安卓開發的監聽事件

爲按鈕設置監聽事件分情況

1；

有多個按鈕，一個按鈕綁定一個事件。

import  java.view.view.OnClickListener;

searchworld.setOnClickListener(new listener());

public class listener implements OnClickListener{
public void onClick(View view)
{
String result=null;
String sql="select chinese from t_words where english=?";

Cursor cursor=database.rawQuery(sql, new String[]{word.getText().toString()});
if(cursor.getCount()>0)
{

cursor.moveToFirst();
result=cursor.getString(cursor.getColumnIndex("chinese")).replace("&", "&");


}

showResult.setText(word.getText()+"\n"+result.toString());

}

}

2.多個按鈕，但是隻用一個監聽事件。

在android應用程序中，有時要用到很多的按鈕元件，每個按鈕都要有一個監聽事件，爲了讓代碼看起來乾淨簡潔，並節省一些內存，我們可以用一個監聽器（Listener）來實現多個按鈕的onClick監聽，下面是一個具體的例子：

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:[phone]"));
            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:[phone]"));
    		startActivity(dial);
    		break;
    	case 3:
    		Intent wallpaper = new Intent(Intent.ACTION_SET_WALLPAPER);
            startActivity(Intent.createChooser(wallpaper, "Select Wallpaper"));
    		break;
    	default :
    		break;
    	}

    }
}

這段代碼用三個按鈕實現了三個Intent意圖：音樂播放、自動撥號、背景選擇。只用了一個onClick處理，這樣代碼看起來簡潔了很多。