안 드 로 이 드 시스템 에서 응용 프로그램 앞 배경 전환 의 실현 요점 을 깊이 분석 하 다.

@Override 
  protected void onStop() { 
  // TODO Auto-generated method stub 
  　　super.onStop(); 
  　　Log.v("BACKGROUND", "      "); 
  　　showNotification(); 
  } 

//   HOME           
 
  @Override 
 
  public boolean onKeyDown(int keyCode, KeyEvent event) { 
 
    // TODO Auto-generated method stub 
 
    //   HOME  
 
    if(keyCode == KeyEvent.KEYCODE_HOME){ 
 
      //   Notification 
 
      notification = new NotificationExtend(this); 
 
      notification.showNotification(); 
 
      moveTaskToBack(true);         

      return true; 
 
    } 
 
    return super.onKeyDown(keyCode, event); 
 
  } 

package com.test.background; 

import android.app.Activity; 
 
import android.app.Notification; 
 
import android.app.NotificationManager; 
 
import android.app.PendingIntent; 
 
import android.content.Intent; 
 
import android.graphics.Color; 

/** 
 * Notification    
 * @Description: Notification    
 * @File: NotificationExtend.java 
 * @Package com.test.background 
 */ 
 
public class NotificationExtend { 
 
  private Activity context; 

  public NotificationExtend(Activity context) { 
 
    // TODO Auto-generated constructor stub 
 
    this.context = context; 
 
  } 
 
  //   Notification 
 
  public void showNotification() { 
 
    //     NotificationManager    
 
    NotificationManager notificationManager = ( 
 
        NotificationManager)context.getSystemService( 
 
            android.content.Context.NOTIFICATION_SERVICE); 
 
    //   Notification      
 
    Notification notification = new Notification( 
 
        R.drawable.icon,"   ",  
 
        System.currentTimeMillis()); 
 
    //           "Ongoing" "    "   
 
    notification.flags |= Notification.FLAG_ONGOING_EVENT; 
 
    //            "    " ，       。 
 
    notification.flags |= Notification.FLAG_AUTO_CANCEL 
 
    notification.flags |= Notification.FLAG_SHOW_LIGHTS; 
 
    notification.defaults = Notification.DEFAULT_LIGHTS; 
 
    notification.ledARGB = Color.BLUE; 
 
    notification.ledOnMS = 5000; 

    //           
 
    CharSequence contentTitle = "       "; //       
 
    CharSequence contentText = "      ，   ……"; //       

    Intent notificationIntent = new Intent(context,context.getClass()); 
 
    notificationIntent.setAction(Intent.ACTION_MAIN); 
    notificationIntent.addCategory(Intent.CATEGORY_LAUNCHER); 
    PendingIntent contentIntent = PendingIntent.getActivity( 
    context, 0, notificationIntent,PendingIntent.FLAG_UPDATE_CURRENT); 
    notification.setLatestEventInfo( 
    context, contentTitle, contentText, contentIntent); 
    //  Notification   NotificationManager 
    notificationManager.notify(0, notification); 
 
  } 

  //      
 
  public void cancelNotification(){ 
 
    NotificationManager notificationManager = ( 
 
        NotificationManager) context.getSystemService( 
 
            android.content.Context.NOTIFICATION_SERVICE); 
 
    notificationManager.cancel(0); 
 
  } 
 
} 

<activity android:name="ShowMessageActivity" 
       android:launchMode="singleTask"></activity>  

public class MyApplication extends Application{ 
  public int count = 0; 
  @Override 
  public void onCreate() { 
    super.onCreate(); 
 
    registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() { 
 
      @Override 
      public void onActivityStopped(Activity activity) { 
        Log.v("viclee", activity + "onActivityStopped"); 
        count--; 
        if (count == 0) { 
          Log.v("viclee", ">>>>>>>>>>>>>>>>>>>     lifecycle"); 
        } 
      } 
 
      @Override 
      public void onActivityStarted(Activity activity) { 
        Log.v("viclee", activity + "onActivityStarted"); 
        if (count == 0) { 
          Log.v("viclee", ">>>>>>>>>>>>>>>>>>>     lifecycle"); 
        } 
        count++; 
      } 
 
      @Override 
      public void onActivitySaveInstanceState(Activity activity, Bundle outState) { 
        Log.v("viclee", activity + "onActivitySaveInstanceState"); 
      } 
 
      @Override 
      public void onActivityResumed(Activity activity) { 
        Log.v("viclee", activity + "onActivityResumed"); 
      } 
 
      @Override 
      public void onActivityPaused(Activity activity) { 
        Log.v("viclee", activity + "onActivityPaused"); 
      } 
 
      @Override 
      public void onActivityDestroyed(Activity activity) { 
        Log.v("viclee", activity + "onActivityDestroyed"); 
      } 
 
      @Override 
      public void onActivityCreated(Activity activity, Bundle savedInstanceState) { 
        Log.v("viclee", activity + "onActivityCreated"); 
      } 
    }); 
  } 
} 

//               
 private boolean isCurrentRunningForeground = true; 
 @Override 
 protected void onStart() { 
   super.onStart(); 
   if (!isCurrentRunningForeground) { 
     Log.d(TAG, ">>>>>>>>>>>>>>>>>>>     activity process"); 
   } 
 } 
 
 @Override 
 protected void onStop() { 
   super.onStop(); 
   isCurrentRunningForeground = isRunningForeground(); 
   if (!isCurrentRunningForeground) { 
     Log.d(TAG,">>>>>>>>>>>>>>>>>>>     activity process"); 
   } 
 } 
 
 public boolean isRunningForeground() { 
   ActivityManager activityManager = (ActivityManager) this.getSystemService(Context.ACTIVITY_SERVICE); 
   List<ActivityManager.RunningAppProcessInfo> appProcessInfos = activityManager.getRunningAppProcesses(); 
   //      
   for (ActivityManager.RunningAppProcessInfo appProcessInfo : appProcessInfos) { 
     if (appProcessInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) { 
       if (appProcessInfo.processName.equals(this.getApplicationInfo().processName)) { 
         Log.d(TAG,"EntryActivity isRunningForeGround"); 
         return true; 
       } 
     } 
   } 
   Log.d(TAG, "EntryActivity isRunningBackGround"); 
   return false; 
 }