如何檢查應用程序是否在BroadcastReceiver中的前台后台運行

Question

我想檢查我的應用程序是在后台還是在Foreground中，我還想要打開或不使用BroadcastReceiver檢查應用程序

public class CheckRunningApplicationReceiver extends BroadcastReceiver {
Context mContext;

public int mId = 1000;
NotificationManager mNotificationManager;

@Override
public void onReceive(Context aContext, Intent anIntent) {
    mContext = aContext;
    Boolean isAppOpen = isApplicationSentToBackground(aContext);
    mNotificationManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
    if (isAppOpen) {
        //openNotification();
    } else {
        //mNotificationManager.cancel(mId);
    }

}

private void openNotification() {// Instantiate notification with icon and
                                    // ticker message
    Notification notification = new Notification(R.drawable.ic_launcher,"Notification message!", System.currentTimeMillis());
    PendingIntent i = PendingIntent.getActivity(mContext, 0, new Intent(mContext,MainActivity.class), 0);
    notification.setLatestEventInfo(mContext, "Notification Created","Click here to see the message", i);
    notification.flags = Notification.FLAG_ONGOING_EVENT; 
    mNotificationManager.notify(mId, notification);
}

public static boolean isApplicationSentToBackground(final Context context) {
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<RunningTaskInfo> tasks = am.getRunningTasks(1);
    if (!tasks.isEmpty()) {
        ComponentName topActivity = tasks.get(0).topActivity;
        if (!topActivity.getPackageName().equals(context.getPackageName())) {
            return true;
        }
    }

    return false;
}

}

對此有什么解決方案，幫助我，謝謝。

Answer 1

即使應用程序處於后台，BroadcastReceiver也能正常工作，因為接收方接收的事件是全局發送的，並且每個應用程序都已注冊以監聽這些應用程序，無論應用程序是否正在運行。

要處理此問題，請在BroadcastReceiver的onReceive代碼中檢查您的應用是否位於前台。

我知道有一個 - 也是唯一一個 - 持續有效的方法來做到這一點。 您需要跟蹤應用程序的暫停/恢復操作。 確保在每項活動中檢查此項。

這個答案中有一些示例代碼。 在您的情況下，您需要在從BroadcastReceiver執行任何操作之前檢查MyApplication.isActivityVisible（）== true作為驗證。

Answer 2

在您的活動注冊廣播接收器中檢查活動是在前台還是后台。

StackAnswer.java
public class StackAnswer extends Activity {
    public static final int IS_ALIVE = Activity.RESULT_FIRST_USER;
    public static final String CHECK_ALIVE_ACTION = "CHECK_ALIVE_ACTION";
    private BroadcastReceiver mRefreshReceiver;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRefreshReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {

                Log.i("onReceive","BroadcastIntent received in MainActivity");

                // TODO:                
                // Check to make sure this is an ordered broadcast
                // Let sender know that the Intent was received
                // by setting result code to MainActivity.IS_ALIVE
                setResultCode(MainActivity.IS_ALIVE);
            }
        };
    }



    // Register the BroadcastReceiver
    @Override
    protected void onResume() {
        super.onResume();

        // TODO:
        // Register the BroadcastReceiver to receive a 
        // DATA_REFRESHED_ACTION broadcast
        IntentFilter filter = new IntentFilter();
        filter.addAction(CHECK_ALIVE_ACTION);         
        registerReceiver(mRefreshReceiver, filter);     

    }

    @Override
    protected void onPause() {

        // TODO:
        // Unregister the BroadcastReceiver if it has been registered
        // Note: To work around a Robotium issue - check that the BroadcastReceiver
        // is not null before you try to unregister it
        if(mRefreshReceiver!=null){
            unregisterReceiver(mRefreshReceiver);
        }
        super.onPause();
    }


}

從背景發送廣播以檢查天氣活動是否存在

   BackgroundTask.java
   public class BackgroundTask {

    private void checkIfForeground (Context mApplicationContext){
        mApplicationContext.sendOrderedBroadcast(new Intent(
                StackAnswer.CHECK_ALIVE_ACTION), null,
                new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                // TODO: Check whether the result code is not MainActivity.IS_ALIVE
                if (getResultCode() != StackAnswer.IS_ALIVE) {
                    //Background 
                }else{
                    //Foreground 
                }
            }
        }, null, 0, null, null);
    }
}