So basically I am trying to develop an App Lock application where the user can select which app they want to lock using Biometric stored in the device. I have already fetched the list of apps and store the package name in the shared preference once it is locked.

Now I want to create a foreground service to check when an app is launch is it present in my List of locked apps in the Shared Preference. For this I have created the Foreground service, but the problem is the BiometricPrompt only accepts Fragment/FragmentActivity as the 1st Parameter.

This is my ForegroundAppLockService.kt

class ForegroundAppLockService : Service() {

    private lateinit var biometricPrompt: BiometricPrompt

    private val notificationId = 12345
    private val channelId = "app_lock_channel"
    private val channelName = "App Lock Service"

    override fun onCreate() {
        super.onCreate()
        createNotificationChannel()
        biometricPrompt = createBiometricPrompt()
        startAppLaunchAccessibilityService()
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        startForeground(notificationId, createNotification())
        return START_STICKY
    }

    override fun onBind(intent: Intent?): IBinder? {
        return null
    }

    private fun createBiometricPrompt(): BiometricPrompt {
        val executor = ContextCompat.getMainExecutor(applicationContext)
        val callback = object : BiometricPrompt.AuthenticationCallback() {
            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                super.onAuthenticationSucceeded(result)
                Toast.makeText(applicationContext, "App unlocked!", Toast.LENGTH_SHORT).show()
            }
        }

        return BiometricPrompt(this, executor, callback)
    }

    private fun createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                channelId,
                channelName,
                NotificationManager.IMPORTANCE_DEFAULT
            )
            val notificationManager = getSystemService(NotificationManager::class.java)
            notificationManager.createNotificationChannel(channel)
        }
    }

    private fun createNotification(): Notification {
        val pendingIntent: PendingIntent =
            PendingIntent.getActivity(this, 0, Intent(), PendingIntent.FLAG_UPDATE_CURRENT)

        return NotificationCompat.Builder(this, channelId)
            .setContentTitle("App Lock Service")
            .setContentText("Monitoring app launches")
            .setSmallIcon(R.drawable.icon)
            .setContentIntent(pendingIntent)
            .build()
    }

    private fun startAppLaunchAccessibilityService() {
        val intent = Intent(this, AppLaunchAccessibilityService::class.java)
        startService(intent)
    }

    companion object {
        fun startService(context: Context) {
            val intent = Intent(context, ForegroundAppLockService::class.java)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                context.startForegroundService(intent)
            } else {
                context.startService(intent)
            }
        }

        fun startBiometricAuthentication(context: Context) {
            val serviceIntent = Intent(context, ForegroundAppLockService::class.java)
            ContextCompat.startForegroundService(context, serviceIntent)
        }

        fun stopService(context: Context) {
            val intent = Intent(context, ForegroundAppLockService::class.java)
            context.stopService(intent)
        }
    }
}

And this is the AppLaunchAccessibilityService.

class AppLaunchAccessibilityService : AccessibilityService() {

    private lateinit var sharedPreferences: SharedPreferences

    override fun onCreate() {
        super.onCreate()
        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
    }

    override fun onAccessibilityEvent(event: AccessibilityEvent?) {
        if (event?.eventType == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED) {
            val packageName = event.packageName?.toString()
            packageName?.let {
                if (isAppLocked(packageName)) {
                    showBiometricPrompt()
                }
            }
        }
    }

    override fun onInterrupt() {

    }

    private fun isAppLocked(packageName: String): Boolean {
        val lockedPackages = getLockedPackages()
        return lockedPackages.contains(packageName)
    }

    private fun getLockedPackages(): Set<String> {
        val lockedPackagesKey = "key_locked_packages"
        return sharedPreferences.getStringSet(lockedPackagesKey, HashSet()) ?: HashSet()
    }

    private fun showBiometricPrompt() {
        ForegroundAppLockService.startBiometricAuthentication(this)
    }
}

I want the Biometric prompt to be shown whenever user clicks on any app that is present in my lockedApps.