使用flutter框架开发安卓应用时 我怎样做到使用http与flutter_downloader自动远程下载安装包 并进行更新
您可以按照以下步骤来实现自动远程下载安装包并进行更新：
- 导入http和flutter_downloader插件
在项目的pubspec.yaml文件中添加http和flutter_downloader插件依赖：
dependencies:
http: ^0.13.3
flutter_downloader: ^1.5.1
- 下载和安装应用程序更新
使用http插件下载应用程序更新并使用flutter_downloader将其安装。您可以使用以下代码来实现此操作：
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:flutter_downloader/flutter_downloader.dart';
import 'package:path_provider/path_provider.dart';
import 'dart:io';
class UpdateApp extends StatefulWidget {
final String appUrl;
UpdateApp({Key key, this.appUrl}) : super(key: key);
@override
_UpdateAppState createState() => _UpdateAppState();
}
class _UpdateAppState extends State<UpdateApp> {
String _taskId;
String _localPath;
@override
void initState() {
super.initState();
downloadFile();
}
Future<void> downloadFile() async {
final directory = await getExternalStorageDirectory();
_localPath = directory.path;
final taskId = await FlutterDownloader.enqueue(
url: widget.appUrl,
savedDir: _localPath,
showNotification: true,
openFileFromNotification: true);
setState(() {
_taskId = taskId;
});
FlutterDownloader.registerCallback((id, status, progress) {
if (status == DownloadTaskStatus.complete) {
installApp();
}
});
}
Future<void> installApp() async {
final taskId = await FlutterDownloader.enqueue(
url: widget.appUrl,
savedDir: _localPath,
showNotification: true,
openFileFromNotification: true,
fileName: 'app.apk');
setState(() {
_taskId = taskId;
});
FlutterDownloader.registerCallback((id, status, progress) async {
if (status == DownloadTaskStatus.complete) {
final file = File('$_localPath/app.apk');
await installApk(file.path);
}
});
}
Future<void> installApk(String filePath) async {
final result = await FlutterDownloader.open(taskId: _taskId);
if (result == DownloadTaskStatus.failed) {
return;
}
}
@override
Widget build(BuildContext context) {
return Container();
}
}
在此示例中，我们使用http插件下载应用程序更新，使用flutter_downloader将应用程序更新安装到设备上。我们使用了getExternalStorageDirectory()来获取设备的外部存储目录，将文件下载到该目录。我们还使用flutter_downloader的回调函数来检测下载任务的状态和进度，并使用installApk()方法来安装应用程序更新。
- 检查应用程序更新
您可以使用http插件来检查应用程序更新是否可用。您可以使用以下代码来实现此操作：
import 'package:http/http.dart' as http;
import 'dart:convert';
class CheckUpdate {
final String currentVersion;
final String apiUrl;
CheckUpdate({this.currentVersion, this.apiUrl});
Future<bool> isUpdateAvailable() async {
final response = await http.get(apiUrl);
final data = json.decode(response.body);
final latestVersion = data['version'];
if (currentVersion != latestVersion) {
return true;
}
return false;
}
}
在此示例中，我们使用http插件从远程API获取应用程序最新版本号，并将其与当前版本进行比较。如果版本不同，则返回true，表示应用程序更新可用。
- 实现自动更新
您可以将上述步骤组合在一起，以实现自动检查和安装应用程序更新。您可以使用以下代码来实现此操作：
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:flutter_downloader/flutter_downloader.dart';
import 'package:path_provider/path_provider.dart';
import 'dart:io';
import 'dart:convert';
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
final String apiUrl = 'https://api.example.com/version';
final String appUrl = 'https://example.com/app.apk';
final String currentVersion = '1.0.0';
bool _isUpdateAvailable = false;
@override
void initState() {
super.initState();
checkForUpdate();
}
Future<void> checkForUpdate() async {
final checkUpdate = CheckUpdate(currentVersion: currentVersion, apiUrl: apiUrl);
final isUpdateAvailable = await checkUpdate.isUpdateAvailable();
setState(() {
_isUpdateAvailable = isUpdateAvailable;
});
if (isUpdateAvailable) {
showUpdateDialog();
}
}
Future<void> showUpdateDialog() async {
final result = await showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text('New Update Available'),
content: Text('A new update is available. Would you like to download and install it?'),
actions: <Widget>[
FlatButton(
child: Text('Cancel'),
onPressed: () {
Navigator.of(context).pop('cancel');
},
),
FlatButton(
child: Text('Download and Install'),
onPressed: () {
Navigator.of(context).pop('download');
},
),
],
);
});
if (result == 'download') {
downloadAndInstall();
}
}
Future<void> downloadAndInstall() async {
final directory = await getExternalStorageDirectory();
final localPath = directory.path;
final taskId = await FlutterDownloader.enqueue(
url: appUrl,
savedDir: localPath,
showNotification: true,
openFileFromNotification: true,
fileName: 'app.apk');
FlutterDownloader.registerCallback((id, status, progress) async {
if (status == DownloadTaskStatus.complete) {
final file = File('$localPath/app.apk');
await installApk(file.path);
}
});
}
Future<void> installApk(String filePath) async {
final result = await FlutterDownloader.open(taskId: _taskId);
if (result == DownloadTaskStatus.failed) {
return;
}
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Auto Update App'),
),
body: Center(
child: _isUpdateAvailable ? Text('Update Available') : Text('No Update Available'),
),
),
);
}
}
class CheckUpdate {
final String currentVersion;
final String apiUrl;
CheckUpdate({this.currentVersion, this.apiUrl});
Future<bool> isUpdateAvailable() async {
final response = await http.get(apiUrl);
final data = json.decode(response.body);
final latestVersion = data['version'];
if (currentVersion != latestVersion) {
return true;
}
return false;
}
}
void main() {
runApp(MyApp());
}
在此示例中，我们使用了CheckUpdate类来检查应用程序更新是否可用。如果更新可用，则弹出一个对话框，询问用户是否要下载和安装更新。如果用户选择下载和安装更新，则使用downloadAndInstall()方法来下载和安装应用程序更新。我们还使用FlutterDownloader的回调函数来检测下载任务的状态和进度，并使用installApk()方法来安装应用程序更新。最后，我们将_isUpdateAvailable状态变量用于在应用程序中显示更新是否可用的消息。
原文地址: https://www.cveoy.top/t/topic/bF3E 著作权归作者所有。请勿转载和采集!