从Android的广播接收器中查找跑步活动

Question

我想从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的代码，用于查找其他正在运行的活动，但是当我尝试在广播接收器中使用此代码时，在以下几行中会出错：

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

显示日食中的错误ACTIVITY_SERVICE无法解析为变量

 PackageManager pm = this.getPackageManager();

这显示了eclipse中的错误。对于类型ScreenReceiver（我的广播接收器），未定义方法getPackageManager（）

这是完整的代码：

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BroadcastReceiver不会从Context下降，因此您无法像在Activity中那样使用this 。 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
          }
        }

    }

}