New SettingsScreen with export dir preference

app/build.gradle.kts

@@ -116,6 +116,7 @@ dependencies {
     implementation(libs.androidx.camera.lifecycle)
     implementation(libs.androidx.camera.view)
     implementation(libs.androidx.datastore)
+    implementation(libs.androidx.datastore.preferences)
     implementation(libs.protobuf.javalite)
     implementation(libs.litert)
     implementation(libs.litert.support)

app/src/main/java/org/fairscan/app/FairScanApp.kt

@@ -32,6 +32,8 @@ import org.fairscan.app.ui.screens.about.AboutViewModel
 import org.fairscan.app.ui.screens.camera.CameraViewModel
 import org.fairscan.app.ui.screens.export.ExportViewModel
 import org.fairscan.app.ui.screens.home.HomeViewModel
+import org.fairscan.app.ui.screens.settings.SettingsRepository
+import org.fairscan.app.ui.screens.settings.SettingsViewModel
 import java.io.File
 
 class FairScanApp : Application() {
@@ -58,6 +60,7 @@ class AppContainer(context: Context) {
     val logger = FileLogger(logRepository)
     val imageSegmentationService = ImageSegmentationService(context, logger)
     val recentDocumentsDataStore = context.recentDocumentsDataStore
+    val settingsRepository = SettingsRepository(context)
 
     @Suppress("UNCHECKED_CAST")
     inline fun <reified VM : ViewModel> viewModelFactory(
@@ -73,4 +76,5 @@ class AppContainer(context: Context) {
     val cameraViewModelFactory = viewModelFactory { CameraViewModel(it) }
     val exportViewModelFactory = viewModelFactory { ExportViewModel(it) }
     val aboutViewModelFactory = viewModelFactory { AboutViewModel(it) }
+    val settingsViewModelFactory = viewModelFactory { SettingsViewModel(it) }
 }

app/src/main/java/org/fairscan/app/MainActivity.kt

@@ -67,6 +67,8 @@ import org.fairscan.app.ui.screens.export.ExportViewModel
 import org.fairscan.app.ui.screens.export.PdfGenerationActions
 import org.fairscan.app.ui.screens.home.HomeScreen
 import org.fairscan.app.ui.screens.home.HomeViewModel
+import org.fairscan.app.ui.screens.settings.SettingsScreen
+import org.fairscan.app.ui.screens.settings.SettingsViewModel
 import org.fairscan.app.ui.theme.FairScanTheme
 import org.opencv.android.OpenCVLoader
 
@@ -83,6 +85,8 @@ class MainActivity : ComponentActivity() {
         val cameraViewModel: CameraViewModel by viewModels { appContainer.cameraViewModelFactory }
         val exportViewModel: ExportViewModel by viewModels { appContainer.exportViewModelFactory }
         val aboutViewModel: AboutViewModel by viewModels { appContainer.aboutViewModelFactory }
+        val settingsViewModel: SettingsViewModel
+            by viewModels { appContainer.settingsViewModelFactory }
         lifecycleScope.launch(Dispatchers.IO) {
             exportViewModel.cleanUpOldPdfs(1000 * 3600)
         }
@@ -158,11 +162,35 @@ class MainActivity : ComponentActivity() {
                     is Screen.Overlay.Libraries -> {
                         LibrariesScreen(onBack = navigation.back)
                     }
+                    is Screen.Overlay.Settings -> {
+                        SettingsScreenWrapper(settingsViewModel, navigation)
+                    }
                 }
             }
         }
     }
 
+    @Composable
+    private fun SettingsScreenWrapper(settingsViewModel: SettingsViewModel, nav: Navigation) {
+        val launcher = rememberLauncherForActivityResult(
+            contract = ActivityResultContracts.OpenDocumentTree()
+        ) { uri ->
+            if (uri != null) {
+                val flags = Intent.FLAG_GRANT_READ_URI_PERMISSION or
+                        Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+                contentResolver.takePersistableUriPermission(uri, flags)
+                settingsViewModel.setExportDirUri(uri.toString())
+            }
+        }
+        val settingsUiState by settingsViewModel.uiState.collectAsStateWithLifecycle()
+        SettingsScreen(
+            settingsUiState,
+            onChooseDirectoryClick = { launcher.launch(null) },
+            onResetExportDirClick = { settingsViewModel.setExportDirUri(null) },
+            onBack = nav.back
+        )
+    }
+
     @Composable
     private fun CollectAboutEvents(
         context: Context,
@@ -303,5 +331,6 @@ private fun navigation(viewModel: MainViewModel): Navigation = Navigation(
     toExportScreen = { viewModel.navigateTo(Screen.Main.Export) },
     toAboutScreen = { viewModel.navigateTo(Screen.Overlay.About) },
     toLibrariesScreen = { viewModel.navigateTo(Screen.Overlay.Libraries) },
+    toSettingsScreen = { viewModel.navigateTo(Screen.Overlay.Settings) },
     back = { viewModel.navigateBack() }
 )

app/src/main/java/org/fairscan/app/ui/Navigation.kt

@@ -24,6 +24,7 @@ sealed class Screen {
     sealed class Overlay : Screen() {
         object About : Overlay()
         object Libraries : Overlay()
+        object Settings : Overlay()
     }
 }
 
@@ -34,6 +35,7 @@ data class Navigation(
     val toExportScreen: () -> Unit,
     val toAboutScreen: () -> Unit,
     val toLibrariesScreen: () -> Unit,
+    val toSettingsScreen: () -> Unit,
     val back: () -> Unit,
 )
 

app/src/main/java/org/fairscan/app/ui/PreviewUtils.kt

@@ -21,7 +21,7 @@ import kotlinx.collections.immutable.persistentListOf
 import org.fairscan.app.ui.state.DocumentUiModel
 
 fun dummyNavigation(): Navigation {
-    return Navigation({}, {}, {}, {}, {}, {}, {})
+    return Navigation({}, {}, {}, {}, {}, {}, {}, {})
 }
 
 fun fakeDocument(): DocumentUiModel {

app/src/main/java/org/fairscan/app/ui/components/Buttons.kt

@@ -19,7 +19,6 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
-import androidx.compose.material.icons.filled.Info
 import androidx.compose.material3.Button
 import androidx.compose.material3.FilledIconButton
 import androidx.compose.material3.Icon
@@ -85,19 +84,3 @@ fun BackButton(onClick: () -> Unit, modifier: Modifier = Modifier) {
         )
     }
 }
-
-@Composable
-fun AboutScreenNavButton(
-    onClick: () -> Unit,
-    modifier: Modifier = Modifier
-) {
-    IconButton(
-        onClick = onClick,
-        modifier = modifier
-    ) {
-        Icon(
-            imageVector = Icons.Default.Info,
-            contentDescription = stringResource(R.string.about),
-            tint = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.6f))
-    }
-}

app/src/main/java/org/fairscan/app/ui/components/Scaffold.kt

@@ -26,18 +26,32 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.safeDrawing
 import androidx.compose.foundation.layout.windowInsetsPadding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Settings
 import androidx.compose.material3.BottomAppBar
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.unit.dp
+import org.fairscan.app.ui.Navigation
 
 @Composable
 fun MyScaffold(
-    toAboutScreen: () -> Unit,
+    navigation: Navigation,
     pageListState: CommonPageListState,
     pageListButton: (@Composable () -> Unit)? = null,
     bottomBar: @Composable () -> Unit,
@@ -69,8 +83,8 @@ fun MyScaffold(
                     .windowInsetsPadding(WindowInsets.safeDrawing)
             )
         }
-        AboutScreenNavButton(
+        AppOverflowMenu(
-            onClick = toAboutScreen,
+            navigation,
             modifier = Modifier
                 .align(Alignment.TopEnd)
                 .windowInsetsPadding(WindowInsets.safeDrawing)
@@ -86,11 +100,11 @@ fun DocumentBar(
     pageListButton: (@Composable () -> Unit)? = null,
 ) {
     val isLandscape = isLandscape(LocalConfiguration.current)
-    Column (
+    Column(
         horizontalAlignment = Alignment.CenterHorizontally,
         modifier = modifier.background(MaterialTheme.colorScheme.surfaceContainer)
     ) {
-        Box (
+        Box(
             if (isLandscape)
                 Modifier
                     .weight(1f)
@@ -144,3 +158,45 @@ fun DocumentBar(
 fun isLandscape(configuration: Configuration): Boolean {
     return configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
 }
+
+@Composable
+fun AppOverflowMenu(
+    navigation: Navigation,
+    modifier: Modifier = Modifier,
+) {
+    var expanded by remember { mutableStateOf(false) }
+    Box(
+        modifier
+    ) {
+        IconButton(onClick = { expanded = true }) {
+            Icon(Icons.Default.MoreVert, contentDescription = "Menu")
+        }
+
+        DropdownMenu(
+            expanded = expanded,
+            onDismissRequest = { expanded = false },
+            modifier = Modifier
+                .background(MaterialTheme.colorScheme.surface)
+        ) {
+
+            DropdownMenuItem(
+                leadingIcon = { Icon(Icons.Default.Settings, contentDescription = null) },
+                text = { Text("Settings") },
+                onClick = {
+                    expanded = false
+                    navigation.toSettingsScreen()
+                }
+            )
+
+            DropdownMenuItem(
+                leadingIcon = { Icon(Icons.Default.Info, contentDescription = null) },
+                text = { Text("About") },
+                onClick = {
+                    expanded = false
+                    navigation.toAboutScreen()
+                }
+            )
+        }
+    }
+}
+

app/src/main/java/org/fairscan/app/ui/screens/DocumentScreen.kt

@@ -95,7 +95,7 @@ fun DocumentScreen(
     }
 
     MyScaffold(
-        toAboutScreen = navigation.toAboutScreen,
+        navigation = navigation,
         pageListState = CommonPageListState(
             document,
             onPageClick = { index -> currentPageIndex.intValue = index },
@@ -103,7 +103,6 @@ fun DocumentScreen(
             currentPageIndex = currentPageIndex.intValue,
             listState = listState,
         ),
-        onBack = navigation.back,
         bottomBar = {
             BottomBar(navigation)
         },

app/src/main/java/org/fairscan/app/ui/screens/camera/CameraScreen.kt

@@ -221,9 +221,8 @@ private fun CameraScreenScaffold(
 
     Box {
         MyScaffold(
-            toAboutScreen = navigation.toAboutScreen,
+            navigation = navigation,
             pageListState = pageListState,
-            onBack = navigation.back,
             bottomBar = { Bar(cameraUiState.pageCount, onFinalizePressed) }
         ) { modifier ->
             CameraPreviewBox(

app/src/main/java/org/fairscan/app/ui/screens/export/ExportScreen.kt

@@ -69,7 +69,7 @@ import androidx.core.net.toUri
 import org.fairscan.app.R
 import org.fairscan.app.data.GeneratedPdf
 import org.fairscan.app.ui.Navigation
-import org.fairscan.app.ui.components.AboutScreenNavButton
+import org.fairscan.app.ui.components.AppOverflowMenu
 import org.fairscan.app.ui.components.BackButton
 import org.fairscan.app.ui.components.MainActionButton
 import org.fairscan.app.ui.components.NewDocumentDialog
@@ -154,7 +154,7 @@ fun ExportScreen(
                 title = { Text(stringResource(R.string.export_pdf)) },
                 navigationIcon = { BackButton(navigation.back) },
                 actions = {
-                    AboutScreenNavButton(onClick = navigation.toAboutScreen)
+                    AppOverflowMenu(navigation)
                 }
             )
         }

app/src/main/java/org/fairscan/app/ui/screens/home/HomeScreen.kt

@@ -55,13 +55,13 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import kotlinx.collections.immutable.persistentListOf
-import org.fairscan.app.ui.components.CameraPermissionState
-import org.fairscan.app.ui.Navigation
 import org.fairscan.app.R
-import org.fairscan.app.ui.components.rememberCameraPermissionState
+import org.fairscan.app.ui.Navigation
-import org.fairscan.app.ui.components.AboutScreenNavButton
+import org.fairscan.app.ui.components.AppOverflowMenu
+import org.fairscan.app.ui.components.CameraPermissionState
 import org.fairscan.app.ui.components.formatDate
 import org.fairscan.app.ui.components.pageCountText
+import org.fairscan.app.ui.components.rememberCameraPermissionState
 import org.fairscan.app.ui.dummyNavigation
 import org.fairscan.app.ui.fakeDocument
 import org.fairscan.app.ui.state.DocumentUiModel
@@ -82,9 +82,7 @@ fun HomeScreen(
         topBar = {
             TopAppBar(
                 title = { Text(stringResource(R.string.app_name)) },
-                actions = {
+                actions = { AppOverflowMenu(navigation) }
-                    AboutScreenNavButton(onClick = navigation.toAboutScreen)
-                }
             )
         },
     ) { padding ->

app/src/main/java/org/fairscan/app/ui/screens/settings/SettingsRepository.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.app.ui.screens.settings
+
+import android.content.Context
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import androidx.datastore.preferences.preferencesDataStore
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+
+private val Context.dataStore by preferencesDataStore(name = "fairscan_settings")
+
+class SettingsRepository(private val context: Context) {
+
+    private val EXPORT_DIR_URI = stringPreferencesKey("export_dir_uri")
+
+    val exportDirUri: Flow<String?> =
+        context.dataStore.data.map { prefs ->
+            prefs[EXPORT_DIR_URI]
+        }
+
+    suspend fun setExportDirUri(uri: String?) {
+        context.dataStore.edit { prefs ->
+            if (uri == null) {
+                prefs.remove(EXPORT_DIR_URI)
+            } else {
+                prefs[EXPORT_DIR_URI] = uri
+            }
+        }
+    }
+}

app/src/main/java/org/fairscan/app/ui/screens/settings/SettingsScreen.kt

@@ -0,0 +1,173 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.app.ui.screens.settings
+
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Folder
+import androidx.compose.material3.Card
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.core.net.toUri
+import org.fairscan.app.ui.components.BackButton
+import org.fairscan.app.ui.theme.FairScanTheme
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun SettingsScreen(
+    uiState: SettingsUiState,
+    onChooseDirectoryClick: () -> Unit,
+    onResetExportDirClick: () -> Unit,
+    onBack: () -> Unit,
+) {
+    BackHandler { onBack() }
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = { Text("Settings") },
+                navigationIcon = { BackButton(onBack) },
+            )
+        }
+    ) { paddingValues ->
+        SettingsContent(uiState, onChooseDirectoryClick, onResetExportDirClick, modifier = Modifier.padding(paddingValues))
+    }
+
+
+}
+
+@Composable
+private fun SettingsContent(
+    uiState: SettingsUiState,
+    onChooseDirectoryClick: () -> Unit,
+    onResetExportDirClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val folderName = remember(uiState.exportDirUri) {
+        extractFolderName(uiState.exportDirUri)
+    }
+
+    Column(
+        modifier
+            .fillMaxSize()
+            .padding(20.dp)
+    ) {
+        DirectorySettingItem(
+            label = "Export directory",
+            folderName = folderName,
+            onClick = onChooseDirectoryClick
+        )
+
+        Spacer(Modifier.height(12.dp))
+
+        if (uiState.exportDirUri != null) {
+            OutlinedButton(
+                onClick = onResetExportDirClick,
+                border = BorderStroke(1.dp, MaterialTheme.colorScheme.primary),
+            ) {
+                Text("Reset to default")
+            }
+        }
+    }
+}
+
+@Composable
+fun DirectorySettingItem(
+    label: String,
+    folderName: String,
+    onClick: () -> Unit,
+) {
+    Column {
+        Text(
+            text = label,
+            style = MaterialTheme.typography.titleLarge
+        )
+
+        Spacer(Modifier.height(8.dp))
+
+        Card(
+            modifier = Modifier
+                .fillMaxWidth()
+                .clickable(onClick = onClick),
+            shape = MaterialTheme.shapes.medium
+        ) {
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp, vertical = 14.dp),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Text(
+                    text = folderName,
+                    style = MaterialTheme.typography.bodyLarge
+                )
+
+                Icon(
+                    Icons.Default.Folder,
+                    contentDescription = "Change directory",
+                )
+            }
+        }
+    }
+}
+
+private fun extractFolderName(uriString: String?): String {
+    if (uriString == null) return "Downloads (default)"
+    return runCatching {
+        val uri = uriString.toUri()
+        uri.lastPathSegment?.substringAfter(':')?.substringAfter('/') ?: uriString
+    }.getOrElse { uriString }
+}
+
+@Preview
+@Composable
+fun SettingsScreenPreviewWithoutDir() {
+    SettingsScreenPreview(SettingsUiState(null))
+}
+
+@Preview
+@Composable
+fun SettingsScreenPreviewWithDir() {
+    SettingsScreenPreview(SettingsUiState("content://root/dir"))
+}
+
+@Composable
+fun SettingsScreenPreview(uiState: SettingsUiState) {
+    FairScanTheme {
+        SettingsScreen(uiState, onChooseDirectoryClick = {}, onResetExportDirClick = {}, onBack= {})
+    }
+}

app/src/main/java/org/fairscan/app/ui/screens/settings/SettingsViewModel.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.app.ui.screens.settings
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+import org.fairscan.app.AppContainer
+
+data class SettingsUiState(
+    val exportDirUri: String? = null
+)
+
+class SettingsViewModel(container: AppContainer) : ViewModel() {
+
+    private val repo = container.settingsRepository
+
+    val uiState: StateFlow<SettingsUiState> =
+        repo.exportDirUri
+            .map { uri -> SettingsUiState(exportDirUri = uri) }
+            .stateIn(
+                viewModelScope,
+                SharingStarted.WhileSubscribed(5000),
+                SettingsUiState()
+            )
+
+    fun setExportDirUri(uri: String?) {
+        viewModelScope.launch {
+            repo.setExportDirUri(uri)
+        }
+    }
+}

gradle/libs.versions.toml

@@ -10,7 +10,7 @@ lifecycleRuntimeKtx = "2.9.3"
 activityCompose = "1.10.1"
 composeBom = "2025.08.01"
 camerax = "1.4.2"
-datastore = "1.1.7"
+datastore = "1.2.0"
 litert = "1.4.0"
 opencv = "4.12.0"
 assertj = "3.27.4"
@@ -46,6 +46,7 @@ androidx-camera-camera2 = { group = "androidx.camera", name = "camera-camera2",
 androidx-camera-lifecycle = { group = "androidx.camera", name = "camera-lifecycle", version.ref = "camerax" }
 androidx-camera-view = { group = "androidx.camera", name = "camera-view", version.ref = "camerax" }
 androidx-datastore = { group = "androidx.datastore", name = "datastore" , version.ref = "datastore" }
+androidx-datastore-preferences = { group = "androidx.datastore", name = "datastore-preferences" , version.ref = "datastore" }
 protobuf-javalite = { group = "com.google.protobuf", name="protobuf-javalite", version.ref = "protobufJavaLite"}
 litert = { group = "com.google.ai.edge.litert", name = "litert", version.ref = "litert" }
 litert-support = { group = "com.google.ai.edge.litert", name = "litert-support", version.ref = "litert" }