Flutter文件上传下载教程

Flutter文件上传下载教程

3 回复

抱歉，我无法提供完整的教程。但你可以搜索"Flutter 文件上传下载教程"，有很多博主分享了相关经验。

更多关于Flutter文件上传下载教程的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html


抱歉，作为屌丝程序员，我还没研究过Flutter的文件上传下载功能。

在Flutter中，文件的上传和下载可以通过http或dio等网络库来实现。以下是一个简单的教程，展示如何使用dio库进行文件的上传和下载。

1. 添加依赖

首先，在pubspec.yaml文件中添加dio依赖：

dependencies:
  flutter:
    sdk: flutter
  dio: ^4.0.0

然后运行flutter pub get来安装依赖。

2. 文件上传

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:file_picker/file_picker.dart';

class FileUploadPage extends StatefulWidget {
  @override
  _FileUploadPageState createState() => _FileUploadPageState();
}

class _FileUploadPageState extends State<FileUploadPage> {
  Dio dio = Dio();

  Future<void> uploadFile() async {
    FilePickerResult? result = await FilePicker.platform.pickFiles();

    if (result != null) {
      PlatformFile file = result.files.first;
      FormData formData = FormData.fromMap({
        "file": await MultipartFile.fromFile(file.path!, filename: file.name),
      });

      try {
        var response = await dio.post(
          "https://your-server.com/upload",
          data: formData,
        );
        print("File uploaded: ${response.data}");
      } catch (e) {
        print("Error uploading file: $e");
      }
    } else {
      print("No file selected");
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("File Upload"),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: uploadFile,
          child: Text("Upload File"),
        ),
      ),
    );
  }
}

3. 文件下载

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'dart:io';

class FileDownloadPage extends StatefulWidget {
  @override
  _FileDownloadPageState createState() => _FileDownloadPageState();
}

class _FileDownloadPageState extends State<FileDownloadPage> {
  Dio dio = Dio();

  Future<void> downloadFile() async {
    String url = "https://your-server.com/file.pdf";
    String fileName = "file.pdf";

    try {
      var dir = await getApplicationDocumentsDirectory();
      String savePath = "${dir.path}/$fileName";
      await dio.download(url, savePath);
      print("File downloaded to: $savePath");
    } catch (e) {
      print("Error downloading file: $e");
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("File Download"),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: downloadFile,
          child: Text("Download File"),
        ),
      ),
    );
  }
}

4. 运行应用

将上述代码分别放入两个不同的页面中，并在main.dart中设置路由，即可实现文件的上传和下载功能。

注意事项

  • 确保服务器端支持文件上传和下载。
  • 处理网络请求时，建议使用try-catch来捕获异常。
  • 文件下载时，确保应用有写入外部存储的权限。

通过以上步骤，你可以在Flutter应用中实现文件的上传和下载功能。

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