Flutter开发之图片选择器

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: '图片选择器示例',
      home: MyHomePage(),
    );
  }
}
 
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);
 
  @override
  _MyHomePageState createState() => _MyHomePageState();
}
 
class _MyHomePageState extends State<MyHomePage> {
  File _image;
  final ImagePicker _picker = ImagePicker();
 
  // 从相册选择图片
  Future<void> _pickImageFromGallery() async {
    final XFile image = await _picker.pickImage(
      source: ImageSource.gallery,
    );
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }
 
  // 从相机拍照选择图片
  Future<void> _pickImageFromCamera() async {
    final XFile image = await _picker.pickImage(
      source: ImageSource.camera,
    );
    if (image != null) {
      setState(() {
        _image = File(image.path);
      });
    }
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('图片选择器示例'),
      ),
      body: Center(
        child: _image == null
            ? Text('没有选择图片')
            : Image.file(_image),
      ),
      floatingActionButton: Column(
        crossAxisAlignment: CrossAxisAlignment.end,
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 5.0),
            child: FloatingActionButton(
              onPressed: _pickImageFromGallery,
              tooltip: '选择图片',
              child: Icon(Icons.photo_library),
            ),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 5.0),
            child: FloatingActionButton(
              onPressed: _pickImageFromCamera,
              tooltip: '拍照',
              child: Icon(Icons.camera_alt),
            ),
          ),
        ],
      ),
    );
  }
}

这段代码使用了image_picker插件，实现了从相册和相机中选择图片的功能。用户可以通过点击底部的浮动按钮来选择图片，选择的图片会显示在屏幕中央。这是一个非常基础的图片选择器实现，适合作为学习Flutter的参考。