Flutter第四期 - 佈局控件瞭解一下

寫了幾天的基礎控件，大家對於flutter有了一個初步的認識，但是還是會記不住，不過我相信寫出來的代碼應該很舒服了，起碼我是這麼感覺的，代碼廢的地方几乎沒有，一氣呵成~接下來繼續瞭解佈局這塊，這塊學完，感覺就可以開始敲APP了，佈局是APP中的大項，其他的業務網絡什麼的都可以有現成不變的框架去套，只有佈局是跟著業務走的，所以這篇你只要一遍又一遍的去敲，熟練後你發現你代碼速度就上來了~嗯~

1.線性佈局Row和Column：Bootstrap記得吧 大學都玩過吧，跟這個很像的，根據水平和垂直方向來佈局，其實早就應該這麼玩了，當然適配就交給google了~哈哈~

import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
//Stateless widgets 是不可變的, 這意味著它們的屬性不能改變 - 所有的值都是最終的.
//Stateful widgets 持有的狀態可能在widget生命週期中發生變化. 實現一個 stateful widget 至少需要兩個類:
class MyApp extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
 // TODO: implement build
 return new MaterialApp(
 title: "線性佈局Row和Column",
 home: new Scaffold(
 appBar: new AppBar(
 title: new Text("線性佈局Row和Column"),
 ),
 body: new Center(
 child: new FormTestRoute(),
 ),
 ),
 );
 }
}
class FormTestRoute extends StatefulWidget {
 @override
 _FormTestRouteState createState() => new _FormTestRouteState();
}
class _FormTestRouteState extends State {
 @override
 Widget build(BuildContext context) {
 return Scaffold(
// title: "Form Test",
 body: Container(
 color: Colors.grey,
 child: Padding(
 padding: const EdgeInsets.all(10.0),
 child: Column(
 crossAxisAlignment: CrossAxisAlignment.start,
 mainAxisSize: MainAxisSize.max,
 children: [
 Container(
 color: Colors.blue,
 child: Column(
 mainAxisSize: MainAxisSize.max,
 children: [
 new Text("hi yun~"),
 new Text("I am lx"),
 ],
 ),
 ),
 Expanded(
 child: Container(
 color: Colors.green,
 child: Column(
 mainAxisAlignment: MainAxisAlignment.center,
 children: [
 new Text("hi yun~"),
 new Text("I am lx"),
 ],
 ),
 ),
 ),
 Row(
 mainAxisAlignment: MainAxisAlignment.center,
 children: [
 Text(" hello world "),
 Text(" I am Jack "),
 ],
 ),
 Row(
 mainAxisSize: MainAxisSize.min,
 mainAxisAlignment: MainAxisAlignment.center,
 children: [
 Text(" hello world "),
 Text(" I am Jack "),
 ],
 ),
 Row(
 mainAxisAlignment: MainAxisAlignment.end,
 textDirection: TextDirection.rtl,
 children: [
 Text(" hello world "),
 Text(" I am Jack "),
 ],
 ),
 Row(
 crossAxisAlignment: CrossAxisAlignment.start,
 verticalDirection: VerticalDirection.up,
 children: [
 Text(" hello world ", style: TextStyle(fontSize: 30.0),),
 Text(" I am Jack "),
 ],
 ),
 ],
 ),
 ),
 ),
 );
 }
}

2.彈性佈局Flex：這是大家熟悉的權重布方式

import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
//Stateless widgets 是不可變的, 這意味著它們的屬性不能改變 - 所有的值都是最終的.
//Stateful widgets 持有的狀態可能在widget生命週期中發生變化. 實現一個 stateful widget 至少需要兩個類:
class MyApp extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
 // TODO: implement build
 return new MaterialApp(
 title: "彈性佈局Flex",
 home: new Scaffold(
 appBar: new AppBar(
 title: new Text("彈性佈局Flex"),
 ),
 body: new Center(
 child: new FormTestRoute(),
 ),
 ),
 );
 }
}
class FormTestRoute extends StatefulWidget {
 @override
 _FormTestRouteState createState() => new _FormTestRouteState();
}
class _FormTestRouteState extends State {
 @override
 Widget build(BuildContext context) {
 return Column(
 children: [
 Flex(
 direction: Axis.horizontal,
 children: [
 Expanded(
 flex: 1,
 child: Container(
 height: 30.0,
 color: Colors.red,
 ),
 ),
 Expanded(
 flex: 2,
 child: Container(
 height: 30.0,
 color: Colors.blue,
 ),
 ),
 ],
 ),
 Padding(
 padding: const EdgeInsets.only(top: 40.0),
 child: SizedBox(
 height: 100.0,
 child: Flex(
 direction: Axis.vertical,
 children: [
 Expanded(
 flex: 2,
 child: Container(
 height: 30.0,
 color: Colors.red,
 ),
 ),
 Spacer(
 flex: 1,
 ),
 Expanded(
 flex: 1,
 child: Container(
 height: 30.0,
 color: Colors.blue,
 ),
 ),
 ],
 ),
 ),
 ),
 ],
 );
 }
}

3.流式佈局：之前的標籤flowlayout有印象吧 嗯~

import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
//Stateless widgets 是不可變的, 這意味著它們的屬性不能改變 - 所有的值都是最終的.
//Stateful widgets 持有的狀態可能在widget生命週期中發生變化. 實現一個 stateful widget 至少需要兩個類:
class MyApp extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
 // TODO: implement build
 return new MaterialApp(
 title: "流式佈局",
 home: new Scaffold(
 appBar: new AppBar(
 title: new Text("流式佈局"),
 ),
 body: new Center(
 child: new FormTestRoute(),
 ),
 ),
 );
 }
}
class FormTestRoute extends StatefulWidget {
 @override
 _FormTestRouteState createState() => new _FormTestRouteState();
}
class _FormTestRouteState extends State {
 @override
 Widget build(BuildContext context) {
 return Column(
 children: [
 Wrap(
 spacing: 2.0,
 runSpacing: 4.0,
 alignment: WrapAlignment.start,
 children: [
 new Chip(
 label: new Text("hi yun1"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.blue,
 child: Text("A"),
 ),
 ),
 new Chip(
 label: new Text("yun1"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.blue,
 child: Text("Y1"),
 ),
 ),
 new Chip(
 label: new Text("hi yun2"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.blueAccent,
 child: Text("Y2"),
 ),
 ),
 new Chip(
 label: new Text("yun3"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.lightBlue,
 child: Text("Y3"),
 ),
 ),
 new Chip(
 label: new Text("hi yun4"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.lightBlueAccent,
 child: Text("Y4"),
 ),
 ),
 new Chip(
 label: new Text("hi yun4"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.lightBlueAccent,
 child: Text("Y4"),
 ),
 ),
 new Chip(
 label: new Text("hi yun4"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.lightBlueAccent,
 child: Text("Y4"),
 ),
 ),
 new Chip(
 label: new Text("hi yun4"),
 avatar: new CircleAvatar(
 backgroundColor: Colors.lightBlueAccent,
 child: Text("Y4"),
 ),
 ),
 ],
 ),
 ],
 );
 }
}
 

4.層疊佈局：這個就厲害了，以後會用的多，相當於Framelayout

import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
//Stateless widgets 是不可變的, 這意味著它們的屬性不能改變 - 所有的值都是最終的.
//Stateful widgets 持有的狀態可能在widget生命週期中發生變化. 實現一個 stateful widget 至少需要兩個類:
class MyApp extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
 // TODO: implement build
 return new MaterialApp(
 title: "層疊佈局",
 home: new Scaffold(
 appBar: new AppBar(
 title: new Text("層疊佈局"),
 ),
 body: new Center(
// child: new FormTestRoute1(),
 child: new FormTestRoute2(),
 ),
 ),
 );
 }
}
class FormTestRoute1 extends StatefulWidget {
 @override
 _FormTestRouteState1 createState() => new _FormTestRouteState1();
}
class FormTestRoute2 extends StatefulWidget {
 @override
 _FormTestRouteState2 createState() => new _FormTestRouteState2();
}
class _FormTestRouteState1 extends State {
 @override
 Widget build(BuildContext context) {
 return ConstrainedBox(
 constraints: BoxConstraints.expand(),
 child: Stack(
 alignment: Alignment.center,
 children: [
 Container(
 child: Text(
 "hi yun1",
 style: TextStyle(color: Colors.white),
 ),
 color: Colors.red,
 ),
 Positioned(
 left: 18.0,
 child: Text("hi yun2"),
 ),
 Positioned(
 top: 18.0,
 child: Text("hi yun3"),
 ),
 ],
 ),
 );
 }
}
class _FormTestRouteState2 extends State {
 @override
 Widget build(BuildContext context) {
 return ConstrainedBox(
 constraints: BoxConstraints.expand(),
 child: Stack(
 alignment: Alignment.center,
 fit: StackFit.expand, // 未定位widget佔滿Stack整個空間
 children: [
 Positioned(
 left: 18.0,
 child: Text("hi yun2"),
 ),
 Container(
 child: Text(
 "hi yun1",
 style: TextStyle(color: Colors.white),
 ),
 color: Colors.red,
 ),
 Positioned(
 top: 18.0,
 child: Text("hi yun3"),
 ),
 ],
 ),
 );
 }
}

總結：看上去其實不難，但是我發現在佈局的過程遇到的都是綜合的情況，所以還是要找一個比較複雜的佈局去試試，敲一敲，這樣你才會用的熟練~下期見~