Android Lock Phone Programatically without Strong authentication to unlock again

Question

I am trying to create an app that, upon launching, will lock the phone. (It acts as an alternative of pressing the physical lock button on the phone instead).

I was able to achieve it with this code:

MainActivity.kt

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            LockmeTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    Greeting("Android")
                }
            }
        }

        val deviceManger =
            getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
        val compName = ComponentName(this, AdminReceiver::class.java)
        val active: Boolean = deviceManger.isAdminActive(compName)

        if (!active) {
            val intent = Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN)
            intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, compName)
            intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "You should enable the app!")
            startActivity(intent)
        }else{
            deviceManger.lockNow()
        }

    }
}

policies.xml

<?xml version="1.0" encoding="utf-8"?>

<device-admin>
<uses-policies>
    <force-lock />
</uses-policies>
</device-admin>

AndroidManifest.xml

<receiver
        android:name= ".AdminReceiver"
        android:description= "@string/app_name"
        android:label= "@string/app_name"
        android:exported="false"
        android:permission= "android.permission.BIND_DEVICE_ADMIN" >
        <meta-data
            android:name= "android.app.device_admin"
            android:resource= "@xml/policies" />
        <intent-filter>
            <action android:name= "android.app.action.DEVICE_ADMIN_ENABLED" />
        </intent-filter>
    </receiver>

The issue here is that, after locking the phone, when I try to unlock it, it says Device is locked by admin and it needs strong authentication such as Pin / Password to unlock. I want it to use the non-strong authentication that was setup on the phone such as fingerprint or face unlock.

Any idea how i can achieve this ?

No you cannot because you're using system service to lock the phone which directly related to OS of mobile. So, for opening it also requires OS intervention, So it is not possible to bypass authentication(if it is set in mobile),hope it helps — Syed Ibrahim, Feb 14 '23 at 06:22
@JosephSible-ReinstateMonica with root access it can be done, i know. But, that will be not the ideal solution to the problem. what you think? — Syed Ibrahim, Feb 14 '23 at 06:29
@SyedIbrahim If the only way to do it is with root, I think "here's how to do it with root" is better than "it can't be done", even though that's not ideal. — Joseph Sible-Reinstate Monica, Feb 14 '23 at 06:40
There's an app on play store called lock screen which does this. So I don't think this is impossible. After it locks the phone i can unlock it with fingerprint. How does it work with root @JosephSible-ReinstateMonica? — Mervin Hemaraju, Feb 14 '23 at 07:08
Can you link to the exact app? There's a lot with similar names. — Joseph Sible-Reinstate Monica, Feb 14 '23 at 07:19
This is the one `https://play.google.com/store/apps/details?id=com.olalab.lockscreen` — Mervin Hemaraju, Feb 14 '23 at 07:32
@SyedIbrahim i don't want to bypass authentication. I don't want it to use strong authentication to unlock. I want it to keep using the non strong authentication that was setup on the phone such as fingerprint unlock etc... — Mervin Hemaraju, Feb 14 '23 at 07:35

Don Peter · Answer 1 · 2023-02-16T06:18:11.587

0

Acording to Android documentation, you need either admin previlages or LOCK_DEVICE permission.

With admin previlages, as mentioned the unlock will have to be done using pattern or pin.

LOCK_DEVICE permission is not available for 3rd party apps.

Looks like there is an option to acheive this if you are building a kiosk app. I havent explored more on this.

Hope this helps.

edited Feb 16 '23 at 06:18

answered Feb 16 '23 at 06:11

Don Peter

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Android Lock Phone Programatically without Strong authentication to unlock again

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