插件地址：https://pub.dev/packages/image_picker

1. 添加插件
   
2. 添加配置

android无需配置开箱即用，ios还需要配置info.plist

<key>NSPhotoLibraryUsageDescription</key> <string>应用需要访问相册读取文件</string> 
<key>NSCameraUsageDescription</key> <string>应用需要访问相机拍照</string> 
<key>NSMicrophoneUsageDescription</key> <string>应用需要访问麦克风录制视频</string>

3. 核心代码

import 'package:image_picker/image_picker.dart';final ImagePicker picker = ImagePicker();
// 从相册选择相机
final XFile? image = await picker.pickImage(source: ImageSource.gallery);
// 拍照
final XFile? photo = await picker.pickImage(source: ImageSource.camera);
// 从相册选择视频
final XFile? galleryVideo =await picker.pickVideo(source: ImageSource.gallery);
// 录制视频
final XFile? cameraVideo = await picker.pickVideo(source: ImageSource.camera);

4. 完整代码

import 'dart:io';import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
// 本地视频播放的逻辑
import 'package:video_player/video_player.dart';
import 'package:chewie/chewie.dart';class ImagePickerDemo extends StatefulWidget {const ImagePickerDemo({super.key});@overrideState<ImagePickerDemo> createState() => _ImagePickerDemoState();
}class _ImagePickerDemoState extends State<ImagePickerDemo> {final ImagePicker _imagePicker  = ImagePicker();XFile? _pickerImage;XFile? _pickerVideo;// 配置加载本地视频late VideoPlayerController _videoPlayerController;late ChewieController _chewieController;// 拍照void _imagePickerCamera() async {final XFile? image = await _imagePicker.pickImage(source: ImageSource.camera,// 可以不设置，设置上可以避免数据太大maxHeight: 800,maxWidth: 800);if (image != null) {print(image.path);setState(() {_pickerVideo = null;_pickerImage = image;});}}// 相册选择图片void _imagePickerGallery() async {final XFile? image = await _imagePicker.pickImage(source: ImageSource.gallery,// 可以不设置，设置上可以避免数据太大maxHeight: 800,maxWidth: 800);if (image != null) {print(image.path);setState(() {_pickerVideo = null;_pickerImage = image;});} }// 视频-选择相机录制void _videoPickerCamera() async {final XFile? video = await _imagePicker.pickVideo(source: ImageSource.camera);if (video != null) {print(video.path);await _initVideo(File(video.path));setState(() {_pickerImage = null;_pickerVideo = video;});}}// 视频-选择相册void _videoPickerGallery() async {final XFile? video = await _imagePicker.pickVideo(source: ImageSource.gallery);if (video != null) {print(video.path);await _initVideo(File(video.path));setState(() {_pickerImage = null;_pickerVideo = video;});}}// 显示图片或者显示视频Widget _showImageOrVideoWidget() {if (_pickerImage != null) {return Image.file(File(_pickerImage!.path));} else if (_pickerVideo != null) {return AspectRatio(aspectRatio: _videoPlayerController.value.aspectRatio,child: Chewie(controller: _chewieController));} else {return Text("请选择图片或者视频");}}// 初始化播放器--用于播放本地视频Future _initVideo(File fileDir) async {_videoPlayerController = VideoPlayerController.file(fileDir);await _videoPlayerController.initialize();_chewieController = ChewieController(videoPlayerController: _videoPlayerController,aspectRatio: _videoPlayerController.value.aspectRatio,autoPlay: true,looping: false);}@overridevoid dispose() {try {_videoPlayerController.dispose();_chewieController.dispose();} catch (e) {print(e);}super.dispose();}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text("图片选择器"),),body: ListView(padding: EdgeInsets.all(10),children: [Center(child: ElevatedButton(onPressed: _imagePickerGallery, child: Text("图片-选择相册"))),Center(child: ElevatedButton(onPressed: _imagePickerCamera, child: Text("图片-选择相机"))),Center(child: ElevatedButton(onPressed: _videoPickerGallery, child: Text("视频-选择相册"))),Center(child: ElevatedButton(onPressed: _videoPickerCamera, child: Text("视频-选择相机"))),SizedBox(height: 20),// 展示图片或者视频_showImageOrVideoWidget()],),);}
}

5. 效果图
   
6. 上传文件（未测试，先记录）

  _uploadFile(String imagePath) async {var formData = FormData.fromMap({'name': 'wendux', 'age': 25, 'file': await MultipartFile.fromFile(imagePath, filename: 'aaa.png')}); var response = await Dio().post('https://xxx/imgupload', data: formData);print(response); }
}