This commit introduces the ability to select multiple measurement entries in the table view. Users can now perform batch operations like deleting, exporting, or changing the assigned user for the selected items.

android_app/app/src/main/java/com/health/openscale/core/facade/DataManagementFacade.kt

@@ -90,8 +90,9 @@ class DataManagementFacade @Inject constructor(
     suspend fun exportUserToCsv(
         userId: Int,
         uri: Uri,
-        resolver: ContentResolver
+        resolver: ContentResolver,
-    ): Result<Int> = importExport.exportUserToCsv(userId, uri, resolver)
+        filterByMeasurementIds: List<Int>? = null
+    ): Result<Int> = importExport.exportUserToCsv(userId, uri, resolver, filterByMeasurementIds)
 
     suspend fun importUserFromCsv(
         userId: Int,

android_app/app/src/main/java/com/health/openscale/core/usecase/ImportExportUseCases.kt

@@ -91,7 +91,8 @@ class ImportExportUseCases @Inject constructor(
     suspend fun exportUserToCsv(
         userId: Int,
         uri: Uri,
-        contentResolver: ContentResolver
+        contentResolver: ContentResolver,
+        filterByMeasurementIds: List<Int>? = null
     ): Result<Int> = runCatching {
         LogManager.i(TAG, "CSV export for userId=$userId -> $uri")
 
@@ -120,15 +121,21 @@ class ImportExportUseCases @Inject constructor(
             addAll(valueColumnKeys.sorted())
         }
 
-        val userMeasurementsWithValues: List<MeasurementWithValues> =
+        val allUserMeasurementsWithValues: List<MeasurementWithValues> =
             repository.getMeasurementsWithValuesForUser(userId).first()
 
-        require(userMeasurementsWithValues.isNotEmpty()) {
+        val filteredUserMeasurementsWithValues = if (filterByMeasurementIds != null) {
+            allUserMeasurementsWithValues.filter { it.measurement.id in filterByMeasurementIds }
+        } else {
+            allUserMeasurementsWithValues
+        }
+
+        require(filteredUserMeasurementsWithValues.isNotEmpty()) {
             "No measurements found for userId=$userId"
         }
 
         val rows = mutableListOf<Map<String, String?>>()
-        userMeasurementsWithValues.forEach { mwv ->
+        filteredUserMeasurementsWithValues.forEach { mwv ->
             val zdt = Instant.ofEpochMilli(mwv.measurement.timestamp).atZone(ZoneId.systemDefault())
             val row = mutableMapOf<String, String?>(
                 dateColumnKey to dateFormatter.format(zdt),

android_app/app/src/main/java/com/health/openscale/ui/navigation/AppNavigation.kt

@@ -179,6 +179,7 @@ fun AppNavigation(sharedViewModel: SharedViewModel) {
     // Collect UI states from SharedViewModel
     val topBarTitleFromVM by sharedViewModel.topBarTitle.collectAsState()
     val topBarActions by sharedViewModel.topBarActions.collectAsState()
+    val isInContextualSelectionMode by sharedViewModel.isInContextualSelectionMode.collectAsState()
     val allUsers by sharedViewModel.allUsers.collectAsState()
     val selectedUser by sharedViewModel.selectedUser.collectAsState()
 
@@ -536,7 +537,7 @@ fun AppNavigation(sharedViewModel: SharedViewModel) {
                         }
 
                         // Show user switcher dropdown if on a main route and users exist.
-                        if (currentRoute in mainRoutes && allUsers.isNotEmpty() && currentRoute != Routes.SETTINGS) {
+                        if (!isInContextualSelectionMode && currentRoute in mainRoutes && allUsers.isNotEmpty() && currentRoute != Routes.SETTINGS) {
                             UserDropdownAsAction(
                                 users = allUsers,
                                 selectedUser = selectedUser,

android_app/app/src/main/java/com/health/openscale/ui/screen/overview/MeasurementDetailScreen.kt

@@ -49,6 +49,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateMapOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -77,6 +78,7 @@ import com.health.openscale.ui.screen.dialog.TextInputDialog
 import com.health.openscale.ui.screen.dialog.TimeInputDialog
 import com.health.openscale.ui.screen.dialog.UserInputDialog
 import com.health.openscale.ui.shared.TopBarAction
+import kotlinx.coroutines.launch
 import java.text.DateFormat
 import java.text.SimpleDateFormat
 import java.util.Calendar
@@ -100,6 +102,7 @@ fun MeasurementDetailScreen(
     sharedViewModel: SharedViewModel
 ) {
     val context = LocalContext.current
+    val scope = rememberCoroutineScope()
 
     // Holds the string representation of measurement values, keyed by MeasurementType ID.
     val valuesState = remember { mutableStateMapOf<Int, String>() }
@@ -311,7 +314,9 @@ fun MeasurementDetailScreen(
                         }
 
                     if (allConversionsOk) {
-                        sharedViewModel.saveMeasurement(measurementToSave, valueList)
+                        scope.launch {
+                            sharedViewModel.saveMeasurement(measurementToSave, valueList)
+                        }
                         pendingUserId = null
                         isPendingNavigation = true // Trigger loading indicator and navigate back.
                         navController.popBackStack()

android_app/app/src/main/java/com/health/openscale/ui/screen/overview/OverviewScreen.kt

@@ -757,7 +757,9 @@ fun OverviewScreen(
                                             )
                                         },
                                         onDelete = {
-                                            sharedViewModel.deleteMeasurement(enrichedItem.measurementWithValues.measurement)
+                                            scope.launch {
+                                                sharedViewModel.deleteMeasurement(enrichedItem.measurementWithValues.measurement)
+                                            }
                                         },
                                         isHighlighted = (highlightedMeasurementId == enrichedItem.measurementWithValues.measurement.id)
                                     )

android_app/app/src/main/java/com/health/openscale/ui/screen/table/TableScreen.kt

@@ -14,6 +14,10 @@
  */
 package com.health.openscale.ui.screen.table
 
+import android.net.Uri
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
@@ -37,22 +41,35 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowDownward
 import androidx.compose.material.icons.filled.ArrowUpward
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.FileDownload
+import androidx.compose.material.icons.filled.SupervisorAccount
+import androidx.compose.material.icons.outlined.CheckBox
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Checkbox
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TriStateCheckbox
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateListOf
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.state.ToggleableState
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
@@ -61,6 +78,7 @@ import androidx.navigation.NavController
 import com.health.openscale.R
 import com.health.openscale.core.data.EvaluationState
 import com.health.openscale.core.data.InputFieldType
+import com.health.openscale.core.data.MeasurementTypeIcon
 import com.health.openscale.core.data.MeasurementTypeKey
 import com.health.openscale.core.data.Trend
 import com.health.openscale.core.data.UnitType
@@ -68,8 +86,12 @@ import com.health.openscale.ui.navigation.Routes
 import com.health.openscale.ui.screen.components.MeasurementTypeFilterRow
 import com.health.openscale.ui.shared.SharedViewModel
 import com.health.openscale.core.utils.LocaleUtils
+import com.health.openscale.ui.screen.dialog.UserInputDialog
+import com.health.openscale.ui.shared.TopBarAction
+import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.launch
 import java.text.DateFormat
+import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
 
@@ -125,6 +147,7 @@ fun TableScreen(
     navController: NavController,
     sharedViewModel: SharedViewModel
 ) {
+    val context = LocalContext.current
     val scope = rememberCoroutineScope()
     val enrichedMeasurements by sharedViewModel.enrichedMeasurementsFlow.collectAsState()
     val allAvailableTypesFromVM by sharedViewModel.measurementTypes.collectAsState()
@@ -132,12 +155,35 @@ fun TableScreen(
 
     // Column selection state provided by filter row.
     val selectedColumnIdsFromFilter = remember { mutableStateListOf<Int>() }
+    var isInSelectionMode by rememberSaveable { mutableStateOf(false) }
+    val selectedItemIds = remember { mutableStateListOf<Int>() }
+    val allUsersForDialog by sharedViewModel.allUsers.collectAsState()
+
+    var showDeleteConfirmDialog by rememberSaveable { mutableStateOf(false) }
+    var showChangeUserDialog by rememberSaveable { mutableStateOf(false) }
 
     val displayedTypes =
         remember(allAvailableTypesFromVM, selectedColumnIdsFromFilter.toList()) {
             allAvailableTypesFromVM.filter { it.id in selectedColumnIdsFromFilter }
         }
 
+    val exportCsvLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.CreateDocument("text/csv"),
+        onResult = { uri: Uri? ->
+            val currentUserId = sharedViewModel.selectedUserId.value
+            if (uri != null && selectedItemIds.isNotEmpty() && currentUserId != null && currentUserId != 0) {
+                sharedViewModel.performCsvExport(
+                    userId = currentUserId,
+                    uri = uri,
+                    contentResolver = context.contentResolver,
+                    filterByMeasurementIds = selectedItemIds.toList()
+                )
+                isInSelectionMode = false
+                selectedItemIds.clear()
+            }
+        }
+    )
+
     // Transform measurements -> table rows (compute eval state & formatted strings here).
     val tableData = remember(enrichedMeasurements, displayedTypes, allAvailableTypesFromVM, userEvaluationContext) {
         if (enrichedMeasurements.isEmpty() || displayedTypes.isEmpty()) {
@@ -253,8 +299,233 @@ fun TableScreen(
     val noDataForSelectionMessage = stringResource(id = R.string.table_message_no_data_for_selection)
     val dateColumnHeader = stringResource(id = R.string.table_header_date)
 
-    LaunchedEffect(Unit, tableScreenTitle) {
+    fun deleteSelectedItems(selectedItemIds : List<Int>) {
-        sharedViewModel.setTopBarTitle(tableScreenTitle)
+        if (selectedItemIds.isEmpty()) {
+            return
+        }
+
+        scope.launch {
+            var allSucceeded = true
+
+            for (id in selectedItemIds) {
+                val measurementWithValues = sharedViewModel.getMeasurementById(id).firstOrNull()
+
+                if (measurementWithValues != null) {
+                    val success = sharedViewModel.deleteMeasurement(measurementWithValues.measurement, true)
+
+                    if (!success) {
+                        allSucceeded = false
+                        break
+                    }
+                }
+            }
+
+            if (allSucceeded) {
+                sharedViewModel.showSnackbar(messageResId = R.string.snackbar_items_deleted_successfully, formatArgs = listOf(selectedItemIds.size))
+            } else {
+                sharedViewModel.showSnackbar(messageResId = R.string.snackbar_error_deleting_items)
+            }
+        }
+    }
+
+    fun exportSelectedItems(selectedItemIds: List<Int>) {
+        if (selectedItemIds.isEmpty()) {
+            return
+        }
+
+        val timestamp = SimpleDateFormat("yyyyMMdd", Locale.getDefault()).format(Date())
+        val fileName = "${timestamp}_openscale_selected_export.csv"
+        exportCsvLauncher.launch(fileName)
+    }
+
+    fun changeUserOfSelectedItems(selectedItemIds : List<Int>, newUserId : Int) {
+        if (selectedItemIds.isEmpty()) {
+            return
+        }
+
+        scope.launch {
+            var allSucceeded = true
+
+            for (id in selectedItemIds) {
+                val measurementWithValues = sharedViewModel.getMeasurementById(id).firstOrNull()
+
+                if (measurementWithValues != null) {
+                    val originalMeasurement = measurementWithValues.measurement
+                    val originalValues = measurementWithValues.values.map { it.value }
+
+                    val updatedMeasurement = originalMeasurement.copy(userId = newUserId)
+
+                    val success = sharedViewModel.saveMeasurement(updatedMeasurement, originalValues, true)
+
+                    if (!success) {
+                        allSucceeded = false
+                        break
+                    }
+                }
+            }
+
+            if (allSucceeded) {
+                sharedViewModel.showSnackbar(messageResId = R.string.snackbar_items_user_changed_successfully, formatArgs = listOf(selectedItemIds.size))
+            } else {
+                sharedViewModel.showSnackbar(messageResId = R.string.snackbar_error_user_changed_items)
+            }
+        }
+    }
+
+    if (showChangeUserDialog) {
+        val usersForDialog = allUsersForDialog.filter { user ->
+            user.id != 0 && user.id != sharedViewModel.selectedUserId.value
+        }
+        if (usersForDialog.isNotEmpty()) {
+            UserInputDialog(
+                title = stringResource(R.string.dialog_title_select_user_for_assignment),
+                users = usersForDialog,
+                initialSelectedId = usersForDialog.firstOrNull()?.id,
+                measurementIcon = MeasurementTypeIcon.IC_USER,
+                iconBackgroundColor = MaterialTheme.colorScheme.primary,
+                onDismiss = {
+                    showChangeUserDialog = false
+                },
+                onConfirm = { selectedNewUserId ->
+                    if (selectedNewUserId != null) {
+                        changeUserOfSelectedItems(selectedItemIds.toList(), selectedNewUserId)
+                    }
+                    showChangeUserDialog = false
+                    isInSelectionMode = false
+                    selectedItemIds.clear()
+                }
+            )
+        } else {
+            LaunchedEffect(Unit) {
+                showChangeUserDialog = false
+                sharedViewModel.showSnackbar(messageResId = R.string.snackbar_no_other_users_to_change_to)
+            }
+        }
+    }
+
+    if (showDeleteConfirmDialog) {
+        AlertDialog(
+            onDismissRequest = {
+                showDeleteConfirmDialog = false
+            },
+            title = {
+                Text(text = stringResource(id = R.string.dialog_title_delete_items))
+            },
+            text = {
+                val messageResId = if (selectedItemIds.size == 1) {
+                    R.string.dialog_message_delete_item
+                } else {
+                    R.string.dialog_message_delete_items
+                }
+                Text(text = stringResource(id = messageResId, selectedItemIds.size))
+            },
+            confirmButton = {
+                TextButton(
+                    onClick = {
+                        deleteSelectedItems(selectedItemIds.toList())
+                        showDeleteConfirmDialog = false
+                        isInSelectionMode = false
+                        selectedItemIds.clear()
+                    }
+                ) {
+                    Text(stringResource(id = R.string.delete_button_label).uppercase(Locale.getDefault()))
+                }
+            },
+            dismissButton = {
+                TextButton(
+                    onClick = {
+                        showDeleteConfirmDialog = false
+                    }
+                ) {
+                    Text(stringResource(id = R.string.cancel_button).uppercase(Locale.getDefault()))
+                }
+            },
+            icon = {
+                Icon(Icons.Filled.Delete, contentDescription = null, tint = MaterialTheme.colorScheme.error)
+            }
+        )
+    }
+
+    LaunchedEffect(Unit, tableScreenTitle, isInSelectionMode, selectedItemIds.toList(), enrichedMeasurements) {
+        sharedViewModel.setContextualSelectionMode(isInSelectionMode)
+
+        if (isInSelectionMode) {
+            sharedViewModel.setTopBarTitle(context.getString(R.string.items_selected_count, selectedItemIds.size))
+
+            val actions = mutableListOf<TopBarAction>()
+
+            actions.add(
+                TopBarAction(
+                    icon = Icons.Filled.SupervisorAccount,
+                    contentDescriptionResId = R.string.desc_change_user,
+                    onClick = {
+                        val usersSelectable = allUsersForDialog.filter { it.id != 0 && it.id != sharedViewModel.selectedUser.value?.id }
+
+                        if (usersSelectable.isNotEmpty()) {
+                            showChangeUserDialog = true
+                        } else {
+                            sharedViewModel.showSnackbar(messageResId = R.string.snackbar_no_other_users_to_change_to)
+                        }
+                    }
+                )
+            )
+            actions.add(
+                TopBarAction(
+                    icon = Icons.Filled.FileDownload,
+                    contentDescriptionResId = R.string.desc_export_selected,
+                    onClick = {
+                        exportSelectedItems(selectedItemIds)
+                    }
+                )
+            )
+            actions.add(
+                TopBarAction(
+                    icon = Icons.Filled.Delete,
+                    contentDescriptionResId = R.string.desc_delete_selected,
+                    onClick = {
+                        if (selectedItemIds.isNotEmpty()) {
+                            showDeleteConfirmDialog = true
+                        }
+                    }
+                )
+            )
+
+            actions.add(
+                TopBarAction(
+                    icon = Icons.Filled.Close,
+                    contentDescriptionResId = R.string.desc_cancel_selection_mode,
+                    onClick = {
+                        isInSelectionMode = false
+                        selectedItemIds.clear()
+                    }
+                )
+            )
+
+            sharedViewModel.setTopBarActions(actions)
+
+        } else {
+            sharedViewModel.setTopBarTitle(tableScreenTitle)
+
+            val defaultActions = mutableListOf<TopBarAction>()
+            if (!enrichedMeasurements.isEmpty()) {
+                defaultActions.add(
+                    TopBarAction(
+                        icon = Icons.Outlined.CheckBox,
+                        contentDescriptionResId = R.string.desc_enter_selection_mode,
+                        onClick = { isInSelectionMode = true }
+                    )
+                )
+            }
+
+            sharedViewModel.setTopBarActions(defaultActions)
+        }
+    }
+
+    if (isInSelectionMode) {
+        BackHandler(enabled = true) {
+            isInSelectionMode = false
+            selectedItemIds.clear()
+        }
     }
 
     val horizontalScrollState = rememberScrollState()
@@ -271,7 +542,14 @@ fun TableScreen(
             onPersistSelectedTypeIds = { idsToSave ->
                 scope.launch { sharedViewModel.saveSelectedTableTypeIds(idsToSave) }
             },
-            filterLogic = { allTypes -> allTypes.filter { it.isEnabled } },
+            filterLogic = { allTypes ->
+                allTypes.filter {
+                    it.isEnabled &&
+                    it.key != MeasurementTypeKey.DATE &&
+                    it.key != MeasurementTypeKey.TIME &&
+                    it.key != MeasurementTypeKey.USER
+                }
+            },
             defaultSelectionLogic = { availableFilteredTypes ->
                 val defaultDesiredTypeIds = listOf(
                     MeasurementTypeKey.WEIGHT.id,
@@ -337,6 +615,40 @@ fun TableScreen(
                         .height(IntrinsicSize.Min),
                     verticalAlignment = Alignment.CenterVertically
                 ) {
+                    if (isInSelectionMode) {
+                        val allItemsSelected = tableData.isNotEmpty() && selectedItemIds.size == tableData.size
+                        val noItemsSelected = selectedItemIds.isEmpty()
+
+                        val checkboxState = when {
+                            allItemsSelected -> ToggleableState.On
+                            noItemsSelected -> ToggleableState.Off
+                            else -> ToggleableState.Indeterminate
+                        }
+
+                        Box(modifier = Modifier
+                            .fillMaxHeight()
+                            .padding(horizontal = 6.dp),
+                            contentAlignment = Alignment.CenterStart
+                        ) {
+                            TriStateCheckbox(
+                                state = checkboxState,
+                                onClick = {
+                                    when (checkboxState) {
+                                        ToggleableState.On -> selectedItemIds.clear()
+                                        ToggleableState.Off -> {
+                                            selectedItemIds.clear()
+                                            selectedItemIds.addAll(tableData.map { it.measurementId })
+                                        }
+                                        ToggleableState.Indeterminate -> {
+                                            selectedItemIds.clear()
+                                            selectedItemIds.addAll(tableData.map { it.measurementId })
+                                        }
+                                    }
+                                }
+                            )
+                        }
+                    }
+
                     TableHeaderCellInternal(
                         text = dateColumnHeader,
                         modifier = Modifier
@@ -368,27 +680,63 @@ fun TableScreen(
                 // --- DATA ROWS ---
                 LazyColumn(Modifier.fillMaxSize()) {
                     items(tableData, key = { it.measurementId }) { rowData ->
+                        val isSelected = selectedItemIds.contains(rowData.measurementId)
+
                         Row(
                             Modifier
                                 .fillMaxWidth()
+                                .background(
+                                    if (isSelected && isInSelectionMode) {
+                                        MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.3f)
+                                    } else {
+                                        MaterialTheme.colorScheme.surface
+                                    }
+                                )
                                 .clickable {
-                                    navController.navigate(
+                                    if (isInSelectionMode) {
-                                        Routes.measurementDetail(
+                                        if (isSelected) {
-                                            rowData.measurementId,
+                                            selectedItemIds.remove(rowData.measurementId)
-                                            sharedViewModel.selectedUserId.value
+                                        } else {
+                                            selectedItemIds.add(rowData.measurementId)
+                                        }
+                                    } else {
+                                        navController.navigate(
+                                            Routes.measurementDetail(
+                                                rowData.measurementId,
+                                                sharedViewModel.selectedUserId.value
+                                            )
                                         )
-                                    )
+                                    }
                                 }
                                 .height(IntrinsicSize.Min),
                             verticalAlignment = Alignment.CenterVertically
                         ) {
                             // Date cell (fixed column)
+                            if (isInSelectionMode) {
+                                Box(
+                                    modifier = Modifier
+                                        .fillMaxHeight()
+                                        .padding(horizontal = 6.dp),
+                                    contentAlignment = Alignment.CenterStart
+                                ) {
+                                    Checkbox(
+                                        checked = isSelected,
+                                        onCheckedChange = { checked ->
+                                            if (checked) {
+                                                selectedItemIds.add(rowData.measurementId)
+                                            } else {
+                                                selectedItemIds.remove(rowData.measurementId)
+                                            }
+                                        }
+                                    )
+                                }
+                            }
+
                             TableDataCellInternal(
                                 cellData = null,
                                 fixedText = rowData.formattedTimestamp,
                                 modifier = Modifier
                                     .widthIn(min = dateColMin, max = dateColMax)
-                                    .background(MaterialTheme.colorScheme.surface)
                                     .fillMaxHeight(),
                                 alignment = TextAlign.Start,
                                 isDateCell = true

android_app/app/src/main/java/com/health/openscale/ui/shared/SharedViewModel.kt

@@ -17,6 +17,9 @@
  */
 package com.health.openscale.ui.shared
 
+import android.content.ContentResolver
+import android.net.Uri
+import android.util.Log
 import androidx.annotation.StringRes
 import androidx.compose.material3.SnackbarDuration
 import androidx.lifecycle.ViewModel
@@ -30,6 +33,7 @@ import com.health.openscale.core.data.SmoothingAlgorithm
 import com.health.openscale.core.data.TimeRangeFilter
 import com.health.openscale.core.data.User
 import com.health.openscale.core.data.UserGoals
+import com.health.openscale.core.facade.DataManagementFacade
 import com.health.openscale.core.facade.MeasurementFacade
 import com.health.openscale.core.facade.SettingsFacade
 import com.health.openscale.core.facade.UserFacade
@@ -38,6 +42,8 @@ import com.health.openscale.core.model.MeasurementWithValues
 import com.health.openscale.core.model.UserEvaluationContext
 import com.health.openscale.core.usecase.MeasurementEvaluationResult
 import com.health.openscale.core.utils.LogManager
+import com.health.openscale.core.utils.LogManager.init
+import com.health.openscale.ui.screen.settings.SettingsViewModel
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
@@ -52,12 +58,14 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.emptyFlow
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import kotlinx.coroutines.withTimeoutOrNull
 import java.util.concurrent.atomic.AtomicBoolean
 import javax.inject.Inject
@@ -71,6 +79,7 @@ import javax.inject.Inject
 class SharedViewModel @Inject constructor(
     private val userFacade: UserFacade,
     private val measurementFacade: MeasurementFacade,
+    private val dataManagementFacade: DataManagementFacade,
     private val settingsFacade: SettingsFacade
 ) : ViewModel(), SettingsFacade by settingsFacade {
     companion object {
@@ -94,6 +103,13 @@ class SharedViewModel @Inject constructor(
     fun setTopBarAction(action: TopBarAction?) { _topBarActions.value = if (action != null) listOf(action) else emptyList() }
     fun setTopBarActions(actions: List<TopBarAction>) { _topBarActions.value = actions }
 
+    private val _isInContextualSelectionMode = MutableStateFlow(false)
+    val isInContextualSelectionMode: StateFlow<Boolean> = _isInContextualSelectionMode.asStateFlow()
+
+    fun setContextualSelectionMode(isActive: Boolean) {
+        _isInContextualSelectionMode.value = isActive
+    }
+
     // --- Snackbar events ---
     private val _snackbarEvents = MutableSharedFlow<SnackbarEvent>(replay = 0, extraBufferCapacity = 1)
     val snackbarEvents: SharedFlow<SnackbarEvent> = _snackbarEvents.asSharedFlow()
@@ -280,6 +296,19 @@ class SharedViewModel @Inject constructor(
             }
         }
 
+    fun performCsvExport(userId: Int, uri: Uri, contentResolver: ContentResolver, filterByMeasurementIds: List<Int>? = null) {
+        viewModelScope.launch {
+            try {
+                val rows = dataManagementFacade.exportUserToCsv(userId, uri, contentResolver, filterByMeasurementIds).getOrThrow()
+                if (rows > 0) showSnackbar(messageResId = R.string.export_successful)
+                else showSnackbar(messageResId = R.string.export_error_no_exportable_values)
+            } catch (e: Exception) {
+                LogManager.e(TAG, "CSV export error", e)
+                showSnackbar(messageResId = R.string.export_error_generic, formatArgs = listOf(e.localizedMessage ?: "Unknown error"))
+            }
+        }
+    }
+
     // --- Measurement types (via MeasurementFacade) ---
     val measurementTypes: StateFlow<List<MeasurementType>> =
         measurementFacade.getAllMeasurementTypes()
@@ -339,13 +368,6 @@ class SharedViewModel @Inject constructor(
             .map { list -> list.firstOrNull()?.measurementWithValues }
             .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), null)
 
-    // --- Time-filtered flow (no smoothing) for current user ---
-    fun getTimeFilteredEnrichedMeasurements(range: TimeRangeFilter): Flow<List<EnrichedMeasurement>> =
-        selectedUserId.flatMapLatest { uid ->
-            if (uid == null) flowOf(emptyList())
-            else measurementFacade.timeFilteredEnrichedFlow(uid, measurementTypes, range)
-        }
-
     // --- Full pipeline (time filter + smoothing) for current user ---
     val processedMeasurementsFlow: StateFlow<List<EnrichedMeasurement>> =
         selectedUserId
@@ -364,28 +386,36 @@ class SharedViewModel @Inject constructor(
             .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), emptyList())
 
     // --- CRUD delegates (via MeasurementFacade) ---
-    fun saveMeasurement(measurement: Measurement, values: List<MeasurementValue>) {
+    fun getMeasurementById(id: Int) : Flow<MeasurementWithValues?> {
-        viewModelScope.launch(Dispatchers.IO) {
+        return measurementFacade.getMeasurementWithValuesById(id)
+    }
+
+    suspend fun saveMeasurement(measurement: Measurement, values: List<MeasurementValue>, silent : Boolean = false) : Boolean {
+        return withContext(Dispatchers.IO) {
             val result = measurementFacade.saveMeasurement(measurement, values)
             if (result.isSuccess) {
-                showSnackbar(
+                 if (!silent) showSnackbar(
                     messageResId = if (measurement.id == 0) R.string.success_measurement_saved
                     else R.string.success_measurement_updated
                 )
+                true
             } else {
-                showSnackbar(messageResId = R.string.error_saving_measurement)
+                if (!silent) showSnackbar(messageResId = R.string.error_saving_measurement)
+                false
             }
         }
     }
 
-    fun deleteMeasurement(measurement: Measurement) {
+    suspend fun deleteMeasurement(measurement: Measurement, silent : Boolean = false) : Boolean {
-        viewModelScope.launch(Dispatchers.IO) {
+        return withContext(Dispatchers.IO) {
             val result = measurementFacade.deleteMeasurement(measurement)
             if (result.isSuccess) {
-                showSnackbar(messageResId = R.string.success_measurement_deleted)
+                if (!silent) showSnackbar(messageResId = R.string.success_measurement_deleted)
                 if (_currentMeasurementId.value == measurement.id) _currentMeasurementId.value = null
+                true
             } else {
-                showSnackbar(messageResId = R.string.error_deleting_measurement)
+                if (!silent) showSnackbar(messageResId = R.string.error_deleting_measurement)
+                false
             }
         }
     }

android_app/app/src/main/res/values-de/strings.xml

@@ -378,6 +378,21 @@
     <string name="table_message_no_data_for_selection">Keine Daten für die aktuelle Spaltenauswahl verfügbar.</string>
     <string name="table_trend_up">Trend steigend</string>
     <string name="table_trend_down">Trend fallend</string>
+    <string name="desc_enter_selection_mode">Elemente auswählen</string>
+    <string name="items_selected_count">%1$d ausgewählt</string>
+    <string name="desc_cancel_selection_mode">Auswahl abbrechen</string>
+    <string name="desc_change_user">Nutzer für ausgewählte Elemente wechseln</string>
+    <string name="desc_export_selected">Ausgewählte Elemente exportieren</string>
+    <string name="desc_delete_selected">Ausgewählte Elemente löschen</string>
+    <string name="dialog_title_delete_items">Elemente löschen?</string>
+    <string name="dialog_message_delete_item">Möchten Sie das ausgewählte Element wirklich löschen? Diese Aktion kann nicht rückgängig gemacht werden.</string>
+    <string name="dialog_message_delete_items">Möchten Sie die ausgewählten %1$d Elemente wirklich löschen? Diese Aktion kann nicht rückgängig gemacht werden.</string>
+    <string name="snackbar_items_deleted_successfully">%1$d Elemente erfolgreich gelöscht.</string>
+    <string name="snackbar_error_deleting_items">Fehler beim Löschen der Elemente.</string>
+    <string name="dialog_title_select_user_for_assignment">Nutzer für Zuweisung auswählen</string>
+    <string name="snackbar_no_other_users_to_change_to">Keine anderen Nutzer vorhanden, zu denen gewechselt werden kann.</string>
+    <string name="snackbar_items_user_changed_successfully">Nutzer für %1$d Elemente erfolgreich geändert.</string>
+    <string name="snackbar_error_user_changed_items">Fehler beim Ändern des Nutzers für einige Elemente.</string>
 
     <!-- Statistik-Bildschirm -->
     <string name="statistics_no_relevant_types">Keine relevanten Messarten verfügbar oder für Statistiken konfiguriert.</string>

android_app/app/src/main/res/values/strings.xml

@@ -381,6 +381,21 @@
     <string name="table_message_no_data_for_selection">No data available for the current column selection.</string>
     <string name="table_trend_up">Trending up</string>
     <string name="table_trend_down">Trending down</string>
+    <string name="desc_enter_selection_mode">Select items</string>
+    <string name="items_selected_count">%1$d selected</string>
+    <string name="desc_cancel_selection_mode">Cancel selection</string>
+    <string name="desc_change_user">Change user for selected items</string>
+    <string name="desc_export_selected">Export selected items</string>
+    <string name="desc_delete_selected">Delete selected items</string>
+    <string name="dialog_title_delete_items">Delete Items?</string>
+    <string name="dialog_message_delete_item">Are you sure you want to delete the selected item? This action cannot be undone.</string>
+    <string name="dialog_message_delete_items">Are you sure you want to delete the selected %1$d items? This action cannot be undone.</string>
+    <string name="snackbar_items_deleted_successfully">%1$d items deleted successfully.</string>
+    <string name="snackbar_error_deleting_items">Error deleting items.</string>
+    <string name="dialog_title_select_user_for_assignment">Select User for Assignment</string>
+    <string name="snackbar_no_other_users_to_change_to">No other users available to change to.</string>
+    <string name="snackbar_items_user_changed_successfully">User changed for %1$d items successfully.</string>
+    <string name="snackbar_error_user_changed_items">Error changing user for some items.</string>
 
     <!-- Statistics Screen -->
     <string name="statistics_no_relevant_types">No relevant measurement types available or configured for statistics.</string>