view中的getTag何setTag

 

 

View中的setTag（Onbect）表示给View添加一个格外的数据，以后可以用getTag()将这个数据取出来。

可以用在多个Button添加一个监听器，每个Button都设置不同的setTag。这个监听器就通过getTag来分辨是哪个Button 被按下。

   
   
import android.app.Activity;    
import android.os.Bundle;    
import android.view.View;    
import android.widget.Button;    
   
public class Main extends Activity {    
       
    @Override   
    public void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        setContentView(R.layout.main);    
        Button button1 = (Button) findViewById(R.id.Button01);    
        Button button2 = (Button) findViewById(R.id.Button02);    
        Button button3 = (Button) findViewById(R.id.Button03);    
        Button button4 = (Button) findViewById(R.id.Button04);    
        MyListener listener = new MyListener();    
        button1.setTag(1);    
        button1.setOnClickListener(listener);    
        button2.setTag(2);    
        button2.setOnClickListener(listener);    
        button3.setTag(3);    
        button3.setOnClickListener(listener);    
        button4.setTag(4);    
        button4.setOnClickListener(listener);    
    }    
   
    public class MyListener implements View.OnClickListener {    
   
        @Override   
        public void onClick(View v) {    
            int tag = (Integer) v.getTag();    
            switch (tag) {    
            case 1:    
                System.out.println("button1 click");    
                break;    
            case 2:    
                System.out.println("button2 click");    
                break;    
            case 3:    
                System.out.println("button3 click");    
                break;    
            case 4:    
                System.out.println("button4 click");    
                break;    
            }    
        }    
   
    }    
   
}