Flutter: dynamically add tabs and keep state with AutomaticKeepAliveClientMixin












0















I'm trying to create a form with tabs. In each tab I have TextFormField. Tabs have AutomaticKeepAliveClientMixin to keep their State. Tabs can be created dynamically. When new tab is created, it is inserted in the middle of the tabs list.



Problem: when new tab is inserted, its TextFormField keep state of the next tab and so on. It seems states keeps in order from 1 to n. Is there any way to keep the right state for tabs?



Thanks in advance.



import 'package:flutter/material.dart';

class TabTesting extends StatefulWidget {
@override
_TabTestingState createState() => _TabTestingState();
}

class _TabTestingState extends State<TabTesting> with TickerProviderStateMixin {

List<MyTab> _tabs = [
MyTab(TabData("1", "1")),
MyTab(TabData("3", "3")),
];

TabController _tabController;

@override
void initState() {
super.initState();

_tabController = new TabController(vsync: this, length: _tabs.length);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("TabTesting"),
bottom: TabBar(
controller: _tabController,
labelPadding: EdgeInsets.symmetric(vertical: 16.0),
tabs: _tabs.map((tab) => Text(tab.tabData.name)).toList(),
),
),
body: Container(
padding: EdgeInsets.all(32.0),
child: TabBarView(
controller: _tabController,
children: _tabs,
),
),
persistentFooterButtons: <Widget>[
RaisedButton(
child: Text("Add tab"),
onPressed: () {
final newTab = MyTab(TabData("2", "2"));
final newTabs = _tabs;
newTabs.insert(1, newTab);
final index = _tabController.index;
setState(() {
_tabs = newTabs;
_tabController = TabController(
vsync: this,
length: newTabs.length,
initialIndex: index);
});
},
),
],
);
}
}

class MyTab extends StatefulWidget {

final tabData;

MyTab(this.tabData);

@override
_MyTabState createState() => _MyTabState();
}

class _MyTabState extends State<MyTab> with AutomaticKeepAliveClientMixin {

@override
bool get wantKeepAlive => true;

@override
Widget build(BuildContext context) {
return Tab(
child: TextFormField(
decoration: InputDecoration(labelText: widget.tabData.name),
initialValue: widget.tabData.data,
),
);
}
}

class TabData {
String name;
String data;

TabData(this.name, this.data);
}









share|improve this question



























    0















    I'm trying to create a form with tabs. In each tab I have TextFormField. Tabs have AutomaticKeepAliveClientMixin to keep their State. Tabs can be created dynamically. When new tab is created, it is inserted in the middle of the tabs list.



    Problem: when new tab is inserted, its TextFormField keep state of the next tab and so on. It seems states keeps in order from 1 to n. Is there any way to keep the right state for tabs?



    Thanks in advance.



    import 'package:flutter/material.dart';

    class TabTesting extends StatefulWidget {
    @override
    _TabTestingState createState() => _TabTestingState();
    }

    class _TabTestingState extends State<TabTesting> with TickerProviderStateMixin {

    List<MyTab> _tabs = [
    MyTab(TabData("1", "1")),
    MyTab(TabData("3", "3")),
    ];

    TabController _tabController;

    @override
    void initState() {
    super.initState();

    _tabController = new TabController(vsync: this, length: _tabs.length);
    }

    @override
    Widget build(BuildContext context) {
    return Scaffold(
    appBar: AppBar(
    title: Text("TabTesting"),
    bottom: TabBar(
    controller: _tabController,
    labelPadding: EdgeInsets.symmetric(vertical: 16.0),
    tabs: _tabs.map((tab) => Text(tab.tabData.name)).toList(),
    ),
    ),
    body: Container(
    padding: EdgeInsets.all(32.0),
    child: TabBarView(
    controller: _tabController,
    children: _tabs,
    ),
    ),
    persistentFooterButtons: <Widget>[
    RaisedButton(
    child: Text("Add tab"),
    onPressed: () {
    final newTab = MyTab(TabData("2", "2"));
    final newTabs = _tabs;
    newTabs.insert(1, newTab);
    final index = _tabController.index;
    setState(() {
    _tabs = newTabs;
    _tabController = TabController(
    vsync: this,
    length: newTabs.length,
    initialIndex: index);
    });
    },
    ),
    ],
    );
    }
    }

    class MyTab extends StatefulWidget {

    final tabData;

    MyTab(this.tabData);

    @override
    _MyTabState createState() => _MyTabState();
    }

    class _MyTabState extends State<MyTab> with AutomaticKeepAliveClientMixin {

    @override
    bool get wantKeepAlive => true;

    @override
    Widget build(BuildContext context) {
    return Tab(
    child: TextFormField(
    decoration: InputDecoration(labelText: widget.tabData.name),
    initialValue: widget.tabData.data,
    ),
    );
    }
    }

    class TabData {
    String name;
    String data;

    TabData(this.name, this.data);
    }









    share|improve this question

























      0












      0








      0








      I'm trying to create a form with tabs. In each tab I have TextFormField. Tabs have AutomaticKeepAliveClientMixin to keep their State. Tabs can be created dynamically. When new tab is created, it is inserted in the middle of the tabs list.



      Problem: when new tab is inserted, its TextFormField keep state of the next tab and so on. It seems states keeps in order from 1 to n. Is there any way to keep the right state for tabs?



      Thanks in advance.



      import 'package:flutter/material.dart';

      class TabTesting extends StatefulWidget {
      @override
      _TabTestingState createState() => _TabTestingState();
      }

      class _TabTestingState extends State<TabTesting> with TickerProviderStateMixin {

      List<MyTab> _tabs = [
      MyTab(TabData("1", "1")),
      MyTab(TabData("3", "3")),
      ];

      TabController _tabController;

      @override
      void initState() {
      super.initState();

      _tabController = new TabController(vsync: this, length: _tabs.length);
      }

      @override
      Widget build(BuildContext context) {
      return Scaffold(
      appBar: AppBar(
      title: Text("TabTesting"),
      bottom: TabBar(
      controller: _tabController,
      labelPadding: EdgeInsets.symmetric(vertical: 16.0),
      tabs: _tabs.map((tab) => Text(tab.tabData.name)).toList(),
      ),
      ),
      body: Container(
      padding: EdgeInsets.all(32.0),
      child: TabBarView(
      controller: _tabController,
      children: _tabs,
      ),
      ),
      persistentFooterButtons: <Widget>[
      RaisedButton(
      child: Text("Add tab"),
      onPressed: () {
      final newTab = MyTab(TabData("2", "2"));
      final newTabs = _tabs;
      newTabs.insert(1, newTab);
      final index = _tabController.index;
      setState(() {
      _tabs = newTabs;
      _tabController = TabController(
      vsync: this,
      length: newTabs.length,
      initialIndex: index);
      });
      },
      ),
      ],
      );
      }
      }

      class MyTab extends StatefulWidget {

      final tabData;

      MyTab(this.tabData);

      @override
      _MyTabState createState() => _MyTabState();
      }

      class _MyTabState extends State<MyTab> with AutomaticKeepAliveClientMixin {

      @override
      bool get wantKeepAlive => true;

      @override
      Widget build(BuildContext context) {
      return Tab(
      child: TextFormField(
      decoration: InputDecoration(labelText: widget.tabData.name),
      initialValue: widget.tabData.data,
      ),
      );
      }
      }

      class TabData {
      String name;
      String data;

      TabData(this.name, this.data);
      }









      share|improve this question














      I'm trying to create a form with tabs. In each tab I have TextFormField. Tabs have AutomaticKeepAliveClientMixin to keep their State. Tabs can be created dynamically. When new tab is created, it is inserted in the middle of the tabs list.



      Problem: when new tab is inserted, its TextFormField keep state of the next tab and so on. It seems states keeps in order from 1 to n. Is there any way to keep the right state for tabs?



      Thanks in advance.



      import 'package:flutter/material.dart';

      class TabTesting extends StatefulWidget {
      @override
      _TabTestingState createState() => _TabTestingState();
      }

      class _TabTestingState extends State<TabTesting> with TickerProviderStateMixin {

      List<MyTab> _tabs = [
      MyTab(TabData("1", "1")),
      MyTab(TabData("3", "3")),
      ];

      TabController _tabController;

      @override
      void initState() {
      super.initState();

      _tabController = new TabController(vsync: this, length: _tabs.length);
      }

      @override
      Widget build(BuildContext context) {
      return Scaffold(
      appBar: AppBar(
      title: Text("TabTesting"),
      bottom: TabBar(
      controller: _tabController,
      labelPadding: EdgeInsets.symmetric(vertical: 16.0),
      tabs: _tabs.map((tab) => Text(tab.tabData.name)).toList(),
      ),
      ),
      body: Container(
      padding: EdgeInsets.all(32.0),
      child: TabBarView(
      controller: _tabController,
      children: _tabs,
      ),
      ),
      persistentFooterButtons: <Widget>[
      RaisedButton(
      child: Text("Add tab"),
      onPressed: () {
      final newTab = MyTab(TabData("2", "2"));
      final newTabs = _tabs;
      newTabs.insert(1, newTab);
      final index = _tabController.index;
      setState(() {
      _tabs = newTabs;
      _tabController = TabController(
      vsync: this,
      length: newTabs.length,
      initialIndex: index);
      });
      },
      ),
      ],
      );
      }
      }

      class MyTab extends StatefulWidget {

      final tabData;

      MyTab(this.tabData);

      @override
      _MyTabState createState() => _MyTabState();
      }

      class _MyTabState extends State<MyTab> with AutomaticKeepAliveClientMixin {

      @override
      bool get wantKeepAlive => true;

      @override
      Widget build(BuildContext context) {
      return Tab(
      child: TextFormField(
      decoration: InputDecoration(labelText: widget.tabData.name),
      initialValue: widget.tabData.data,
      ),
      );
      }
      }

      class TabData {
      String name;
      String data;

      TabData(this.name, this.data);
      }






      tabs dart flutter state






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      asked Jan 1 at 18:34









      Oleg PlotnikovOleg Plotnikov

      186




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