Android - how to completely disable keyguard

Question

I want to control enabling/disabling keyguard on the device. To do that I'm using DevicePolicyManager and KeyguardLock API of Android SDK.

Below is my implementation to manage this:

public class DeviceLocker {

private static DeviceLocker instance;

public static synchronized DeviceLocker getInstance(Context context) {
    if(instance==null) {
        instance = new DeviceLocker(context);
    }
    return instance;
}

private Context context;
private KeyguardLock lock;

private DeviceLocker(Context context) {
    this.context = context;
}

public void lock() {
    lock(true);
}

public void lock(boolean lockNow) {
    getLock().reenableKeyguard();
    DevicePolicyManager devicePolicyManager = getDevicePolicyManager();
    if(devicePolicyManager==null) {
        return;
    }
    LocalStorage storage = LocalStorage.from(context);
    
    boolean result = devicePolicyManager.resetPassword(storage.getPassword(),
            DevicePolicyManager.RESET_PASSWORD_REQUIRE_ENTRY);
    
    if(lockNow) {
        devicePolicyManager.lockNow();
    }
    storage.setDeviceLocked(true);
}

public void unlock() {
    DevicePolicyManager devicePolicyManager = getDevicePolicyManager();
    if(devicePolicyManager==null) {
        return;
    }
    devicePolicyManager.resetPassword("",0);
    getLock().disableKeyguard();
    LocalStorage.from(context).setDeviceLocked(false);
}

private KeyguardLock getLock() {
    if(lock==null){
        KeyguardManager kgManager = (KeyguardManager)context.getSystemService(Activity.KEYGUARD_SERVICE);
        lock = kgManager.newKeyguardLock(Context.KEYGUARD_SERVICE);
    }
    return lock;
}

private DevicePolicyManager getDevicePolicyManager() {
    DevicePolicyManager devicePolicyManager =
        (DevicePolicyManager)context.getSystemService(Context.DEVICE_POLICY_SERVICE);
    ComponentName deviceAdmin = new ComponentName(context, WatchGuardDeviceAdminReceiver.class);
    LocalStorage storage = LocalStorage.from(context);
    if(!devicePolicyManager.isAdminActive(deviceAdmin)) {
        return null;
    }
    if(!storage.isPasswordSet()) {
        UIUtils.showMessage(context, R.string.password_not_set);
        return null;
    }
    devicePolicyManager.setPasswordQuality(deviceAdmin,DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED);
    
    return devicePolicyManager;
}

}

It works ok regarding the lock of the screen, but unlock functionality works with some issues: sometimes it works as I want(completely removes any type of keyguard screen), but sometimes it shows a "Unlock with slide" keyguard screen.

Do you know what is the problem here? How to make it work stable (at least in all cases either show "Unlock to slide" or completely remove keyguard)?

Thanks in advance for your help.

EDIT

Just want to point out that my solution works but the problem is that it works unstable (sometimes removes keyguard completely and sometimes shows "slide" keyguard). And also I use it not just to disable the keyguard while showing some activity but to control lock/unlock of a device in common, so I use this code in Service, therefore I can't call getWindow().addFlags(..) cause I don't have the Window to apply.

Just wondering maybe anyone dealt with this unstable behavior.

Answer 1

You need to add this code:

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED|WindowManager.LayoutParams.FLAG_FULLSCREEN|
                WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.lockscreen);

        startService(new Intent(this,LockService.class).setAction(Intent.ACTION_SCREEN_OFF));
    }

Create LockService with:

@Override
    public int onStartCommand(Intent intent, int flags, int startId)
    {

        if(intent == null || intent.getAction() == null)
            return START_NOT_STICKY;

        String action = intent.getAction();

        if(action.equals(ACTION_SCREEN_OFF))
        {
           KeyguardManager.KeyguardLock k1;
           KeyguardManager km =(KeyguardManager)getSystemService(KEYGUARD_SERVICE);
           k1= km.newKeyguardLock("IN");
           k1.disableKeyguard();  
        }

        return START_NOT_STICKY;
    }

Actually, I don't know why, but k1.disableKeyguard(); works only in Service.

Answer 2

AFAIK it's not universally possible, otherwise, this would be a major security breach.

On a non-rooted phone, the most you can do is dismiss a non-secure keyguard or show your app above the secure keyguard.

Here's a combo to do this:

getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
        | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);

On a rooted phone, you can attempt to remove the secure keyguard (although you may have to reboot the device before it actually goes away).

Here's a combo for that (haven't tried it myself, but I'm pretty sure several "unlock your phone" apps in Play Store use this trick)

Runtime.getRuntime().exec("sudo rm /data/system/gesture.key");

I recommend you try this one through adb first. Also, here's an XDA thread with some more info on this: http://forum.xda-developers.com/showthread.php?t=1800799