Use the current passcode length on unlock screen

Author: Radiokot

app/src/main/java/ua/com/radiokot/money/lock/AppLockModule.kt

@@ -62,6 +62,7 @@ val appLockModule = module {
 
     viewModel {
         SetUpPasscodeScreenViewModel(
+            passcodeLength = 4,
             enableAppLockUseCase = get(),
         )
     }

app/src/main/java/ua/com/radiokot/money/lock/logic/AppLock.kt

@@ -25,17 +25,37 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.flow.StateFlow
+import ua.com.radiokot.money.MoneyAppActivity
 import ua.com.radiokot.money.lazyLogger
 import ua.com.radiokot.money.lock.data.AppLockPreferences
 import ua.com.radiokot.money.map
 
+/**
+ * A lock for app screens.
+ * Locks if the passcode is set up and the app has been in background long enough.
+ * It is purely visual, no encryption/decryption is happening under the hood.
+ *
+ * @see MoneyAppActivity.requiresUnlocking
+ */
 class AppLock(
     private val preferences: AppLockPreferences,
 ) {
     private val log by lazyLogger("AppLock")
     private val coroutineScope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
     private var wentToBackgroundAtMs: Long = 0
 
+    /**
+     * If [isEnabled], length of the current passcode,
+     * 0 otherwise.
+     */
+    val currentPasscodeLength: Int
+        get() =
+            preferences
+                .appLockPasscode
+                .value
+                ?.length
+                ?: 0
+
     val isEnabled: StateFlow<Boolean> =
         preferences
             .appLockPasscode

app/src/main/java/ua/com/radiokot/money/lock/view/SetUpPasscodeScreenViewModel.kt

@@ -32,12 +32,12 @@ import ua.com.radiokot.money.lazyLogger
 import ua.com.radiokot.money.lock.logic.EnableAppLockUseCase
 
 class SetUpPasscodeScreenViewModel(
+    val passcodeLength: Int,
     private val enableAppLockUseCase: EnableAppLockUseCase,
 ) : ViewModel() {
 
     private val log by lazyLogger("SetUpPasscodeScreenVM")
 
-    val passcodeLength = 4
     private val _isRepeating: MutableStateFlow<Boolean> = MutableStateFlow(false)
     val isRepeating = _isRepeating.asStateFlow()
     private val _passcode: MutableStateFlow<String> = MutableStateFlow("")

app/src/main/java/ua/com/radiokot/money/lock/view/UnlockActivity.kt

@@ -100,10 +100,10 @@ class UnlockActivity : MoneyAppActivity(
     @Composable
     private fun Content() {
 
-        val passcode = rememberSaveable {
+        val enteredPasscode = rememberSaveable {
             mutableStateOf("")
         }
-        val length = 4
+        val length = lock.currentPasscodeLength
 
         BoxWithConstraints(
             contentAlignment = Alignment.Center,
@@ -140,17 +140,17 @@ class UnlockActivity : MoneyAppActivity(
 
                 PasscodeInput(
                     length = length,
-                    passcode = passcode,
+                    passcode = enteredPasscode,
                     onPasscodeChanged = { newValue: String ->
 
-                        passcode.value = newValue
+                        enteredPasscode.value = newValue
 
                         if (newValue.length == length) {
                             if (lock.unlock(newValue)) {
                                 setResult(RESULT_OK)
                                 finish()
                             } else {
-                                passcode.value = ""
+                                enteredPasscode.value = ""
 
                                 Toast
                                     .makeText(
@@ -163,7 +163,7 @@ class UnlockActivity : MoneyAppActivity(
                         }
                     },
                     onBackspaceClicked = {
-                        passcode.value = passcode.value.dropLast(1)
+                        enteredPasscode.value = enteredPasscode.value.dropLast(1)
                     },
                     isBiometricsButtonShown = canUseBiometrics,
                     onBiometricsClicked = ::showBiometricsPrompt,

fastlane/metadata/android/en-US/changelogs/35.txt

@@ -0,0 +1,2 @@
+Added:
+- Ability to lock the app with a passcode