内容简介:以下是Demo的总页面和分页面及效果图:逐渐构建,思考,记录完善学习过程,希望后续能够将整个学习的过程整合为一个app,这样既能学习到知识,又能够记录下来。
- 按钮
- 图片及ICON组件
- 单选开关和复选框
- 输入框及表单
- 表单验证
布局类Widget包括:
Row Flex Wrap Stack
路由:
routes: { "new_page": (context) => NewRoute(), // 使用新路由来学习 文本及样式 /* 开始 基础Widget 的学习: */ // 添加一个 基础Widget总页面: "base_widget_page": (context) => BaseWidget(), "text_page": (context) => NewText(), // 学习 按钮 "button_page": (context) => NewButton(), // 学习图片组件及ICON 'image_page': (context) => NewImage(), // 学习单选开关和复选框 "switch_and_checkbox": (context) => NewSwitchAndCheckBox(), // 学习输入框及表单 "text_field_page": (context) => NewTextField(), // Form表单 "form_page": (context) => FormTestRoute(), /* 开始页面 布局类Widget 的学习: */ // 添加一个页面布局总页面 "row_column_page": (context) => RowAndColumnRoute(), // 学习纵向Row布局 "row_page": (context) => NewRow(), // 学习Flex弹性布局 "flex_page": (context) => NewFlex(), // 学习流式布局Wrap "wrap_page": (context) => NewWrap(), // 学习层叠布局Stack "stack_page": (context) => NewStack(), }, 复制代码
详细使用:
// 导入Material UI组件库 import 'package:flutter/material.dart'; import 'package:english_words/english_words.dart'; import 'package:flutter/cupertino.dart'; // 应用程序入口,runApp功能即启动Flutter应用,接收的参数为Widget参数 void main() => runApp(new MyApp()); // 继承一个无状态Widget组件,MyApp类代表Flutter应用 class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { // MaterialApp 设置应用名称、主题、语言、首页及路由列表等,其本身也是个Widget组件 return new MaterialApp( // 应用名称 title: 'Flutter Demos', // 应用主题 theme: new ThemeData( // 蓝色主题 primarySwatch: Colors.blue, ), // 使用命名路由管理route,首先注册路由表 routes: { "new_page": (context) => NewRoute(), // 使用新路由来学习 文本及样式 /* 开始 基础Widget 的学习: */ // 添加一个 基础Widget总页面: "base_widget_page": (context) => BaseWidget(), "text_page": (context) => NewText(), // 学习 按钮 "button_page": (context) => NewButton(), // 学习图片组件及ICON 'image_page': (context) => NewImage(), // 学习单选开关和复选框 "switch_and_checkbox": (context) => NewSwitchAndCheckBox(), // 学习输入框及表单 "text_field_page": (context) => NewTextField(), // Form表单 "form_page": (context) => FormTestRoute(), /* 开始页面 布局类Widget 的学习: */ // 添加一个页面布局总页面 "row_column_page": (context) => RowAndColumnRoute(), // 学习纵向Row布局 "row_page": (context) => NewRow(), // 学习Flex弹性布局 "flex_page": (context) => NewFlex(), // 学习流式布局Wrap "wrap_page": (context) => NewWrap(), // 学习层叠布局Stack "stack_page": (context) => NewStack(), }, // 应用首页路由 home: new MyHomePage(title: 'Flutter Demo Home Page'), ); } } // 即继承一个有状态Widget组件 class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key); final String title; @override // 对应该类的状态类 _MyHomePageState createState() => new _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { // “+” 次数记录 int _counter = 0; // 设置状态的自增函数 void _incrementCounter() { setState(() { _counter++; }); } @override // 构建UI界面的逻辑build方法 Widget build(BuildContext context) { return new Scaffold( appBar: new AppBar( title: new Text(widget.title), ), body: Wrap( spacing: 8.0, // 主轴(水平)方向间距 runSpacing: 4.0, // 纵轴(垂直)方向间距 alignment: WrapAlignment.center, //沿主轴方向居中 children: <Widget>[ new Text( 'You have pushed the button this many times:', ), new Text( '$_counter ', style: Theme.of(context).textTheme.display1, ), new Text('''基础显示'''), // 添加一个按钮组件,用于跳转新路由(新页面) // 跳转至新路由的按钮 FlatButton( child: Text('open new route'), textColor: Colors.blue, // 导航至新路由 onPressed: () { // 推至路由栈,路由管理Widget组件,通过栈来管理一个路由widget集合 即先进先出管理原则,这样好理解多了 // Navigator.push(context, // new MaterialPageRoute(builder: (context){ // return new NewRoute(); // // 通过路由名称也可以打开新的路由页 // }, // ) // ); Navigator.pushNamed(context, "new_page"); }), // 添加文本及样式路由按钮 RaisedButton( child: Text('基础Widgets'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, "base_widget_page"), ), RaisedButton( child: Text('布局学习'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'row_column_page'), ), // 通过english_words包随机显示一个英文单词 new RandomWordsWidget(), // 打印文字的组件 Echo( text: "大致学习过程", ) ], ), // 右下角的按钮 floatingActionButton: new FloatingActionButton( onPressed: _incrementCounter, tooltip: 'Increment', child: new Icon(Icons.add), ) // This trailing comma makes auto-formatting nicer for build methods. ); } } // 根据路由管理,尝试新的页面构建: class NewRoute extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('This is new route.')), body: Center(child: Text('nice route.'))); } } // 基础Weight学习 class BaseWidget extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('基础Widgets')), body: new Column( children: <Widget>[ FlatButton( child: Text('文本及样式', style: TextStyle( background: new Paint()..color = Colors.yellow, )), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, "text_page"), ), // 添加按钮路由按钮,该button有阴影效果 RaisedButton( child: Text('按钮'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, "button_page"), ), RaisedButton( child: Text('图片及ICON'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, "image_page"), ), RaisedButton( child: Text('单选开关及复选框'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, "switch_and_checkbox"), ), RaisedButton( child: Text("输入框及表单"), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'text_field_page'), ), RaisedButton( child: Text('表单Form'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'form_page'), ), ], ), ); } } // 文本及样式 class NewText extends StatelessWidget { @override Widget build(BuildContext context) { var scaffold = new Scaffold( appBar: AppBar( title: Text('文本及样式'), ), body: new Center( child: Column( // mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Text( "文本居中对齐." * 7, // 文本居中对齐 textAlign: TextAlign.center, ), Text( "文本显示的最大行数." * 4, // 文本显示的最大行数 maxLines: 1, // 指定若文本超过一行的戒断方式,ellipsis 表示截断为省略号 overflow: TextOverflow.ellipsis, ), Text( "字体大小的缩放因子,类似于大小调节", textScaleFactor: 1.5, ), Text("TextStyle用于指定文本显示的样式", style: TextStyle( color: Colors.blue, fontSize: 18, height: 1.2, fontFamily: "Courier", background: new Paint()..color = Colors.yellow, decoration: TextDecoration.underline, decorationStyle: TextDecorationStyle.dashed, )), // 对不同片段设置不同的样式,可以不断嵌套设置 Text.rich(TextSpan(children: [ TextSpan( text: 'Home ', ), TextSpan( text: "https://flutterchina.club", style: TextStyle( color: Colors.blue, ), // recognizer: _tapRecognizer, ), ])), // 设置默认样式,这种样式是可以继承的 DefaultTextStyle( style: TextStyle( color: Colors.red, fontSize: 20.0, ), textAlign: TextAlign.start, child: Column( crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[ Text("hello word!"), Text('多行测试'), // 尝试再次编辑文本样式,查看是否会覆盖默认样式 Text( '尝试再次编辑文本样式,查看是否会覆盖默认样式,结果:成功覆盖默认设置的样式', style: TextStyle( color: Colors.blue, fontSize: 14.0, ), ) ], ), ), ], )), ); return scaffold; } } // 按钮 class NewButton extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('按钮')), body: Center( child: Column( children: <Widget>[ RaisedButton( child: Text('RaiseButton'), onPressed: () {}, ), FlatButton( child: Text("FlatButton"), onPressed: () {}, ), OutlineButton( child: Text("OutlineButton"), onPressed: () {}, ), // 可点击的Icon IconButton( icon: Icon(Icons.thumb_up), onPressed: () {}, ), // 设置按钮样式,阴影风格真的不错。 RaisedButton( child: Text("按钮样式"), color: Colors.blue, highlightColor: Colors.blue[700], colorBrightness: Brightness.dark, splashColor: Colors.grey, shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(20.0)), onPressed: () {}, ), ], ), ), ); } } // 图片和Icon class NewImage extends StatelessWidget { // 预定义一组字体图标: @override Widget build(BuildContext context) { String icons = ""; // accessible: or 0xE914 or E914 icons += "\uE914"; // error: or 0xE000 or E000 icons += " \uE000"; // fingerprint: or 0xE90D or E90D icons += " \uE90D"; return new Scaffold( appBar: AppBar(title: Text('图片及ICON')), body: Center( child: Column( children: <Widget>[ // 本地图片组建 Image.asset( "images/avatar.png", width: 100.0, ), // 显示网络图片 Image.network( "https://avatars1.githubusercontent.com/u/20992063?s=460&v=4", width: 200.0, ), //简单设置图片属性 Image( image: NetworkImage( 'https://avatars1.githubusercontent.com/u/20992063?s=460&v=4'), width: 100, height: 100.0, color: Colors.blue, colorBlendMode: BlendMode.difference, // 图片空间小于显示空间,设置图片显示的重复规则 repeat: ImageRepeat.repeatY, ), // 字体图标的使用 Text( icons, style: TextStyle( fontFamily: "MaterialIcons", fontSize: 24.0, color: Colors.green), ), ], ), ), ); } } // 单选开关和复选框 class NewSwitchAndCheckBox extends StatefulWidget { @override _NewSwitchAndCheckBoxState createState() => new _NewSwitchAndCheckBoxState(); } class _NewSwitchAndCheckBoxState extends State<NewSwitchAndCheckBox> { bool _switchSelected = true; bool _checkboxSelected = true; @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('单选开关和复选框')), body: new Center( child: Column( children: <Widget>[ Switch( value: _switchSelected, //当前状态 onChanged: (value) { //重新构建页面 setState(() { _switchSelected = value; }); }, ), Checkbox( value: _checkboxSelected, // 选中时的颜色 activeColor: Colors.red, onChanged: (value) { setState(() { _checkboxSelected = value; }); }, ), ], )), ); } } // 简单输入 class NewTextField extends StatelessWidget { @override Widget build(BuildContext context) { // 定义一个controller,可以获取内容,也可以监听文本变化 TextEditingController _selectionControlle = new TextEditingController(); _selectionControlle.text = "Hello world"; _selectionControlle.selection = TextSelection( baseOffset: 2, extentOffset: _selectionControlle.text.length, ); return new Scaffold( appBar: AppBar(title: Text('输入框及表单')), body: new Center( child: new Column( children: <Widget>[ // 登陆输入框 TextField( autofocus: true, decoration: InputDecoration( labelText: "用户名", hintText: "用户名或邮箱", prefixIcon: Icon(Icons.person), ), // 可以通过onChanged获取输入的内容,也可以监听文本变化 // onChanged: (context){ // print(context); // }, // 比如通过controller获取输入的内容,监听文本变化,除了这两种功能,还可以设置默认值、选择文本 controller: _selectionControlle, ), TextField( decoration: InputDecoration( labelText: "密码", hintText: "您的登陆密码", prefixIcon: Icon(Icons.lock), ), obscureText: true, ), ], ), ), ); } } // 表单Form测试 class FormTestRoute extends StatefulWidget { @override _FormTestRouteState createState() => new _FormTestRouteState(); } class _FormTestRouteState extends State<FormTestRoute> { TextEditingController _unameController = new TextEditingController(); TextEditingController _pwdController = new TextEditingController(); GlobalKey _formKey = new GlobalKey<FormState>(); @override Widget build(BuildContext context) { // 此处不能使用PageScaffold 尝试普通布局 // return PageScaffold( // ...... // ); return new Scaffold( appBar: AppBar(title: Text('表单Form')), body: Padding( padding: const EdgeInsets.symmetric(vertical: 16.0, horizontal: 24.0), child: Form( key: _formKey, autovalidate: true, child: Column( children: <Widget>[ TextFormField( autofocus: true, controller: _unameController, decoration: InputDecoration( labelText: "用户名", hintText: '用户名或邮箱', icon: Icon(Icons.person), ), // 校验用户名 validator: (v) { return v.trim().length > 0 ? null : "用户名不能为空"; }, ), TextFormField( controller: _pwdController, decoration: InputDecoration( labelText: "密码", hintText: '您的登陆密码', icon: Icon(Icons.lock), ), obscureText: true, validator: (v) { return v.trim().length > 5 ? null : "密码不能少于6位"; }, ), // 登陆按钮 Padding( padding: const EdgeInsets.only(top: 28.0), child: Row( children: <Widget>[ Expanded( child: RaisedButton( padding: EdgeInsets.all(15.0), child: Text('登陆'), color: Theme.of(context).primaryColor, textColor: Colors.white, onPressed: () { if ((_formKey.currentState as FormState) .validate()) { //验证通过提交数据 } }, ), ), ], ), ), ], )), ), ); } } // 布局类Widgets 学习 class RowAndColumnRoute extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text("布局类Widgets 学习")), body: Column( children: <Widget>[ RaisedButton( child: Text('ROw纵向布局'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'row_page'), ), RaisedButton( child: Text('Flex弹性布局'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'flex_page'), ), RaisedButton( child: Text('Wrap流式布局'), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'wrap_page'), ), RaisedButton( child: Text("Stack层叠布局"), textColor: Colors.blue, onPressed: () => Navigator.pushNamed(context, 'stack_page'), ), ], )); } } // Row纵向布局 class NewRow extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('纵轴Row')), body: Column( //测试Row对齐方式,排除Column默认居中对齐的干扰 crossAxisAlignment: CrossAxisAlignment.start, // Widge子数组 children: <Widget>[ Row( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[Text('水平方向对齐方式.'), Text('现在是居中对齐.')], ), Row( mainAxisSize: MainAxisSize.min, mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Text(" hello world "), Text(" I am Jack "), ], ), Row( mainAxisAlignment: MainAxisAlignment.end, textDirection: TextDirection.rtl, children: <Widget>[ Text(" hello world "), Text(" I am Jack "), ], ), Row( crossAxisAlignment: CrossAxisAlignment.start, verticalDirection: VerticalDirection.up, children: <Widget>[ Text( " hello world ", style: TextStyle(fontSize: 30.0), ), Text(" I am Jack "), ], ), ], )); } } // 弹性布局Flex class NewFlex extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('Flex弹性布局')), body: new Column( children: <Widget>[ Flex( //Flex的两个子widget按1:2来占据水平空间 direction: Axis.horizontal, children: <Widget>[ Expanded( flex: 1, child: Container( height: 30.0, color: Colors.red, )), Expanded( flex: 2, child: Container( height: 30.0, color: Colors.green, )), ], ), Padding( padding: const EdgeInsets.only(top: 20), child: SizedBox( height: 100.0, child: Flex( //Flex的三个子widget,在 垂直 方向按2:1:1来占用100像素的空间 direction: Axis.vertical, children: <Widget>[ Expanded( flex: 1, child: Container( height: 30.0, color: Colors.red, ), ), // 一个Flex的简单包装 Spacer( flex: 1, ), Expanded( flex: 1, child: Container( height: 30.0, color: Colors.green, ), ), ], ), ), ), ], )); } } // 流式布局Wrap、Flow class NewWrap extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('流式布局Wrap')), body: Wrap( // 主轴水平方向间距 spacing: 8.0, // 纵轴垂直方向间距 runSpacing: 4.0, // 沿主轴方向居中 alignment: WrapAlignment.center, children: <Widget>[ new Chip( avatar: new CircleAvatar( backgroundColor: Colors.blue, child: Text('A')), label: new Text('Hamilton')), new Chip( avatar: new CircleAvatar( backgroundColor: Colors.blue, child: Text('M')), label: new Text('Lafayette'), ), new Chip( avatar: new CircleAvatar( backgroundColor: Colors.blue, child: Text('H')), label: new Text('Mulligan'), ), new Chip( avatar: new CircleAvatar( backgroundColor: Colors.blue, child: Text('J')), label: new Text('Laurens'), ), ], ), ); } } // 层叠布局 Stack、Positioned class NewStack extends StatelessWidget { @override Widget build(BuildContext context) { return new Scaffold( appBar: AppBar(title: Text('层叠布局Stack')), body: new ConstrainedBox( constraints: BoxConstraints.expand(), child: Stack( // 指定未定位或部分定位widget的对齐方式 alignment: Alignment.center, children: <Widget>[ Container( child: Text('Hello world', style: TextStyle( color: Colors.white, )), color: Colors.red, ), Positioned( left: 18.0, child: Text("I'm Jack"), ), Positioned( top: 18.0, child: Text("Your Friend"), ), ], )), ); } } class CuoertinoTestRoute extends StatelessWidget { @override Widget build(BuildContext context) { return CupertinoPageScaffold( navigationBar: CupertinoNavigationBar( middle: Text("Cupertino Demo"), ), child: Center( child: CupertinoButton( color: CupertinoColors.activeBlue, child: Text("Press"), onPressed: () {}, ), ), ); } } class RandomWordsWidget extends StatelessWidget { @override Widget build(BuildContext context) { final wordPair = new WordPair.random(); return new Padding( padding: const EdgeInsets.all(8.0), child: new Text(wordPair.toString())); } } class Echo extends StatelessWidget { const Echo({ Key key, @required this.text, this.backgroundColor: Colors.grey, }) : super(key: key); final String text; final Color backgroundColor; @override Widget build(BuildContext context) { return Center( child: Container( color: backgroundColor, child: Text(text), )); } } 复制代码
以下是Demo的总页面和分页面及效果图:
Summary
逐渐构建,思考,记录完善学习过程,希望后续能够将整个学习的过程整合为一个app,这样既能学习到知识,又能够记录下来。
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具体数学(英文版第2版)
[美] Ronald L. Graham、Donald E. Knuth、Oren Patashnik / 机械工业出版社 / 2002-8 / 49.00元
This book introduces the mathematics that supports advanced computer Programming and the analysis of algorithms. The primary aim of its well-known authors is to provide a solid and relevant base of ma......一起来看看 《具体数学(英文版第2版)》 这本书的介绍吧!