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简单学习一下几个比较好用的文件读取库
video_player
简介 用于视频播放
官方文档 https://pub-web.flutter-io.cn/packages/video_player
安装
flutter pub add video_player加载网络视频
class _MyHomePageState extends StateMyHomePage {// 控制器late…前言
简单学习一下几个比较好用的文件读取库
video_player
简介 用于视频播放
官方文档 https://pub-web.flutter-io.cn/packages/video_player
安装
flutter pub add video_player加载网络视频
class _MyHomePageState extends StateMyHomePage {// 控制器late VideoPlayerController _controller;// 初始化overridevoid initState() {super.initState();// 加载网络视频_controller VideoPlayerController.networkUrl(Uri.parse(https://www.tujuyun.com/pixabay/video/VideoBig/1024927/4006.mp4))..initialize().then((_) {setState(() {});});}overridevoid dispose() {super.dispose();_controller.dispose();}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: _controller.value.isInitialized // 判断是否已经加载完成? AspectRatio(// 设置视频播放的宽高比aspectRatio: _controller.value.aspectRatio,child: VideoPlayer(_controller),): Container(),),floatingActionButton: FloatingActionButton(onPressed: () {setState(() {_controller.value.isPlaying // 判断是否是在播放中? _controller.pause() //暂停: _controller.play(); // 播放});},child: Icon(_controller.value.isPlaying ? Icons.pause : Icons.play_arrow,),),);}
}加载本地视频 _controller VideoPlayerController.asset(lib/assets/video/3998.mp4)..initialize().then((_) {setState(() {});});设置倍速和进度条
Center(child: _controller.value.isInitialized // 判断是否已经加载完成? AspectRatio(// 设置视频播放的宽高比aspectRatio: _controller.value.aspectRatio,child: Stack(alignment: Alignment.bottomCenter,children: Widget[// 视频播放器VideoPlayer(_controller),// 设置倍速Row(children: [ElevatedButton(onPressed: () {_controller.setPlaybackSpeed(1);},child: const Text(1倍速)),ElevatedButton(onPressed: () {_controller.setPlaybackSpeed(5);},child: const Text(5倍速))],),// 视频的进度条VideoProgressIndicator(_controller, allowScrubbing: true),],),): Container(),)chewie
video_player虽然是官方提供的插件但是很明显它只适合拿来简单的播放视频就比如前端的video标签功能也很少。在这里推荐一下chewie
简介
chewie是基于video_player实现的它额外提供了很多功能比如倍速、进度条、全屏以及其他的功能
官方文档 https://pub-web.flutter-io.cn/packages/chewie
安装
flutter pub add chewie默认的弹出菜单是这样的
可以通过设置optionsBuilder来进行自定义显示
class MyHomePage extends StatefulWidget {const MyHomePage({super.key, required this.title});final String title;overrideStateMyHomePage createState() _MyHomePageState();
}class _MyHomePageState extends StateMyHomePage {// 控制器late VideoPlayerController _controller;late ChewieController _chewieController;late PersistentBottomSheetControllerdynamic _bottomSheetController;// 初始化overridevoid initState() {super.initState();// 加载网络视频_controller VideoPlayerController.networkUrl(Uri.parse(https://www.tujuyun.com/pixabay/video/VideoBig/1024927/4006.mp4))..initialize().then((_) {setState(() {});_chewieController ChewieController(videoPlayerController: _controller,autoPlay: true,looping: true,optionsBuilder: (context, defaultOptions) async {// 这里面现在是只有一个设置倍速的我们把它拿出来// for (int i 0; i defaultOptions.length; i) {// print(默认选项${defaultOptions[i]});// }// await showDialogvoid(// context: context,// builder: (ctx) {// // return AlertDialog(// // content: ListView.builder(// // itemCount: defaultOptions.length,// // itemBuilder: (_, i) ActionChip(// // label: Text(defaultOptions[i].title),// // onPressed: () defaultOptions[i].onTap!(),// // ),// // ),// // );// },// );_bottomSheetController Scaffold.of(context).showBottomSheet((BuildContext context) {return SizedBox(height: 200,child: ListView(children: Widget[ListTile(leading: const Icon(Icons.speed),title: const Text(倍速),onTap: () defaultOptions[0].onTap!(),),const Divider(color: Colors.grey,thickness: 1.0,),ListTile(leading: const Icon(Icons.download),title: const Text(下载),onTap: () print(下载中..),),const Divider(color: Colors.grey,thickness: 1.0,),ListTile(leading: const Icon(Icons.close),title: const Text(关闭),onTap: () _bottomSheetController.close(),),],),);});},);});}overridevoid dispose() {super.dispose();_controller.dispose();_chewieController.dispose();}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: _controller.value.isInitialized // 判断是否已经加载完成? AspectRatio(// 设置视频播放的宽高比aspectRatio: _controller.value.aspectRatio,child: Chewie(controller: _chewieController,),): Container(),),);}
}注 chewie 还有很多其他高级功能比如自定义UI界面、设置弹幕等。需要好好看一下官方文档才能实现高级功能不过上面那个例子已经可以满足基本的使用了。
image_picker
简介 用于从相册中挑选图片、视频、使用相机拍摄照片。
官方文档 https://pub-web.flutter-io.cn/packages/image_picker
安装
flutter pub add image_picker示例读取单张图片
class _MyHomePageState extends StateMyHomePage {// 图片文件File? _image;// 错误信息String _error ;// 图片选择函数Futurevoid _pickImage() async {// 从相册中选择图片try {final pickedImage await ImagePicker().pickImage(source: ImageSource.gallery);if (pickedImage ! null) {setState(() {_image File(pickedImage.path);});}} catch (e) {setState(() {_error e.toString();});}}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: Column(mainAxisAlignment: MainAxisAlignment.center,children: [// 图片存在则显示if (_image ! null)Image.file(_image!,width: 200,height: 200,),// 如果错误信息存在if (_error.isNotEmpty) Text(错误$_error),const SizedBox(height: 20,),ElevatedButton(onPressed: _pickImage, child: const Text(从相册里选取图片))],),),);}
}看了一下好像不能设置选择的图片格式只能设置大小、质量 如果设置为ImagePicker().pickImage(source: ImageSource.camera) 这是调用摄像头来进行获取图片
示例读取多张图片
class _MyHomePageState extends StateMyHomePage {// 图片文件列表final ListFile _pickedFileList [];// 错误信息String _error ;// 图片选择函数Futurevoid _pickImage() async {// 从相册中选择图片try {final pickedImageList await ImagePicker().pickMultiImage();if (pickedImageList.isNotEmpty) {for (XFile image in pickedImageList) {_pickedFileList.add(File(image.path));}setState(() {});}} catch (e) {setState(() {_error e.toString();});}}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: Column(mainAxisAlignment: MainAxisAlignment.center,children: [Expanded(child: ListView.builder(itemCount: _pickedFileList.length,itemBuilder: (context, index) {return Image.file(_pickedFileList[index],width: 200,height: 200,);})),// 如果错误信息存在if (_error.isNotEmpty) Text(错误$_error),const SizedBox(height: 20,),ElevatedButton(onPressed: _pickImage, child: const Text(从相册里选取图片))],),),);}
}要长按图片才能够一次选择多个最后在点击右上角的选择。轻触会直接选中图片。另外看了下pickMultiImage里的入参好像不支持限制图片的个数
示例选择单个视频
选择视频稍微复杂一点还需要借助video_player等插件才能更进行预览。
class _MyHomePageState extends StateMyHomePage {// 错误信息String _error ;// 视频信息late File _video;// 视频播放器VideoPlayerController? _videoPlayerController;Futurevoid? _videoPlayerInitializer;// 选择视频Futurevoid _pickVideo() async {// 从相册中选择视频try {final pickedVideo await ImagePicker().pickVideo(source: ImageSource.gallery);if (pickedVideo ! null) {setState(() {_video File(pickedVideo.path);_videoPlayerController VideoPlayerController.file(_video);_videoPlayerInitializer _videoPlayerController!.initialize();// 播放视频_videoPlayerController!.play();});}} catch (e) {setState(() {_error e.toString();});}}overridevoid dispose() {_videoPlayerController?.dispose();super.dispose();}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: Column(mainAxisAlignment: MainAxisAlignment.center,children: [if (_videoPlayerController ! null)FutureBuilder(future: _videoPlayerInitializer,builder: (BuildContext context, AsyncSnapshotvoid snapshot) {if (snapshot.connectionState ConnectionState.done) {return SizedBox(width: 300,height: 200,child: AspectRatio(aspectRatio:1.5,child: VideoPlayer(_videoPlayerController!),),);} else {return const CircularProgressIndicator();}},),// 如果错误信息存在if (_error.isNotEmpty) Text(错误$_error),const SizedBox(height: 20,),ElevatedButton(onPressed: _pickVideo, child: const Text(从相册里选取视频))],),),);}
}file_picker
简介 一个包允许您使用本机文件资源管理器来选择单个或多个文件具有扩展筛选支持。
官方文档 https://pub-web.flutter-io.cn/packages/file_picker
安装
flutter pub add file_picker示例选择单个文件
class _MyHomePageState extends StateMyHomePage {// 错误信息String _error ;// 文件路径String _filePath ;// 选择文件Future _pickFile() async {try {FilePickerResult? result await FilePicker.platform.pickFiles(dialogTitle: 选择图片,type: FileType.image, // 设置文件的类型);if (result ! null) {setState(() {_filePath result.files.single.path!;});}} catch (e) {setState(() {_error e.toString();});}}overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: Text(widget.title),),body: Center(child: Column(mainAxisAlignment: MainAxisAlignment.center,children: [// File 是 io包下的_filePath ? const Text(未选择文件) : Image.file(File(_filePath)),// 如果错误信息存在if (_error.isNotEmpty) Text(错误$_error),const SizedBox(height: 20,),ElevatedButton(onPressed: _pickFile, child: const Text(选择一个图片))],),),);}
}示例选择多个文件
FilePickerResult? result await FilePicker.platform.pickFiles(allowMultiple: true);if (result ! null) {ListFile files result.paths.map((path) File(path)).toList();
} else {// User canceled the picker
}其他功能略可以自行查看官方文档
