协议：如何检查可能存在或不存在的响应中的字段(pact: how to check a a field in the response that may or may not exist)

 在我在我的问题中提到的应用程序中，没有覆盖默认行为。 这是我的错误，我采取了错误的方式。 使用Handler可以实现相同的功能。 在我的应用程序中，我使用了一个单击按钮启动的服务 。 在服务内部，我曾经使用过处理程序。 下面，我发布了代码片段。 
 
public class DialerService extends Service {
ActivityManager am;
List<RunningAppProcessInfo> mAppProcessInfosList;
private Runnable myRunnable;
boolean threadDone = true;
Handler mHandler;
boolean isLockedAppRunning = false;

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

public void onCreate() {
    am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
    mAppProcessInfosList = new ArrayList<ActivityManager.RunningAppProcessInfo>();
    mHandler = new Handler();
    Log.v("Dialer Service", "onCreate called");
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    myRunnable = new Runnable() {

        @Override
        public void run() {
            isRestrictedAppRunning();
        }
    };

    new Thread(new Runnable() {
        public void run() {
            while (threadDone) {

                try {
                    mHandler.post(myRunnable);
                } catch (Exception e) {

                }
            }
        }
    }).start();
    return START_STICKY;
}

private void isRestrictedAppRunning() {
    mAppProcessInfosList = am.getRunningAppProcesses();
    for (int i = 0; i < mAppProcessInfosList.size(); i++) {
        if (mAppProcessInfosList.get(i).processName
                .equals("com.android.phone")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.email")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.mms")) {
            isLockedAppRunning = true;
            Intent dialogIntent = new Intent(getBaseContext(),
                    TestActivity.class);
            dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            getApplication().startActivity(dialogIntent);
        }
    }
}

@Override
public void onDestroy() {
    super.onDestroy();
    this.threadDone = false;
}
}
 
 这段代码来自我的虚拟应用程序。 在实际的应用程序中有很多条件，仍然需要实现很多东西。 但是，我所需要的实际上将以这种方式工作。 

In the app that I mentioned in my question no default behavior was overridden. That was my mistake, I took it in wrong way. The same functionality can be achieved using Handler. In my app I used a service which starts on click of a button. Inside the service,, I had used handler. Below, I am posting the code snippet.
 
public class DialerService extends Service {
ActivityManager am;
List<RunningAppProcessInfo> mAppProcessInfosList;
private Runnable myRunnable;
boolean threadDone = true;
Handler mHandler;
boolean isLockedAppRunning = false;

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

public void onCreate() {
    am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
    mAppProcessInfosList = new ArrayList<ActivityManager.RunningAppProcessInfo>();
    mHandler = new Handler();
    Log.v("Dialer Service", "onCreate called");
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    myRunnable = new Runnable() {

        @Override
        public void run() {
            isRestrictedAppRunning();
        }
    };

    new Thread(new Runnable() {
        public void run() {
            while (threadDone) {

                try {
                    mHandler.post(myRunnable);
                } catch (Exception e) {

                }
            }
        }
    }).start();
    return START_STICKY;
}

private void isRestrictedAppRunning() {
    mAppProcessInfosList = am.getRunningAppProcesses();
    for (int i = 0; i < mAppProcessInfosList.size(); i++) {
        if (mAppProcessInfosList.get(i).processName
                .equals("com.android.phone")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.email")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.mms")) {
            isLockedAppRunning = true;
            Intent dialogIntent = new Intent(getBaseContext(),
                    TestActivity.class);
            dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            getApplication().startActivity(dialogIntent);
        }
    }
}

@Override
public void onDestroy() {
    super.onDestroy();
    this.threadDone = false;
}
}
 
This code is from my dummy app. There are lot more conditions in actual app and still lots of things need to implemented. But, what I needed actually will work in this way.