Android用一个监听器实现多个监听

在android应用程序中，有时要用到很多的按钮元件，没个按钮都要有一个监听事件，为了让代码看起来干净简洁，并节省一些内存，我们可以用一个监听器（Listener）来实现多个按钮的onClick监听下面是一个具有的例子：
[java] package com.android;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class IntentSelectActivity extends Activity implements View.OnClickListener{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button button1 = (Button)findViewById(R.id.btn1);
        Button button2 = (Button)findViewById(R.id.btn2);
        Button button3 = (Button)findViewById(R.id.btn3);
        button1.setOnClickListener(this);
        button1.setTag(1);
        button2.setOnClickListener(this);
        button2.setTag(2);
        button3.setOnClickListener(this);
        button3.setTag(3);


    }
    public void onClick(View v){
        int tag = (Integer) v.getTag();
        switch(tag){
        case 1:
            Intent music = new Intent(Intent.ACTION_GET_CONTENT);
            music.setType("audio/*");
            startActivity(Intent.createChooser(music, "Select music"));
            break;
        case 2:
            Intent dial = new Intent();
            dial.setAction("android.intent.action.CALL");
            dial.setData(Uri.parse("tel:13428720000"));
            startActivity(dial);
            break;
        case 3:
            Intent wallpaper = new Intent(Intent.ACTION_SET_WALLPAPER);
            startActivity(Intent.createChooser(wallpaper, "Select Wallpaper"));
            break;
        default :
            break;
        }

    }
}
package com.android;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class IntentSelectActivity extends Activity implements View.OnClickListener{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button button1 = (Button)findViewById(R.id.btn1);
        Button button2 = (Button)findViewById(R.id.btn2);
        Button button3 = (Button)findViewById(R.id.btn3);
        button1.setOnClickListener(this);
        button1.setTag(1);
        button2.setOnClickListener(this);
        button2.setTag(2);
        button3.setOnClickListener(this);
        button3.setTag(3);

    }
    public void onClick(View v){
    int tag = (Integer) v.getTag();
    switch(tag){
    case 1:
            Intent music = new Intent(Intent.ACTION_GET_CONTENT);
            music.setType("audio/*");
            startActivity(Intent.createChooser(music, "Select music"));
      break;
    case 2:
      Intent dial = new Intent();
      dial.setAction("android.intent.action.CALL");
      dial.setData(Uri.parse("tel:13428720000"));
      startActivity(dial);
      break;
    case 3:
      Intent wallpaper = new Intent(Intent.ACTION_SET_WALLPAPER);
            startActivity(Intent.createChooser(wallpaper, "Select Wallpaper"));
      break;
    default :
      break;
    }

}
}

这段代码用三个按钮实现了三个Intent意图：音乐播放、自动拨号、背景选择。只用了一个onClick处理，这样代码看起来简洁了很多。

备注，Intent的属性写法与常数写法：

属性写法
Intent dial = new Intent();
dial.setAction("android.intent.action.CALL");
常数写法 www.zzzyk.com
Intent wallpaper = new Intent(Intent.ACTION_SET_WALLPAPER);
Intent music = new Intent(Intent.ACTION_GET_CONTENT);
在Intent类中，定义了action的常数。在记忆技巧上，可以用 xxx对应到ACTION_xxx 的方式记。例如：

CALL（android.intent.action.CALL）就是ACTION_CALL（Intent.ACTION_CALL）。

程序运行效果为：

摘自 Young的专栏

补充：移动开发 , Android ,