從Android的廣播接收器中查找跑步活動

Question

我想從廣播接收器中查找當前正在運行的其他活動。 這是我從活動中使用的代碼，用於查找其他正在運行的活動，但是當我嘗試在廣播接收器中使用此代碼時，在以下幾行中會出錯：

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

顯示日食中的錯誤ACTIVITY_SERVICE無法解析為變量

 PackageManager pm = this.getPackageManager();

這顯示了eclipse中的錯誤。對於類型ScreenReceiver（我的廣播接收器），未定義方法getPackageManager（）

這是完整的代碼：

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

由於BroadcastReceiver不會從Context下降，因此您無法像在Activity中那樣使用this 。 您應該使用傳遞給onReceive（）方法的Context實例。

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

嘗試為：

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
          }
        }

    }

}