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// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'framework.dart';
import 'inherited_theme.dart';
import 'navigator.dart';
import 'overlay.dart';
/// Builds and manages a context menu at a given location.
/// There can only ever be one context menu shown at a given time in the entire
/// app.
/// {@tool dartpad}
/// This example shows how to use a GestureDetector to show a context menu
/// anywhere in a widget subtree that receives a right click or long press.
/// ** See code in examples/api/lib/material/context_menu/context_menu_controller.0.dart **
/// {@end-tool}
class ContextMenuController {
/// Creates a context menu that can be shown with [show].
/// Called when this menu is removed.
final VoidCallback? onRemove;
/// The currently shown instance, if any.
static ContextMenuController? _shownInstance;
// The OverlayEntry is static because only one context menu can be displayed
// at one time.
static OverlayEntry? _menuOverlayEntry;
/// Shows the given context menu.
/// Since there can only be one shown context menu at a time, calling this
/// will also remove any other context menu that is visible.
void show({
required BuildContext context,
required WidgetBuilder contextMenuBuilder,
Widget? debugRequiredFor,
}) {
final OverlayState overlayState = Overlay.of(
rootOverlay: true,
debugRequiredFor: debugRequiredFor,
final CapturedThemes capturedThemes = InheritedTheme.capture(
from: context,
to: Navigator.maybeOf(context)?.context,
_menuOverlayEntry = OverlayEntry(
builder: (BuildContext context) {
return capturedThemes.wrap(contextMenuBuilder(context));
_shownInstance = this;
/// Remove the currently shown context menu from the UI.
/// Does nothing if no context menu is currently shown.
/// If a menu is removed, and that menu provided an [onRemove] callback when
/// it was created, then that callback will be called.
/// See also:
/// * [remove], which removes only the current instance.
static void removeAny() {
_menuOverlayEntry = null;
if (_shownInstance != null) {
_shownInstance = null;
/// True if and only if this menu is currently being shown.
bool get isShown => _shownInstance == this;
/// Cause the underlying [OverlayEntry] to rebuild during the next pipeline
/// flush.
/// It's necessary to call this function if the output of [contextMenuBuilder]
/// has changed.
/// Errors if the context menu is not currently shown.
/// See also:
/// * [OverlayEntry.markNeedsBuild]
void markNeedsBuild() {
/// Remove this menu from the UI.
/// Does nothing if this instance is not currently shown. In other words, if
/// another context menu is currently shown, that menu will not be removed.
/// This method should only be called once. The instance cannot be shown again
/// after removing. Create a new instance.
/// If an [onRemove] method was given to this instance, it will be called.
/// See also:
/// * [removeAny], which removes any shown instance of the context menu.
void remove() {
if (!isShown) {