isApplicationBroughtToBackground security feature misbehaves often

Question

I am using this to implement a security feature that displays a locking screen if my app regains the focus after coming back from a different app.

Now, the problem is that the security feature is sometimes shown twice. After digging around a bit I noticed that the topActivity from ActivityManager.getRunningTasks(1) is sometimes still the activity you just returned from.

In my case, the offending lingering apps are com.android.mms and com.google.android.apps.maps.

I have a calling facility as well within the application but it is not misbehaving.

I am completely baffled with this behavior.

Answer 1

This is really a problematic case with Android. Try the following which worked for me:

Have a base class for your activities. In it:

@Override
protected void onPause() {
    Utils.wentInBackground(this);
    super.onPause();
}

@Override
protected void onResume() {
    Utils.wentInForeground(this);
    super.onResume();
}

Then in a static utilities class have this:

public static void wentInBackground(final Activity which) {
    inBackground = true;
    lastPaused = which.getClass().getSimpleName();

    final PowerManager powerManager = (PowerManager) which.getSystemService(POWER_SERVICE);
    final boolean isScreenOn = powerManager.isScreenOn();

    if (isApplicationSentToBackground(which) || !isScreenOn) {
        // Do your security lockdown here.
    }
}


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;
}


public static void wentInForeground(final Activity which) {
    inBackground = false;
    final String activityName = which.getClass().getSimpleName();

    if (lastPaused.equals(activityName) || !isLoggedIn()) {

        if (isLoggedIn()) {
             // Do your security lockdown here again, if necessary.
        }

        // Show your security screen or whatever you need to.
    }
}

public static boolean isLoggedIn() {
    return loggedIn;
}