import 'package:flutter/material.dart';

//导入拍照插件

import 'package:image_picker/image_picker.dart';

//导入文件操作库

import 'dart:io';

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

class MyApp extends StatelessWidget {

// This widget is the root of your application.

@override

Widget build(BuildContext context) {

//flutter项目必须返回MaterialApp,flutter项目从MaterialApp组件开始

return MaterialApp(

title: 'Flutter Demo',

theme: ThemeData(

primarySwatch: Colors.red,

),

home: MyHomePage(title: '手机相册'),

);

}

}

class MyHomePage extends StatefulWidget {

MyHomePage({Key key, this.title}) : super(key: key);

final String title;

@override

_MyHomePageState createState() => _MyHomePageState();

}

class _MyHomePageState extends State {

//用户选择的照片

File _image;

Future choosePic(ImageSource source) async { //参数类型为ImageSource

var image = await ImagePicker.pickImage(source: source);

setState(() {

//将用户照片存储到_image

_image=image;

});

}

@override

Widget build(BuildContext context) {

return Scaffold(

//appBar订制导航条

appBar: renderAppBar(),

body: renderBody(),

floatingActionButton:renderFloatingActionBar(),

);

}

//渲染头部的Appbar

Widget renderAppBar(){

return AppBar(

title:Text(widget.title),

centerTitle: true,

);

}

//渲染页面主体区域

Widget renderBody(){

if(_image==null){

return Center(child:Text("请选择照片！"),) ;

}

return Image.file(_image,fit: BoxFit.cover,width: double.infinity,height: double.infinity,);

}

//渲染底部浮动按钮

Widget renderFloatingActionBar(){

return ButtonBar(

//设置对齐方式

alignment: MainAxisAlignment.spaceAround,

children: [

//第一个浮动按钮

FloatingActionButton(

onPressed: (){

choosePic(ImageSource.camera);

},

tooltip: 'photo_camera',

child: Icon(Icons.photo_camera), //相机拍照

),

//第二个浮动按钮

FloatingActionButton(

onPressed: (){

choosePic(ImageSource.gallery);

},

tooltip: 'photo_libarary',

child: Icon(Icons.photo_library), //选择相册照片

)

],

);

}

}