Problems With Android Lock In Custom Lock Screen App

I built a custom lock screen app that uses a broadcast receiver and service to listen for when the user turns on or off the screen and from there launch my activity. The activity i

Solution 1:

The behavior of keyguard-related logic can vary from device to device. That's because lockscreens are often custom-made by device manufacturers (i.e. not stock), some of them respect the keyguard logic you use, some don't.

Also, afaik the newer way to control keyguard is to use window flags:

// inside activitygetWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
        | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);

This will not solve the problem though, devices still have their say about this.

E.g. from my experience, Galaxy Nexus will show your activity's window above keyguard but will not dismiss it (you'd think Google-branded device should respect the flag, eh), so if you hit the back button in your activity - you'll get standard lockscreen --- while HTC One X seems to handle the dismiss part properly: your activity window will cause standard lockscreen to get dismissed as expected.

I found no way to force all devices to behave properly. Android API is not meant to enable you to create custom lock screens (at least not currently). Take a look at the ones in the store - they all have the exact same problem of not being stable enough.

As Dianne Hackborn says in this Google Groups answer, anything you can do in this regard is a hack so expect it to break from time to time.

Solution 2:

I tried to compile your code and got the same error you were talking about. I tried to modify it to make it to work and finally got the problem!!!

publicclassScreenReceiverextendsBroadcastReceiver {

    publicstatic ArrayList<String> runningApplications = new ArrayList<String>();
    private Context ctext;
    publicstatic boolean screenIsLocked;
    publicstatic KeyguardManager keyguardManager;
    publicstatic KeyguardLock lock;

    @Override
    publicvoidonReceive(final Context context, final Intent intent) {
        ctext = context;
        keyguardManager = (KeyguardManager)ctext.getSystemService(Activity.KEYGUARD_SERVICE);
        lock = keyguardManager.newKeyguardLock(Context.KEYGUARD_SERVICE);
        lock.disableKeyguard();


        if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
            screenIsLocked = true;
            Log.d("ScreenReceiver", "False");

            Intent intenti = new Intent();
            intenti.setClass(context, starterActivity.class);
            intenti.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            intenti.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(intenti);


        } elseif (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
            screenIsLocked = false;
            Log.d("ScreenReceiver", "True");

                        Intent intenti = new Intent();
                        intenti.setClass(context, starterActivity.class);
                        intenti.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                        intenti.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                        context.startActivity(intenti);
        }
    }

With this change to the broadcast receiver class I was able to overcome the problem

Try it and tell me if there is any problem.

EDIT:I think the problem might lie in the finish() method....Android dumps apps when it requires memory...I think finish() might be helping android in trashing the app(and this might be the reason why your problem occurs randomly)