Android学习之使用SharedPreferences存储应用程序数据

/* 
 * @author:conowen 
 * @date:12.3.01 
 * 
 */ 
package com.conowen.sharedpreferences; 
 
import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
 
public class SharedPreferencesActivity extends Activity { 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    Button play = (Button) findViewById(R.id.play);  
    Button pause = (Button) findViewById(R.id.pause);  
  
    final Intent intent = new Intent(SharedPreferencesActivity.this,service.class);  
    // 定义intent为final，全局变量，供下面两个匿名内部类（onclicklisenter）使用  
    play.setOnClickListener(new OnClickListener() {  
  
      @Override  
      public void onClick(View v) {  
        // TODO Auto-generated method stub  
        startService(intent);  
        // 开始播放，通过前面定义好的intent传递  
  
      }  
    });  
    pause.setOnClickListener(new OnClickListener() {  
  
      @Override  
      public void onClick(View v) {  
        // TODO Auto-generated method stub  
        stopService(intent);  
        // 停止播放  
  
      }  
    });  
     
  } 
} 

 /* 
 * @author:conowen 
 * @date:12.3.01 
 * 
 */ 
package com.conowen.sharedpreferences; 
 
import android.app.Service; 
import android.content.Intent; 
import android.content.SharedPreferences; 
import android.media.MediaPlayer; 
import android.os.IBinder; 
 
public class service extends Service { 
 
  MediaPlayer player; 
 
  // 新建播放器 
 
  @Override 
  public void onCreate() { 
    // TODO Auto-generated method stub 
    super.onCreate(); 
    player = MediaPlayer.create(this, R.raw.lt26); 
    player.setLooping(true); 
    // 两种方式的第一个生命周期都是onCreate（） 
  } 
 
  @Override 
  public void onStart(Intent intent, int startId) { 
    // TODO Auto-generated method stub 
    super.onStart(intent, startId); 
    SharedPreferences sp = this.getSharedPreferences("music_progress", 
        MODE_PRIVATE); 
    // music_progress为XML文件的文件名 
    player.seekTo(sp.getInt("progress", 0)); 
    // progress为键值对中的key，progress所对应的值通过player.getCurrentPosition()获得，请看下面详细 
    // 每次调用onStart方法时，就会设置player的进度 
    // MediaPlayer的seekTo方法，读取进度，然后播放，getInt的第一个参数是所要读取的key名字，第二个参数为默认初始值。也就是说进度初始默认为0 
    player.start(); 
  } 
 
  @Override 
  public void onDestroy() { 
    // TODO Auto-generated method stub 
    super.onDestroy(); 
    SharedPreferences sp = this.getSharedPreferences("music_progress", 
        MODE_PRIVATE); 
    sp.edit().putInt("progress", player.getCurrentPosition()).commit(); 
    // player.getCurrentPosition()方法获取播放进度的数据 
    // commit()方法是保存SharedPreferences获取来的数据 
    player.stop(); 
  } 
 
  @Override 
  public IBinder onBind(Intent intent) { 
    // TODO Auto-generated method stub 
    return null; 
  } 
 
} 

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