auto hide add new tab button

2026-01-01 08:12:39 +01:00
parent 01d5f70ad0
commit 5495d0c1cd
4 changed files with 170 additions and 45 deletions
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2024-2025 Fabian Freund.
+ *
+ * This file is part of WebLibre
+ * (see https://weblibre.eu).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+/// A hook that manages visibility state based on scroll direction.
+///
+/// Returns a [ValueNotifier<bool>] that automatically updates based on scroll behavior:
+/// - Hides when scrolling down beyond [hideThreshold]
+/// - Shows when scrolling up beyond [showThreshold] or at the top of the scroll view
+/// - Ignores scroll events during [initializationDelay] to prevent hiding during jumpTo/animateTo
+///
+/// Example:
+/// ```dart
+/// final scrollController = useScrollController();
+/// final isVisible = useScrollVisibility(scrollController);
+///
+/// return AnimatedOpacity(
+///   opacity: isVisible.value ? 1.0 : 0.0,
+///   child: FloatingActionButton(...),
+/// );
+/// ```
+ValueNotifier<bool> useScrollVisibility(
+  ScrollController scrollController, {
+  double hideThreshold = 5.0,
+  double showThreshold = 5.0,
+  Duration initializationDelay = const Duration(milliseconds: 1000),
+}) {
+  final isVisible = useState(true);
+  final lastScrollOffset = useRef(0.0);
+  final isInitialized = useRef(false);
+
+  useEffect(() {
+    // Start timer to enable scroll listener after initialization delay
+    final timer = Timer(initializationDelay, () {
+      isInitialized.value = true;
+    });
+
+    void scrollListener() {
+      // Ignore scroll events until initialization is complete
+      if (!isInitialized.value) return;
+
+      final currentOffset = scrollController.offset;
+      final difference = currentOffset - lastScrollOffset.value;
+
+      // Hide when scrolling down beyond threshold
+      if (difference > hideThreshold && isVisible.value) {
+        isVisible.value = false;
+      }
+      // Show when scrolling up beyond threshold or at top
+      else if ((difference < -showThreshold || currentOffset <= 0) &&
+          !isVisible.value) {
+        isVisible.value = true;
+      }
+
+      lastScrollOffset.value = currentOffset;
+    }
+
+    scrollController.addListener(scrollListener);
+    return () {
+      timer.cancel();
+      scrollController.removeListener(scrollListener);
+    };
+  }, [scrollController, hideThreshold, showThreshold, initializationDelay]);
+
+  return isVisible;
+}