GSYGithubAppFlutter-Kotlin资源

import 'dart:async'; import 'dart:ui' show lerpDouble; import 'package:flutter/material.dart'; import 'package:flutter/rendering.dart'; import 'package:flutter/gestures.dart' show DragStartBehavior; const double _kTabHeight = 46.0; const double _kTextAndIconTabHeight = 72.0; /// Defines how the bounds of the selected tab indicator are computed. /// /// See also: /// /// * [TabBar], which displays a row of tabs. /// * [TabBarView], which displays a widget for the currently selected tab. /// * [TabBar.indicator], which defines the appearance of the selected tab /// indicator relative to the tab's bounds. enum TabBarIndicatorSize { /// The tab indicator's bounds are as wide as the space occupied by the tab /// in the tab bar: from the right edge of the previous tab to the left edge /// of the next tab. tab, /// The tab's bounds are only as wide as the (centered) tab widget itself. /// /// This value is used to align the tab's label, typically a [Tab] /// widget's text or icon, with the selected tab indicator. label, } /// A material design [TabBar] tab. /// /// If both [icon] and [text] are provided, the text is displayed below /// the icon. /// /// See also: /// /// * [TabBar], which displays a row of tabs. /// * [TabBarView], which displays a widget for the currently selected tab. /// * [TabController], which coordinates tab selection between a [TabBar] and a [TabBarView]. /// * <https://material.io/design/components/tabs.html> class Tab extends StatelessWidget { /// Creates a material design [TabBar] tab. /// /// At least one of [text], [icon], and [child] must be non-null. The [text] /// and [child] arguments must not be used at the same time. const Tab({ super.key, this.text, this.icon, this.child, }) : assert(text != null || child != null || icon != null), assert(!(text != null && null != child)); /// The text to display as the tab's label. /// /// Must not be used in combination with [child]. final String? text; /// The widget to be used as the tab's label. /// /// Usually a [Text] widget, possibly wrapped in a [Semantics] widget. /// /// Must not be used in combination with [text]. final Widget? child; /// An icon to display as the tab's label. final Widget? icon; Widget _buildLabelText() { return child ?? Text(text!, softWrap: false, overflow: TextOverflow.fade); } @override Widget build(BuildContext context) { assert(debugCheckHasMaterial(context)); double height; Widget? label; if (icon == null) { height = _kTabHeight; label = _buildLabelText(); } else if (text == null && child == null) { height = _kTabHeight; label = icon; } else { height = _kTextAndIconTabHeight; label = Column( mainAxisAlignment: MainAxisAlignment.center, crossAxisAlignment: CrossAxisAlignment.center, children: <Widget>[ Container( margin: const EdgeInsets.only(bottom: 10.0), child: icon, ), _buildLabelText(), ], ); } return SizedBox( height: height, child: Center( widthFactor: 1.0, child: label, ), ); } @override void debugFillProperties(DiagnosticPropertiesBuilder properties) { super.debugFillProperties(properties); properties.add(StringProperty('text', text, defaultValue: null)); properties .add(DiagnosticsProperty<Widget>('icon', icon, defaultValue: null)); } } class _TabStyle extends AnimatedWidget { const _TabStyle({ required Animation<double> animation, this.selected, this.labelColor, this.unselectedLabelColor, this.labelStyle, this.unselectedLabelStyle, required this.child, }) : super(listenable: animation); final TextStyle? labelStyle; final TextStyle? unselectedLabelStyle; final bool? selected; final Color? labelColor; final Color? unselectedLabelColor; final Widget? child; @override Widget build(BuildContext context) { final ThemeData themeData = Theme.of(context); final TabBarThemeData tabBarTheme = TabBarTheme.of(context); final Animation<double> animation = listenable as Animation<double>; // To enable TextStyle.lerp(style1, style2, value), both styles must have // the same value of inherit. Force that to be inherit=true here. final TextStyle defaultStyle = (labelStyle ?? tabBarTheme.labelStyle ?? themeData.primaryTextTheme.bodyLarge)! .copyWith(inherit: true); final TextStyle defaultUnselectedStyle = (unselectedLabelStyle ?? tabBarTheme.unselectedLabelStyle ?? labelStyle ?? themeData.primaryTextTheme.bodyLarge)! .copyWith(inherit: true); final TextStyle textStyle = selected! ? TextStyle.lerp(defaultStyle, defaultUnselectedStyle, animation.value)! : TextStyle.lerp( defaultUnselectedStyle, defaultStyle, animation.value)!; final Color? selectedColor = labelColor ?? tabBarTheme.labelColor ?? themeData.primaryTextTheme.bodyLarge!.color; final Color unselectedColor = unselectedLabelColor ?? tabBarTheme.unselectedLabelColor ?? selectedColor!.withAlpha(0xB2); // 70% alpha final Color? color = selected! ? Color.lerp(selectedColor, unselectedColor, animation.value) : Color.lerp(unselectedColor, selectedColor, animation.value); return DefaultTextStyle( style: textStyle.copyWith(color: color), child: IconTheme.merge( data: IconThemeData( size: 24.0, color: color, ), child: child!, ), ); } } typedef _LayoutCallback = void Function( List<double> xOffsets, TextDirection? textDirection, double width); class _TabLabelBarRenderer extends RenderFlex { _TabLabelBarRenderer({ required super.direction, required super.mainAxisSize, required super.mainAxisAlignment, required super.crossAxisAlignment, required TextDirection super.textDirection, required super.verticalDirection, required this.onPerformLayout, }) : assert(onPerformLayout != null); _LayoutCallback? onPerformLayout; @override void performLayout() { super.performLayout(); // xOffsets will contain childCount+1 values, giving the offsets of the // leading edge of the first tab as the first value, of the leading edge of // the each subsequent tab as each subsequent value, and of the trailing // edge of the last tab as the last value. RenderBox? child = firstChild; final List<double> xOffsets = <double>[]; while (child != null) { final FlexParentData childParentData = child.parentData as FlexParentData; xOffsets.add(childParentData.offset.dx); assert(child.parentData == childParentData); child = childParentData.nextSibling; } assert(textDirection != null); switch (textDirection) { case null: case TextDirection.rtl: xOffsets.insert(0, size.width); break; case TextDirection.ltr: xOffsets.add(size.width); break; } onPerformLayout!(xOffsets, textDirection, size.width); } } // This class and its renderer class only exist to report the widths of the tabs // upon layout. The tab widths are only used at paint time (see _IndicatorPainter) // or in response to input. class _TabLabelBar extends Flex { const _TabLabelBar({ super.children, this.onPerformLayout, }) : super( direction: Axis.horizontal, mainAxisSize: MainAxisSize.max, mainAxisAlignment: MainAxisAlignment.start, crossAxisAlignment: CrossAxisAlignment.center, verticalDirection: VerticalDirection.down, ); final _LayoutCallback? onPerformLayout; @override RenderFlex createRenderObject(BuildContext context) { return _TabLabelBarRenderer( direction: direction, mai