147 lines
4.2 KiB
Dart
147 lines
4.2 KiB
Dart
import 'package:flutter/material.dart';
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class CustomTabView extends StatefulWidget {
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final int itemCount;
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final IndexedWidgetBuilder tabBuilder;
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final IndexedWidgetBuilder pageBuilder;
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final ValueChanged<int> onPositionChange;
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final ValueChanged<double> onScroll;
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final int initPosition;
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CustomTabView({
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@required this.itemCount,
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@required this.tabBuilder,
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@required this.pageBuilder,
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this.onPositionChange,
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this.onScroll,
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this.initPosition,
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});
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@override
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_CustomTabsState createState() => _CustomTabsState();
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}
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class _CustomTabsState extends State<CustomTabView>
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with TickerProviderStateMixin {
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TabController controller;
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int _currentCount;
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int _currentPosition;
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@override
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void initState() {
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_currentPosition = widget.initPosition ?? 0;
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controller = TabController(
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length: widget.itemCount,
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vsync: this,
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initialIndex: _currentPosition,
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);
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controller.addListener(onPositionChange);
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controller.animation.addListener(onScroll);
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_currentCount = widget.itemCount;
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super.initState();
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}
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@override
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void didUpdateWidget(CustomTabView oldWidget) {
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if (_currentCount != widget.itemCount) {
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controller.animation.removeListener(onScroll);
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controller.removeListener(onPositionChange);
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controller.dispose();
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if (widget.initPosition != null) {
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_currentPosition = widget.initPosition;
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}
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if (_currentPosition > widget.itemCount - 1) {
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_currentPosition = widget.itemCount - 1;
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_currentPosition = _currentPosition < 0 ? 0 : _currentPosition;
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if (widget.onPositionChange is ValueChanged<int>) {
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WidgetsBinding.instance.addPostFrameCallback((_) {
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if (mounted) {
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widget.onPositionChange(_currentPosition);
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}
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});
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}
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}
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_currentCount = widget.itemCount;
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setState(() {
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controller = TabController(
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length: widget.itemCount,
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vsync: this,
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initialIndex: _currentPosition,
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);
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controller.addListener(onPositionChange);
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controller.animation.addListener(onScroll);
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});
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} else if (widget.initPosition != null) {
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controller.animateTo(widget.initPosition);
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}
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super.didUpdateWidget(oldWidget);
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}
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@override
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void dispose() {
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controller.animation.removeListener(onScroll);
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controller.removeListener(onPositionChange);
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controller.dispose();
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super.dispose();
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}
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@override
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Widget build(BuildContext context) {
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return Column(
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crossAxisAlignment: CrossAxisAlignment.stretch,
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children: <Widget>[
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Container(
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alignment: Alignment.centerLeft,
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height: 50.0,
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padding: EdgeInsets.all(10.0),
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child: TabBar(
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indicatorSize: TabBarIndicatorSize.label,
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labelPadding: EdgeInsets.symmetric(horizontal: 5.0),
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indicatorPadding: EdgeInsets.symmetric(horizontal: 5.0),
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isScrollable: true,
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controller: controller,
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labelColor: Colors.white,
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unselectedLabelColor: Colors.grey[700],
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indicator: BoxDecoration(
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borderRadius: BorderRadius.all(Radius.circular(15)),
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color: Theme.of(context).accentColor,
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),
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tabs: List.generate(
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widget.itemCount,
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(index) => widget.tabBuilder(context, index),
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),
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),
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),
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Expanded(
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child: TabBarView(
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controller: controller,
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children: List.generate(
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widget.itemCount,
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(index) => widget.pageBuilder(context, index),
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),
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),
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),
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],
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);
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}
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onPositionChange() {
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if (!controller.indexIsChanging) {
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_currentPosition = controller.index;
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if (widget.onPositionChange is ValueChanged<int>) {
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widget.onPositionChange(_currentPosition);
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}
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}
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}
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onScroll() {
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if (widget.onScroll is ValueChanged<double>) {
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widget.onScroll(controller.animation.value);
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}
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}
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}
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