Flutter 页面布局 Stack层叠组件

Stack 表示堆的意思，我们可以用 Stack 或者 Stack 结合 Align 或者 Stack 结合 Positiond 来实现页面的定位布局

属性	说明
alignment	配置所有子元素的显示位置
children	子组件

Stack 组件中结合 Positioned 组件可以控制每个子元素的显示位置

属性	说明
top	子元素距离顶部的距离
bottom	子元素距离底部的距离
left	子元素距离左侧距离
right	子元素距离右侧距离
child	子组件

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
        home: Scaffold(
      appBar: AppBar(title: Text('FlutterDemo')),
      body: LayoutDemo(),
    ));
  }
}

class LayoutDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Center(
      child:  Container(
            height: 400,
            width: 300,
            color: Colors.red,
            child: Stack(
              // alignment: Alignment.center,
              children: <Widget>[
                Positioned(
                //  left: 10,
                  child: Icon(Icons.home,size: 40,color: Colors.white),
                ),
                Positioned(
                 bottom: 0,
                 left: 100,
                  child: Icon(Icons.search,size: 30,color: Colors.white),
                ),
                Positioned(
                  right: 0,
                  child: Icon(Icons.settings_applications,size: 30,color: Colors.white),
                )
              ],
            ),
      ),
    );
  }
}

Stack 组件中结合 Align 组件可以控制每个子元素的显示位置

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
        home: Scaffold(
      appBar: AppBar(title: Text('FlutterDemo')),
      body: LayoutDemo(),
    ));
  }
}

class LayoutDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Center(
      child:  Container(
            height: 400,
            width: 300,
            color: Colors.red,
            child: Stack(
              // alignment: Alignment.center,
              children: <Widget>[
                Align(
                  alignment: Alignment(1,-0.2),
                  child: Icon(Icons.home,size: 40,color: Colors.white),
                ),
                Align(
                  alignment: Alignment.center,
                  child: Icon(Icons.search,size: 30,color: Colors.white),
                ),
                Align(
                  alignment: Alignment.bottomRight,
                  child: Icon(Icons.settings_applications,size: 30,color: Colors.white),
                )
              ],
            ),
      ),
    );
  }
}

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
        home: Scaffold(
      appBar: AppBar(title: Text('FlutterDemo')),
      body: LayoutDemo(),
    ));
  }
}

class LayoutDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Center(
      child: Stack(
        alignment: Alignment.topLeft,
        children: <Widget>[
          Container(
            height: 400,
            width: 300,
            color: Colors.red,
          ),
          Text('我是一个文本',style: TextStyle(
            fontSize: 40,
            color: Colors.white
          ))
        ],
      ),
    );
  }
}