import 'package:flutter/foundation.dart'; import 'package:flutter/rendering.dart'; import 'package:flutter/widgets.dart'; import 'package:flutter/material.dart'; const Duration _kMenuDuration = Duration(milliseconds: 300); const double _kMenuCloseIntervalEnd = 2.0 / 3.0; const double _kMenuMaxWidth = 5.0 * _kMenuWidthStep; const double _kMenuMinWidth = 2.0 * _kMenuWidthStep; const double _kMenuVerticalPadding = 8.0; const double _kMenuWidthStep = 56.0; const double _kMenuScreenPadding = 8.0; class _MenuItem extends SingleChildRenderObjectWidget { const _MenuItem({ Key key, @required this.onLayout, Widget child, }) : assert(onLayout != null), super(key: key, child: child); final ValueChanged onLayout; @override RenderObject createRenderObject(BuildContext context) { return _RenderMenuItem(onLayout); } @override void updateRenderObject( BuildContext context, covariant _RenderMenuItem renderObject) { renderObject.onLayout = onLayout; } } class _RenderMenuItem extends RenderShiftedBox { _RenderMenuItem(this.onLayout, [RenderBox child]) : assert(onLayout != null), super(child); ValueChanged onLayout; @override void performLayout() { if (child == null) { size = Size.zero; } else { child.layout(constraints, parentUsesSize: true); size = constraints.constrain(child.size); } final childParentData = child.parentData as BoxParentData; childParentData.offset = Offset.zero; onLayout(size); } } class _PopupMenu extends StatelessWidget { const _PopupMenu({ Key key, this.route, this.semanticLabel, }) : super(key: key); final _PopupMenuRoute route; final String semanticLabel; @override Widget build(BuildContext context) { final unit = 1.0 / (route.items.length + 1.5); // 1.0 for the width and 0.5 for the last item's fade. final children = []; final popupMenuTheme = PopupMenuTheme.of(context); for (var i = 0; i < route.items.length; i += 1) { final start = (i + 1) * unit; final end = (start + 1.5 * unit).clamp(0.0, 1.0) as double; final opacity = CurvedAnimation( parent: route.animation, curve: Interval(start, end), ); Widget item = route.items[i]; if (route.initialValue != null && route.items[i].represents(route.initialValue)) { item = Container( color: Theme.of(context).highlightColor, child: item, ); } children.add( _MenuItem( onLayout: (size) { route.itemSizes[i] = size; }, child: FadeTransition( opacity: opacity, child: item, ), ), ); } final opacity = CurveTween(curve: const Interval(0.0, 1.0 / 3.0)); final width = CurveTween(curve: Interval(0.0, unit)); final height = CurveTween(curve: Interval(0.0, unit * route.items.length)); final Widget child = ConstrainedBox( constraints: const BoxConstraints( minWidth: _kMenuMinWidth, maxWidth: _kMenuMaxWidth, ), child: IntrinsicWidth( stepWidth: _kMenuWidthStep, child: Semantics( scopesRoute: true, namesRoute: true, explicitChildNodes: true, label: semanticLabel, child: SingleChildScrollView( padding: const EdgeInsets.only(bottom: _kMenuVerticalPadding), child: ListBody(children: children), ), ), ), ); return AnimatedBuilder( animation: route.animation, builder: (context, child) { return Opacity( opacity: opacity.evaluate(route.animation), child: Material( shape: route.shape ?? popupMenuTheme.shape, color: route.color ?? popupMenuTheme.color, type: MaterialType.card, elevation: route.elevation ?? popupMenuTheme.elevation ?? 8.0, child: Align( alignment: AlignmentDirectional.topEnd, widthFactor: width.evaluate(route.animation), heightFactor: height.evaluate(route.animation), child: child, ), ), ); }, child: child, ); } } class _PopupMenuRouteLayout extends SingleChildLayoutDelegate { _PopupMenuRouteLayout(this.position, this.itemSizes, this.selectedItemIndex, this.textDirection); final RelativeRect position; List itemSizes; final int selectedItemIndex; final TextDirection textDirection; @override BoxConstraints getConstraintsForChild(BoxConstraints constraints) { return BoxConstraints.loose( constraints.biggest - const Offset(_kMenuScreenPadding * 2.0, _kMenuScreenPadding * 2.0) as Size, ); } @override Offset getPositionForChild(Size size, Size childSize) { var y = position.top; if (selectedItemIndex != null && itemSizes != null) { var selectedItemOffset = _kMenuVerticalPadding; for (var index = 0; index < selectedItemIndex; index += 1) { selectedItemOffset += itemSizes[index].height; } selectedItemOffset += itemSizes[selectedItemIndex].height / 2; y = position.top + (size.height - position.top - position.bottom) / 2.0 - selectedItemOffset; } double x; if (position.left > position.right) { x = size.width - position.right - childSize.width; } else if (position.left < position.right) { // Menu button is closer to the left edge, so grow to the right, aligned to the left edge. x = position.left; } else { // Menu button is equidistant from both edges, so grow in reading direction. assert(textDirection != null); switch (textDirection) { case TextDirection.rtl: x = size.width - position.right - childSize.width; break; case TextDirection.ltr: x = position.left; break; } } if (x < _kMenuScreenPadding) { x = _kMenuScreenPadding; } else if (x + childSize.width > size.width - _kMenuScreenPadding) { x = size.width - childSize.width - _kMenuScreenPadding; } if (y < _kMenuScreenPadding) { y = _kMenuScreenPadding; } else if (y + childSize.height > size.height - _kMenuScreenPadding) { y = size.height - childSize.height - _kMenuScreenPadding; } return Offset(x, y); } @override bool shouldRelayout(_PopupMenuRouteLayout oldDelegate) { assert(itemSizes.length == oldDelegate.itemSizes.length); return position != oldDelegate.position || selectedItemIndex != oldDelegate.selectedItemIndex || textDirection != oldDelegate.textDirection || !listEquals(itemSizes, oldDelegate.itemSizes); } } class _PopupMenuRoute extends PopupRoute { _PopupMenuRoute({ this.position, this.items, this.initialValue, this.elevation, this.theme, this.popupMenuTheme, this.barrierLabel, this.semanticLabel, this.shape, this.color, this.showMenuContext, this.captureInheritedThemes, }) : itemSizes = List(items.length); final RelativeRect position; final List> items; final List itemSizes; final T initialValue; final double elevation; final ThemeData theme; final String semanticLabel; final ShapeBorder shape; final Color color; final PopupMenuThemeData popupMenuTheme; final BuildContext showMenuContext; final bool captureInheritedThemes; @override Animation createAnimation() { return CurvedAnimation( parent: super.createAnimation(), curve: Curves.linear, reverseCurve: const Interval(0.0, _kMenuCloseIntervalEnd), ); } @override Duration get transitionDuration => _kMenuDuration; @override bool get barrierDismissible => true; @override Color get barrierColor => null; @override final String barrierLabel; @override Widget buildPage(BuildContext context, Animation animation, Animation secondaryAnimation) { int selectedItemIndex; if (initialValue != null) { for (var index = 0; selectedItemIndex == null && index < items.length; index += 1) { if (items[index].represents(initialValue)) selectedItemIndex = index; } } Widget menu = _PopupMenu(route: this, semanticLabel: semanticLabel); if (captureInheritedThemes) { menu = InheritedTheme.captureAll(showMenuContext, menu); } else { if (theme != null) menu = Theme(data: theme, child: menu); } return MediaQuery.removePadding( context: context, removeTop: true, removeBottom: true, removeLeft: true, removeRight: true, child: Builder( builder: (context) { return CustomSingleChildLayout( delegate: _PopupMenuRouteLayout( position, itemSizes, selectedItemIndex, Directionality.of(context), ), child: menu, ); }, ), ); } } Future _showMenu({ @required BuildContext context, @required RelativeRect position, @required List> items, T initialValue, double elevation, String semanticLabel, ShapeBorder shape, Color color, bool captureInheritedThemes = true, bool useRootNavigator = false, }) { assert(context != null); assert(position != null); assert(useRootNavigator != null); assert(items != null && items.isNotEmpty); assert(captureInheritedThemes != null); assert(debugCheckHasMaterialLocalizations(context)); var label = semanticLabel; switch (Theme.of(context).platform) { case TargetPlatform.iOS: case TargetPlatform.macOS: label = semanticLabel; break; case TargetPlatform.android: case TargetPlatform.fuchsia: case TargetPlatform.linux: case TargetPlatform.windows: label = semanticLabel ?? MaterialLocalizations.of(context)?.popupMenuLabel; } return Navigator.of(context, rootNavigator: useRootNavigator) .push(_PopupMenuRoute( position: position, items: items, initialValue: initialValue, elevation: elevation, semanticLabel: label, theme: Theme.of(context, shadowThemeOnly: true), popupMenuTheme: PopupMenuTheme.of(context), barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel, shape: shape, color: color, showMenuContext: context, captureInheritedThemes: captureInheritedThemes, )); } class MyPopupMenuButton extends StatefulWidget { /// Creates a button that shows a popup menu. /// /// The [itemBuilder] argument must not be null. const MyPopupMenuButton({ Key key, @required this.itemBuilder, this.initialValue, this.onSelected, this.onCanceled, this.tooltip, this.elevation, this.padding = const EdgeInsets.all(8.0), this.child, this.icon, this.offset = Offset.zero, this.enabled = true, this.shape, this.color, this.captureInheritedThemes = true, }) : assert(itemBuilder != null), assert(offset != null), assert(enabled != null), assert(captureInheritedThemes != null), assert(!(child != null && icon != null), 'You can only pass [child] or [icon], not both.'), super(key: key); final PopupMenuItemBuilder itemBuilder; final T initialValue; final PopupMenuItemSelected onSelected; final PopupMenuCanceled onCanceled; final String tooltip; final double elevation; final EdgeInsetsGeometry padding; final Widget child; final Widget icon; final Offset offset; final bool enabled; final ShapeBorder shape; final Color color; final bool captureInheritedThemes; @override MyPopupMenuButtonState createState() => MyPopupMenuButtonState(); } class MyPopupMenuButtonState extends State> { void showButtonMenu() { final popupMenuTheme = PopupMenuTheme.of(context); final button = context.findRenderObject() as RenderBox; final overlay = Overlay.of(context).context.findRenderObject() as RenderBox; final position = RelativeRect.fromRect( Rect.fromPoints( button.localToGlobal(widget.offset, ancestor: overlay), button.localToGlobal(button.size.bottomRight(Offset.zero), ancestor: overlay), ), Offset.zero & overlay.size, ); final items = widget.itemBuilder(context); // Only show the menu if there is something to show if (items.isNotEmpty) { _showMenu( context: context, elevation: widget.elevation ?? popupMenuTheme.elevation, items: items, initialValue: widget.initialValue, position: position, shape: widget.shape ?? popupMenuTheme.shape, color: widget.color ?? popupMenuTheme.color, captureInheritedThemes: widget.captureInheritedThemes, ).then((newValue) { if (!mounted) return null; if (newValue == null) { if (widget.onCanceled != null) widget.onCanceled(); return null; } if (widget.onSelected != null) widget.onSelected(newValue); }); } } Icon _getIcon(TargetPlatform platform) { assert(platform != null); switch (platform) { case TargetPlatform.android: case TargetPlatform.fuchsia: return const Icon(Icons.more_vert); case TargetPlatform.iOS: case TargetPlatform.macOS: case TargetPlatform.linux: case TargetPlatform.windows: return const Icon(Icons.more_horiz); } return null; } @override Widget build(BuildContext context) { assert(debugCheckHasMaterialLocalizations(context)); if (widget.child != null) { return Tooltip( message: widget.tooltip ?? MaterialLocalizations.of(context).showMenuTooltip, child: InkWell( onTap: widget.enabled ? showButtonMenu : null, canRequestFocus: widget.enabled, child: widget.child, ), ); } return IconButton( icon: widget.icon ?? _getIcon(Theme.of(context).platform), padding: widget.padding, tooltip: widget.tooltip ?? MaterialLocalizations.of(context).showMenuTooltip, onPressed: widget.enabled ? showButtonMenu : null, ); } } class MyPopupMenuItem extends PopupMenuEntry { const MyPopupMenuItem({ Key key, this.value, this.enabled = true, this.height = kMinInteractiveDimension, this.textStyle, @required this.child, }) : assert(enabled != null), assert(height != null), super(key: key); final int value; final bool enabled; @override final double height; final TextStyle textStyle; final Widget child; @override bool represents(int value) => value == this.value; @override MyPopupMenuItemState> createState() => MyPopupMenuItemState>(); } class MyPopupMenuItemState> extends State { @protected Widget buildChild() => widget.child; @protected void handleTap() { Navigator.pop(context, widget.value); } @override Widget build(BuildContext context) { final theme = Theme.of(context); final popupMenuTheme = PopupMenuTheme.of(context); var style = widget.textStyle ?? popupMenuTheme.textStyle ?? theme.textTheme.subtitle1; Widget item = AnimatedDefaultTextStyle( style: style, duration: kThemeChangeDuration, child: Container( // alignment: AlignmentDirectional.centerStart, // constraints: BoxConstraints(minHeight: widget.height), padding: const EdgeInsets.all(0), child: buildChild(), ), ); return item; // return InkWell( // onTap: widget.enabled ? handleTap : null, // canRequestFocus: widget.enabled, // child: item, // ); } }