挑选系统的相册，调用相机的功能，需要用到官网插件image_picker
【运行报错】
ERROR:D8: Cannot fit requested classes in a single dex file (# methods: 68998 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
【解决】
启动MultiDex
【怎么启动】
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// ignore_for_file: public_member_api_docs
import 'dart:async';
import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:video_player/video_player.dart';
class MyImagePicker extends StatelessWidget {
const MyImagePicker({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Image Picker Demo',
home: MyHomePage(title: 'Image Picker Example'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, this.title}) : super(key: key);
final String? title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<XFile>? _imageFileList;
void _setImageFileListFromFile(XFile? value) {
_imageFileList = value == null ? null : <XFile>[value];
}
dynamic _pickImageError;
bool isVideo = false;
VideoPlayerController? _controller;
VideoPlayerController? _toBeDisposed;
String? _retrieveDataError;
final ImagePicker _picker = ImagePicker();
final TextEditingController maxWidthController = TextEditingController();
final TextEditingController maxHeightController = TextEditingController();
final TextEditingController qualityController = TextEditingController();
//取得视频的资源之后进行视频的播放
Future<void> _playVideo(XFile? file) async {
if (file != null && mounted) {
await _disposeVideoController();
late VideoPlayerController controller;
if (kIsWeb) {
controller = VideoPlayerController.network(file.path);
} else {
controller = VideoPlayerController.file(File(file.path));
}
_controller = controller;
// In web, most browsers won't honor a programmatic call to .play
// if the video has a sound track (and is not muted).
// Mute the video so it auto-plays in web!
// This is not needed if the call to .play is the result of user
// interaction (clicking on a "play" button, for example).
//控制视频的播放
const double volume = kIsWeb ? 0.0 : 1.0;
await controller.setVolume(volume);
await controller.initialize();
await controller.setLooping(true);
await controller.play();
setState(() {});
}
}
/**点击右侧浮游按钮的处理方法
* */
Future<void> _onImageButtonPressed(ImageSource source,
{BuildContext? context, bool isMultiImage = false}) async {
if (_controller != null) {
await _controller!.setVolume(0.0);
}
//处理Video
if (isVideo) {
//调用插件方法
final XFile? file = await _picker.pickVideo(
source: source, maxDuration: const Duration(seconds: 10));
await _playVideo(file);
}
//处理多张照片
else if (isMultiImage) {
await _displayPickImageDialog(context!,
(double? maxWidth, double? maxHeight, int? quality) async {
try {
//调用插件方法
final List<XFile>? pickedFileList = await _picker.pickMultiImage(
maxWidth: maxWidth,
maxHeight: maxHeight,
imageQuality: quality,
);
setState(() {
_imageFileList = pickedFileList;
});
} catch (e) {
setState(() {
_pickImageError = e;
});
}
});
}
//处理一张照片
else {
await _displayPickImageDialog(context!,
(double? maxWidth, double? maxHeight, int? quality) async {
try {
final XFile? pickedFile = await _picker.pickImage(
source: source,
maxWidth: maxWidth,
maxHeight: maxHeight,
imageQuality: quality,
);
setState(() {
_setImageFileListFromFile(pickedFile);
});
} catch (e) {
setState(() {
_pickImageError = e;
});
}
});
}
}
@override
void deactivate() {
if (_controller != null) {
_controller!.setVolume(0.0);
_controller!.pause();
}
super.deactivate();
}
@override
void dispose() {
_disposeVideoController();
maxWidthController.dispose();
maxHeightController.dispose();
qualityController.dispose();
super.dispose();
}
Future<void> _disposeVideoController() async {
if (_toBeDisposed != null) {
await _toBeDisposed!.dispose();
}
_toBeDisposed = _controller;
_controller = null;
}
//中间的提示文字
Widget _previewVideo() {
final Text? retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_controller == null) {
return const Text(
'You have not yet picked a video',
textAlign: TextAlign.center,
);
}
return Padding(
padding: const EdgeInsets.all(10.0),
child: AspectRatioVideo(_controller),
);
}
//中间的提示文字
Widget _previewImages() {
final Text? retrieveError = _getRetrieveErrorWidget();
if (retrieveError != null) {
return retrieveError;
}
if (_imageFileList != null) {
return Semantics(
label: 'image_picker_example_picked_images',
child: ListView.builder(
key: UniqueKey(),
itemBuilder: (BuildContext context, int index) {
// Why network for web?
// See https://pub.dev/packages/image_picker#getting-ready-for-the-web-platform
return Semantics(
label: 'image_picker_example_picked_image',
child: kIsWeb
? Image.network(_imageFileList![index].path)
: Image.file(File(_imageFileList![index].path)),
);
},
itemCount: _imageFileList!.length,
),
);
} else if (_pickImageError != null) {
return Text(
'Pick image error: $_pickImageError',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
//对中间提示文字进行了一次封装
Widget _handlePreview() {
if (isVideo) {
return _previewVideo();
} else {
return _previewImages();
}
}
Future<void> retrieveLostData() async {
final LostDataResponse response = await _picker.retrieveLostData();
if (response.isEmpty) {
return;
}
if (response.file != null) {
//如果是video
if (response.type == RetrieveType.video) {
isVideo = true;
await _playVideo(response.file);
}
//是图片
else {
isVideo = false;
setState(() {
if (response.files == null) {
_setImageFileListFromFile(response.file);
} else {
_imageFileList = response.files;
}
});
}
} else {
_retrieveDataError = response.exception!.code;
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
// appBar: AppBar(
// title: Text(widget.title!),
// ),
body: Center(
child: !kIsWeb && defaultTargetPlatform == TargetPlatform.android
? FutureBuilder<void>(
future: retrieveLostData(),//以后呈现的widget?
builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
case ConnectionState.done:
return _handlePreview();
default:
if (snapshot.hasError) {
return Text(
'Pick image/video error: ${snapshot.error}}',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
},
)
: _handlePreview(),
),
/**右侧的浮游按钮*/
floatingActionButton: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Semantics(//给UI加上语义，对一些语法分析器或者搜索引擎有帮助
label: 'image_picker_example_from_gallery',
child: FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.gallery, context: context);
},
heroTag: 'image0',
tooltip: 'Pick Image from gallery',
child: const Icon(Icons.photo),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(
ImageSource.gallery,
context: context,
isMultiImage: true,
);
},
heroTag: 'image1',
tooltip: 'Pick Multiple Image from gallery',
child: const Icon(Icons.photo_library),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
onPressed: () {
isVideo = false;
_onImageButtonPressed(ImageSource.camera, context: context);
},
heroTag: 'image2',
tooltip: 'Take a Photo',
child: const Icon(Icons.camera_alt),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.gallery);
},
heroTag: 'video0',
tooltip: 'Pick Video from gallery',
child: const Icon(Icons.video_library),
),
),
Padding(
padding: const EdgeInsets.only(top: 16.0),
child: FloatingActionButton(
backgroundColor: Colors.red,
onPressed: () {
isVideo = true;
_onImageButtonPressed(ImageSource.camera);
},
heroTag: 'video1',
tooltip: 'Take a Video',
child: const Icon(Icons.videocam),
),
),
],
),
);
}
Text? _getRetrieveErrorWidget() {
if (_retrieveDataError != null) {
final Text result = Text(_retrieveDataError!);
_retrieveDataError = null;
return result;
}
return null;
}
Future<void> _displayPickImageDialog(
BuildContext context, OnPickImageCallback onPick) async {
return showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Add optional parameters'),
content: Column(
children: <Widget>[
TextField(
controller: maxWidthController,//该变量存储输入内容的值
keyboardType:
const TextInputType.numberWithOptions(decimal: true),
decoration: const InputDecoration(
hintText: 'Enter maxWidth if desired'),
),
TextField(
controller: maxHeightController,
keyboardType:
const TextInputType.numberWithOptions(decimal: true),
decoration: const InputDecoration(
hintText: 'Enter maxHeight if desired'),
),
TextField(
controller: qualityController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
hintText: 'Enter quality if desired'),
),
],
),
actions: <Widget>[
TextButton(
child: const Text('CANCEL'),
onPressed: () {
Navigator.of(context).pop();
},
),
TextButton(
child: const Text('PICK'),
onPressed: () {
final double? width = maxWidthController.text.isNotEmpty
? double.parse(maxWidthController.text)
: null;
final double? height = maxHeightController.text.isNotEmpty
? double.parse(maxHeightController.text)
: null;
final int? quality = qualityController.text.isNotEmpty
? int.parse(qualityController.text)
: null;
onPick(width, height, quality);
Navigator.of(context).pop();
}),
],
);
});
}
}
typedef OnPickImageCallback = void Function(
double? maxWidth, double? maxHeight, int? quality);
class AspectRatioVideo extends StatefulWidget {
const AspectRatioVideo(this.controller, {Key? key}) : super(key: key);
final VideoPlayerController? controller;
@override
AspectRatioVideoState createState() => AspectRatioVideoState();
}
class AspectRatioVideoState extends State<AspectRatioVideo> {
VideoPlayerController? get controller => widget.controller;
bool initialized = false;
void _onVideoControllerUpdate() {
if (!mounted) {
return;
}
if (initialized != controller!.value.isInitialized) {
initialized = controller!.value.isInitialized;
setState(() {});
}
}
@override
void initState() {
super.initState();
controller!.addListener(_onVideoControllerUpdate);
}
@override
void dispose() {
controller!.removeListener(_onVideoControllerUpdate);
super.dispose();
}
@override
Widget build(BuildContext context) {
if (initialized) {
return Center(
child: AspectRatio(
aspectRatio: controller!.value.aspectRatio,
child: VideoPlayer(controller!),
),
);
} else {
return Container();
}
}
}
主页面
挑选一张照片
正在播放视频
