在Android中查找广播接收器的运行活动

Question

我想从我的广播接收器中查找当前正在运行的其他活动。这是我从活动中使用它来查找其他运行activites但是当我尝试在我的广播接收器使用此代码我得到以下行错误代码：

ActivityManager am = (ActivityManager)this.getSystemService(ACTIVITY_SERVICE); 

显示在eclipse ACTIVITY_SERVICE误差不能解析为一个可变

PackageManager pm = this.getPackageManager(); 

，这表明在蚀该错误的方法getPackageManager（）是未定义的类型ScreenReceiver（我的广播接收机）

这里是全码：

public void getRunning(){ 
     ActivityManager am = (ActivityManager)this.getSystemService(ACTIVITY_SERVICE); 
     List l = am.getRunningAppProcesses(); 
     Iterator i = l.iterator(); 
     PackageManager pm = this.getPackageManager(); 
     while(i.hasNext()) { 
      ActivityManager.RunningAppProcessInfo info = (ActivityManager.RunningAppProcessInfo)(i.next()); 
      try { 
      CharSequence c = pm.getApplicationLabel(pm.getApplicationInfo(info.processName, PackageManager.GET_META_DATA)); 
      Log.w("LABEL", c.toString()); 
      runningApplications.add(c.toString()); 
      }catch(Exception e) { 
      //Name Not Found Exception 
      } 
     } 

    } 

Answer 1

由于广播接收器没有从上下文血统，你不能使用这个，你可以在活动做。您应该使用传递给onReceive（）方法的Context实例。

public void getRunning(Context context){ 
     ActivityManager am = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE); 
     List l = am.getRunningAppProcesses(); 
     Iterator i = l.iterator(); 
     PackageManager pm = context.getPackageManager(); 
     while(i.hasNext()) { 
      ActivityManager.RunningAppProcessInfo info = (ActivityManager.RunningAppProcessInfo)(i.next()); 
      try { 
      CharSequence c = pm.getApplicationLabel(pm.getApplicationInfo(info.processName, PackageManager.GET_META_DATA)); 
      Log.w("LABEL", c.toString()); 
      runningApplications.add(c.toString()); 
      }catch(Exception e) { 
      //Name Not Found Exception 
      } 
     } 

    } 

Answer 2

尝试为：

public class ScreenReceiver extends BroadcastReceiver { 
private Context ctext; 
    @Override 
    public void onReceive(Context context, Intent intent) { 
     ctext=context; 
     //OR you can also pass context as param to getRunning() 
     //your code here.... 
    } 
public void getRunning(){ 
     ActivityManager am = (ActivityManager)ctext.getSystemService(Context.ACTIVITY_SERVICE); 
     List l = am.getRunningAppProcesses(); 
     Iterator i = l.iterator(); 
     PackageManager pm = ctext.getPackageManager(); 
     while(i.hasNext()) { 
      ActivityManager.RunningAppProcessInfo info = (ActivityManager.RunningAppProcessInfo)(i.next()); 
      try { 
      CharSequence c = pm.getApplicationLabel(pm.getApplicationInfo(info.processName, PackageManager.GET_META_DATA)); 
      Log.w("LABEL", c.toString()); 
      runningApplications.add(c.toString()); 
      }catch(Exception e) { 
      //Name Not Found Exception 
      } 
     } 

    } 

}