[shutter] statefulwidget component (pageview component)

One 、PageView Components

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PageView Component constructor : The optional parameter in the constructor is PageView All settable options of the component ;

class PageView extends StatefulWidget { 
      PageView({ 
        Key key,    this.scrollDirection = Axis.horizontal,    this.reverse = false,    PageController controller,    this.physics,    this.pageSnapping = true,    this.onPageChanged,    List<Widget> children = const <Widget>[],    this.dragStartBehavior = DragStartBehavior.start,    this.allowImplicitScrolling = false,    this.restorationId,    this.clipBehavior = Clip.hardEdge,  }) : assert(allowImplicitScrolling != null),       assert(clipBehavior != null),       controller = controller ?? _defaultPageController,       childrenDelegate = SliverChildListDelegate(children),       super(key: key);}

PageView Components children Set up : children Field to set each page component it wants to slide and switch ; In general use Container Encapsulate complex components ;

Code example : The following code is PageView Three sliding switching components are set in , All are Container Components , Every Container Are set in the center , Decorator , Displayed subcomponents Text ;

                    //  Set up a layout container  ,  For encapsulation  PageView  Components                     Container(                      //  Set height                       height: 200,                      //  Set margins                       margin: EdgeInsets.only(top: 10),                      //  Set decoration ,  Dark orange background                       decoration: BoxDecoration(                        color: Colors.deepOrange                      ),                      //  Set up subcomponents  PageView                      child: PageView(                        //  Set up  PageView  Several components encapsulated in                         children: <Widget>[                          //  The first page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.green),                            //  Main text displayed                             child: Text(" page  0", style: TextStyle(fontSize: 20, color: Colors.black),),                          ),                          //  The second page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.red),                            //  Main text displayed                             child: Text(" page  1", style: TextStyle(fontSize: 20, color: Colors.white),),                          ),                          //  The third page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.black),                            //  Main text displayed                             child: Text(" page  2", style: TextStyle(fontSize: 20, color: Colors.yellow),),                          ),                        ],                      ),                    ),

Two 、PageView Component complete code example

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Complete code example :

import 'package:flutter/material.dart';class StatefulWidgetPage extends StatefulWidget { 
      @override  _StatefulWidgetPageState createState() => _StatefulWidgetPageState();}class _StatefulWidgetPageState extends State<StatefulWidgetPage> { 
      ///  The currently selected bottom navigation bar index   int _currentSelectedIndex = 0;  // This widget is the root of your application.  @override  Widget build(BuildContext context) { 
        //  Text component style  ,  Can be set to  Text  Text component     //  Set font size  20,  The color is red     TextStyle textStyle = TextStyle(fontSize: 20, color: Colors.red);    return MaterialApp(      title: 'StatefulWidgetPage  Component example ',      theme: ThemeData(        primarySwatch: Colors.blue,      ),      home: Scaffold(        //  Top title bar         appBar: AppBar(title: Text('StatefulWidgetPage  Component example '),),        //  Bottom navigation bar  BottomNavigationBar  Set up         // items  You can set multiple  BottomNavigationBarItem        bottomNavigationBar: BottomNavigationBar(          //  Set the currently selected bottom navigation index           currentIndex: _currentSelectedIndex,          //  Set the callback event of clicking the navigation bar at the bottom  , index  The parameter is the index value of the click           onTap: (index){ 
                //  Callback  StatefulWidget  Component's  setState  Method of setting state  ,  Modify the currently selected index             //  after  BottomNavigationBar  The component will automatically update the currently selected tab             setState(() { 
                  //  change  int _currentSelectedIndex  The state of the variable               _currentSelectedIndex = index;            });          },          //  entry           items: [          //  Set the bottom navigation bar entry ,  Each entry can be set with an icon           BottomNavigationBarItem(            //  The default icon             icon: Icon(Icons.home, color: Colors.grey,),            //  Icon in active state             activeIcon: Icon(Icons.home, color: Colors.red,),            //  Set title             title: Text(" Home page ")          ),          //  Set the bottom navigation bar entry ,  Each entry can be set with an icon           BottomNavigationBarItem(            //  The default icon             icon: Icon(Icons.settings, color: Colors.grey,),            //  Icon in active state             activeIcon: Icon(Icons.settings, color: Colors.red,),              //  Set title               title: Text(" Set up ")          )        ],),        //  Set the levitation button         floatingActionButton: FloatingActionButton(          onPressed: (){ 
                print(" Click the hover button ");          },          child: Text(" Levitation button assembly "),        ),        // Container  Container usage         body:        _currentSelectedIndex == 0 ?        //  Refresh indicator component         RefreshIndicator(          //  Display content           child: ListView(            children: <Widget>[              Container( //  Corresponding to the bottom navigation bar settings tab                 //  Set the decorator of the container  , BoxDecoration  Is the most commonly used decorator                 //  You can check it by yourself  BoxDecoration  Properties that can be set in                 decoration: BoxDecoration(color: Colors.white),                //  Set up  child  How the sub components are centered ,  Center                 alignment: Alignment.center,                //  Child components ,  The subcomponent is set to a  Column  Components                 child: Column(                  // Column  Child components ,  Set up here  Text  Text component                   children: <Widget>[                    Text(" Main page tab ,  The drop-down refresh "),                    //  Picture components  ,  Load a picture from the network                     Image.network(                        //  Picture address                       "https://img-blog.csdnimg.cn/20210228180808133.png",                      //  Image width                       width: 200,                      //  Picture height                       height: 200,                    ),                    //  Input box components                     TextField(                      //  Set the input box style                       decoration: InputDecoration(                        //  Set content margins ,  The left and right margins are  10,  The upper and lower margins are  0                        contentPadding: EdgeInsets.fromLTRB(10, 0, 10, 0),                        //  Set prompt copywriting information                         hintText: " Prompt information ",                        //  Set prompt copy style                         hintStyle: TextStyle(fontSize: 20, color: Colors.grey),                      ),                    ),                    //  Set up a layout container  ,  For encapsulation  PageView  Components                     Container(                      //  Set height                       height: 200,                      //  Set margins                       margin: EdgeInsets.only(top: 10),                      //  Set decoration ,  Dark orange background                       decoration: BoxDecoration(                        color: Colors.deepOrange                      ),                      //  Set up subcomponents  PageView                      child: PageView(                        //  Set up  PageView  Several components encapsulated in                         children: <Widget>[                          //  The first page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.green),                            //  Main text displayed                             child: Text(" page  0", style: TextStyle(fontSize: 20, color: Colors.black),),                          ),                          //  The second page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.red),                            //  Main text displayed                             child: Text(" page  1", style: TextStyle(fontSize: 20, color: Colors.white),),                          ),                          //  The third page component                           Container(                            //  Set the center mode  ,  centered                             alignment:Alignment.center,                            //  Decorator settings  ,  Green background                             decoration: BoxDecoration(color: Colors.black),                            //  Main text displayed                             child: Text(" page  2", style: TextStyle(fontSize: 20, color: Colors.yellow),),                          ),                        ],                      ),                    ),                  ],                ),              ),            ],          ),          //  Method of callback during refresh           //  When a drop-down operation occurs in the list ,  Call back the method           //  The callback is  Future  Type of           onRefresh: _refreshIndicatorOnRefresh,        )        :        Container( //  Corresponding to the bottom navigation bar settings tab           //  Set the decorator of the container  , BoxDecoration  Is the most commonly used decorator           //  You can check it by yourself  BoxDecoration  Properties that can be set in           decoration: BoxDecoration(color: Colors.white),          //  Set up  child  How the sub components are centered ,  Center           alignment: Alignment.center,          //  Child components ,  The subcomponent is set to a  Column  Components           child: Column(            // Column  Child components ,  Set up here  Text  Text component             children: <Widget>[              Text(" Set up page tabs ")            ],          ),        ) , //  This setting is related to  _currentSelectedIndex == 0?  Corresponding , ?:  Ternary operator       ),    );  }  /// RefreshIndicator  When a pull-down operation occurs ,  Call back the method   ///  This is an asynchronous method  ,  Add... Before the method body  async  keyword   Future<Null> _refreshIndicatorOnRefresh() async{ 
        //  Pause  500 ms ,  Use  await  Keyword implementation     //  Here  500 ms  Between  ,  The list is in refresh state     // 500 ms  after  ,  The list becomes non refreshed     await Future.delayed(Duration(milliseconds: 500));    return null;  }}

Operation effect display :

3、 ... and 、 Related resources

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Reference material :

• Flutter Official website : https://flutter.dev/
• Flutter Developing documents : https://flutter.cn/docs ( Strongly recommend )
• official GitHub Address : https://github.com/flutter
• Flutter The Chinese community : https://flutter.cn/
• Flutter Practical tutorial : https://flutter.cn/docs/cookbook
• Flutter CodeLab : https://codelabs.flutter-io.cn/
• Dart Chinese document : https://dart.cn/
• Dart Developer website : https://api.dart.dev/
• Flutter Chinese net ( unofficial , The translation is very good ) : https://flutterchina.club/ , http://flutter.axuer.com/docs/
• Flutter Related issues : https://flutterchina.club/faq/ ( It is recommended to watch it at the introductory stage )

Blog source download :

• GitHub Address : https://github.com/han1202012/flutter_cmd ( Keep updating with the progress of the blog , There may not be the source code of this blog )

• Blog source snapshot : https://download.csdn.net/download/han1202012/15500147 ( The source code snapshot of this blog , You can find the source code of this blog )