MLinearLayout ---> onTouchEvent = true; --->" + Util.getActionString(event));
//        return super.onTouchEvent(event);
        return true;
    }
    
    
    
}           

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MTextView.java

package com.example.despatchtouchdemo;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.TextView;

public class MTextView extends TextView {

    public MTextView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }
    
    public MTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    public MTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // TODO Auto-generated constructor stub
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        Log.i("i", "MTextView ---> dispatchTouchEvent = super; --->" + Util.getActionString(event));
        return super.dispatchTouchEvent(event);
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        Log.i("i", "MTextView ---> onTouchEvent = false; --->" + Util.getActionString(event));
//        return super.onTouchEvent(event);
        return false;
    }

}           

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Util.java

package com.example.despatchtouchdemo;

import android.view.MotionEvent;

public class Util {
    
    public static String getActionString(MotionEvent ev){
        String action = "";
        switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            action = "ACTION_DOWN";
            break;
        case MotionEvent.ACTION_MOVE:
            action = "ACTION_MOVE";
            break;
        case MotionEvent.ACTION_UP:
            action = "ACTION_UP";
            break;
        default:
            break;
        }
        
        return action;
    }

}           

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測試結果

為了指代友善，下面将MLinearLayout簡稱為L，将MTextView簡稱為 T，L.onInterceptTouchEvent=true 表示的含義為MLinearLayout中的onInterceptTouchEvent方法傳回值為true，通過程式運作時輸出的Log來說明調用 時序。

所有方法的傳回值都傳回super，結果如下：

第1種情況 L.onInterceptTouchEvent=false&& L.onTouchEvent=true &&T.onTouchEvent=true 輸出下面的Log

第2種情況 L.onInterceptTouchEvent=false&& L.onTouchEvent=true &&T.onTouchEvent=false 輸出下面的Log：

第3種情況 L.onInterceptTouchEvent=true&& L.onTouchEvent=true 輸出下面的Log：

第4種情況 L.onInterceptTouchEvent=true&& L.onTouchEvent=false 輸出下面的Log：

（标簽：android、View、事件分發）