feat: add persistent column width management and horizontal scrolling enhancements in ListDetailScreen

CollabTableAndroid/app/src/main/java/com/collabtable/app/data/preferences/PreferencesManager.kt

@@ -2,6 +2,7 @@ package com.collabtable.app.data.preferences
 
 import android.content.Context
 import android.content.SharedPreferences
+import org.json.JSONObject
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -140,6 +141,38 @@ class PreferencesManager(context: Context) {
         _syncPollIntervalMs.value = clamped
     }
 
+    // Persist per-list column widths (fieldId -> widthDp)
+    // Stored as a JSON object string in SharedPreferences under key: COLUMN_WIDTHS_PREFIX + listId
+    fun getColumnWidths(listId: String): Map<String, Float> {
+        val key = COLUMN_WIDTHS_PREFIX + listId
+        val raw = prefs.getString(key, null) ?: return emptyMap()
+        return try {
+            val json = JSONObject(raw)
+            val map = mutableMapOf<String, Float>()
+            val it = json.keys()
+            while (it.hasNext()) {
+                val fieldId = it.next()
+                val width = json.optDouble(fieldId, Double.NaN)
+                if (!width.isNaN()) {
+                    map[fieldId] = width.toFloat()
+                }
+            }
+            map
+        } catch (e: Exception) {
+            emptyMap()
+        }
+    }
+
+    fun setColumnWidths(listId: String, widthsDp: Map<String, Float>) {
+        val key = COLUMN_WIDTHS_PREFIX + listId
+        val json = JSONObject()
+        widthsDp.forEach { (fieldId, width) ->
+            // Persist as double for precision, value is in dp units
+            json.put(fieldId, width.toDouble())
+        }
+        prefs.edit().putString(key, json.toString()).apply()
+    }
+
     companion object {
         private const val KEY_SERVER_URL = "server_url"
         private const val KEY_FIRST_RUN = "first_run"
@@ -150,6 +183,7 @@ class PreferencesManager(context: Context) {
         private const val KEY_AMOLED_DARK = "amoled_dark"
         private const val KEY_SORT_ORDER = "sort_order"
     private const val KEY_SYNC_POLL_INTERVAL_MS = "sync_poll_interval_ms"
+        private const val COLUMN_WIDTHS_PREFIX = "column_widths_" // + listId
         private const val DEFAULT_SERVER_URL = "http://10.0.2.2:3000/api/"
         private const val DEFAULT_SYNC_POLL_INTERVAL_MS = 250L
         private const val MIN_SYNC_POLL_INTERVAL_MS = 250L

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/ListDetailScreen.kt

@@ -103,6 +103,7 @@ fun ListDetailScreen(
     val context = LocalContext.current
     val database = remember { CollabTableDatabase.getDatabase(context) }
     val viewModel = remember { ListDetailViewModel(database, listId, context) }
+    val prefs = remember { PreferencesManager.getInstance(context) }
 
     val list by viewModel.list.collectAsState()
     val fields by viewModel.fields.collectAsState()
@@ -129,16 +130,19 @@ fun ListDetailScreen(
 
     // Shared scroll state for synchronized horizontal scrolling
     val horizontalScrollState = rememberScrollState()
+    val scope = rememberCoroutineScope()
 
     // Field widths state (resizable columns)
     val fieldWidths = remember { mutableStateMapOf<String, Dp>() }
 
-    // Initialize field widths
+    // Initialize field widths (load persisted per-list widths, fallback to default)
     LaunchedEffect(stableFields) {
+        // Load saved widths for this listId
+        val saved = prefs.getColumnWidths(listId)
         stableFields.forEach { field ->
-            if (!fieldWidths.containsKey(field.id)) {
+            val savedWidth = saved[field.id]?.coerceAtLeast(100f)
-                fieldWidths[field.id] = 150.dp
+            val widthDp = (savedWidth ?: 150f).dp
-            }
+            fieldWidths[field.id] = widthDp
         }
     }
 
@@ -411,6 +415,11 @@ fun ListDetailScreen(
                                     // Enforce only a minimum width; remove the previous max (400dp)
                                     val newWidth = (currentWidth.value + delta).coerceAtLeast(100f)
                                     fieldWidths[field.id] = newWidth.dp
+                                    // Persist updated widths for this listId
+                                    prefs.setColumnWidths(
+                                        listId,
+                                        fieldWidths.mapValues { it.value.value },
+                                    )
                                 },
                                 scrollState = horizontalScrollState,
                                 isLast = (field.id == stableFields.lastOrNull()?.id),
@@ -487,6 +496,28 @@ fun ListDetailScreen(
                                 )
                             }
                         }
+
+                        // Filler area that occupies remaining viewport height and enables horizontal dragging
+                        // to scroll the table even when tapping below the last row on small tables.
+                        item(key = "hscroll_filler") {
+                            Box(
+                                modifier =
+                                    Modifier
+                                        .fillMaxWidth()
+                                        .fillParentMaxHeight()
+                                        .pointerInput(horizontalScrollState) {
+                                            detectDragGestures { change, dragAmount ->
+                                                change.consume()
+                                                val max = horizontalScrollState.maxValue.toFloat()
+                                                val current = horizontalScrollState.value.toFloat()
+                                                val target = (current - dragAmount.x).coerceIn(0f, max)
+                                                // Drag right (positive x) should reveal right side (increase scroll)
+                                                // We subtract dragAmount.x because scrolling value increases when content moves left.
+                                                scope.launch { horizontalScrollState.scrollTo(target.toInt()) }
+                                            }
+                                        },
+                            )
+                        }
                     }
                 }
             }