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，代碼廢的地方幾乎沒有，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，只有佈局是跟着業務走的，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, 這意味着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<FormTestRoute> {
@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: <Widget>[
Container(
color: Colors.blue,
child: Column(
mainAxisSize: MainAxisSize.max,
children: <Widget>[
new Text("hi yun~"),
new Text("I am lx"),
],
),
),
Expanded(
child: Container(
color: Colors.green,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text("hi yun~"),
new Text("I am lx"),
],
),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(" hello world "),
Text(" I am Jack "),
],
),
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 "),
],
),
],
),
),
),
);
}
} 
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, 這意味着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<FormTestRoute> {
@override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
Flex(
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.blue,
),
),
],
),
Padding(
padding: const EdgeInsets.only(top: 40.0),
child: SizedBox(
height: 100.0,
child: Flex(
direction: Axis.vertical,
children: <Widget>[
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, 這意味着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<FormTestRoute> {
@override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
Wrap(
spacing: 2.0,
runSpacing: 4.0,
alignment: WrapAlignment.start,
children: <Widget>[
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, 這意味着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<FormTestRoute1> {
@override
Widget build(BuildContext context) {
return ConstrainedBox(
constraints: BoxConstraints.expand(),
child: Stack(
alignment: Alignment.center,
children: <Widget>[
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<FormTestRoute2> {
@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: <Widget>[
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，這樣你纔會用的熟練~下期見~
