App block application does not block the apps intended even with using corrrect permissions, and api levels

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Java

Mobile

Android

API

I made a small app-block program segment and though it does not effect the rest of the code or the program it does not seem to trigger its actions when a user eneters another app, my emulator device is running API(18) and thus should not be effected by the recent API changes.

Code:

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
    List < ActivityManager.RunningTaskInfo > tasks = activityManager.getRunningTasks(Integer.MAX_VALUE);


    ActivityManager.RunningTaskInfo ar = tasks.get(0);
    String activityOnTop = ar.topActivity.getClassName();
    Intent lockIntent = new Intent(this, LockScreen.class);
    lockIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    ComponentName componentInfo = tasks.get(0).topActivity;
    if (!componentInfo.getPackageName().equals("com.example.epiclapser.noprocrastinate")) {
        this.startActivity(lockIntent);
    }

    setContentView(R.layout.activity_main_activity2);
}

Any help would be greatly appreciated.