Add opt-in device credential app lock

app/src/main/java/se/ajpanton/notificationlog/MainActivity.kt

@@ -1,6 +1,9 @@
 package se.ajpanton.notificationlog
 
 import android.os.Bundle
+import android.hardware.biometrics.BiometricPrompt
+import android.hardware.biometrics.BiometricManager.Authenticators
+import android.os.CancellationSignal
 import android.content.res.Configuration
 import android.view.Menu
 import android.view.MenuItem
@@ -19,11 +22,13 @@ import androidx.fragment.app.commit
 import com.google.android.material.navigation.NavigationView
 import se.ajpanton.notificationlog.databinding.ActivityMainBinding
 import se.ajpanton.notificationlog.settings.LoggingType
+import se.ajpanton.notificationlog.settings.AppLockStore
 
 class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
     private lateinit var binding: ActivityMainBinding
     private lateinit var drawerToggle: ActionBarDrawerToggle
     private var permanentSidebar = false
+    private var needsUnlock = true
     private var currentItemId = R.id.nav_view_logs
     private var drawerNavigationBasePaddingLeft: Int? = null
     private var permanentNavigationBasePaddingLeft: Int? = null
@@ -77,6 +82,27 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
         super.onSaveInstanceState(outState)
     }
 
+    override fun onResume() {
+        super.onResume()
+        if (needsUnlock && AppLockStore(this).enabled) requestUnlock()
+    }
+
+    override fun onStop() {
+        super.onStop()
+        if (!isChangingConfigurations) needsUnlock = true
+    }
+
+    private fun requestUnlock() {
+        BiometricPrompt.Builder(this)
+            .setTitle("Unlock Notification Log")
+            .setAllowedAuthenticators(Authenticators.BIOMETRIC_STRONG or Authenticators.DEVICE_CREDENTIAL)
+            .build()
+            .authenticate(CancellationSignal(), mainExecutor, object : BiometricPrompt.AuthenticationCallback() {
+                override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult?) { needsUnlock = false }
+                override fun onAuthenticationError(errorCode: Int, errString: CharSequence?) { finishAndRemoveTask() }
+            })
+    }
+
     override fun onNavigationItemSelected(item: MenuItem): Boolean {
         if (item.itemId == R.id.nav_settings_header) {
             return false