KeyguardManager fails to unlock kitkat screen

Question

I've noticed very interesting behavior of Android that I cannot explain. I'm using the following code to wake up the phone and disable keyguard:

        PowerManager.WakeLock mFullWakelock = mPowerManager.newWakeLock(
                (PowerManager.SCREEN_BRIGHT_WAKE_LOCK |
                        PowerManager.FULL_WAKE_LOCK |
                        PowerManager.ACQUIRE_CAUSES_WAKEUP),
                LOCK_TAG
        );

        mFullWakelock.acquire();

        KeyguardManager keyguardManager = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
        KeyguardManager.KeyguardLock keyguardLock = keyguardManager.newKeyguardLock(LOCK_TAG);

        keyguardLock.disableKeyguard();

Imagine there is cycle of wake (programmatically)->disable keyguard (programmatically)->press power button (manually)->wake->disable keyguard. The cycle works great until I manually press Home button while the phone's keyguard is disabled. After that, phone does wake up but keyguard is no longer disabled programmatically. I'd appreciate any ideas!

Please take a look at this: http://stackoverflow.com/a/14519861/4098821 — Robbe, Nov 12 '14 at 23:14
Robbe, please post this as answer and I'll accept it. Thanks! — NeviQ-OR, Nov 13 '14 at 09:16

score 0 · Accepted Answer · edited May 23 '17 at 12:16

0

The problem is that a keylock seems to expire whenever the user presses home button or opens a notification. So whenever this happens, you have to create a new keylock.

I used this solution and it worked great: https://stackoverflow.com/a/14519861/4098821

edited May 23 '17 at 12:16

Community

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answered Nov 13 '14 at 11:28

Robbe

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score 0 · Answer 2 · edited May 04 '16 at 13:41

I had the same problem and i solved it using reflection and making my application as system signed app.

Here's the code:

try{
                                   Class lockPatternUtilsCls = Class.forName("com.android.internal.widget.LockPatternUtils");
                                   Constructor lockPatternUtilsConstructor = 
                                       lockPatternUtilsCls.getConstructor(new Class[]{Context.class});
                                   lockPatternUtilsConstructor.setAccessible(true);
                                   Object lockPatternUtils = lockPatternUtilsConstructor.newInstance(ChangeDeviceLockMode.this);
                                   Method clearLockMethod = lockPatternUtils.getClass().getMethod("clearLock", boolean.class);
                                   clearLockMethod.setAccessible(true);
                                   Method setLockScreenDisabledMethod = lockPatternUtils.getClass().getMethod("setLockScreenDisabled", boolean.class);
                                   setLockScreenDisabledMethod.setAccessible(true);
                                   clearLockMethod.invoke(lockPatternUtils, false);
                                   setLockScreenDisabledMethod.invoke(lockPatternUtils, true);     
                                   Toast.makeText(ChangeDeviceLockMode.this,"none", Toast.LENGTH_LONG).show();  
                           }catch(Exception e){
                               System.err.println("An InvocationTargetException was caught!");
                                                   Throwable cause = e.getCause();
                                                   Toast.makeText(ChangeDeviceLockMode.this,"none--"+cause, Toast.LENGTH_LONG).show();  
                               Toast.makeText(ChangeDeviceLockMode.this,"none--"+e, Toast.LENGTH_LONG).show();  
                           }

You also need to add a permission in manifest

android:name="android.permission.ACCESS_KEYGUARD_SECURE_STORAGE" />

This permission requires app to be system signed.

make sure your application is system signed else the above code wont work — tanmeet, May 04 '16 at 12:42
How can I get a system signature? I'm developing a lock screen application, but the android shows a black screen if I let the keyguard unlocked after pressing the app preview button. Have you experienced this problem? — Pethő Jonatán, May 12 '16 at 20:09

KeyguardManager fails to unlock kitkat screen

2 Answers2

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