flutter 显示缓存大小，清理缓存功能

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flutter 显示缓存大小，清理缓存功能

2023-08-22 09:47| 来源: 网络整理| 查看: 265

Flutter 获取应用缓存需要借助于path_provider插件。 path_provider 是一个用于查找文件系统上常用位置的Flutter插件。用来获取 Android 和 iOS 的缓存文件夹，然后再根据文件循环计算出缓存文件的大小。

以下是官方解释：

A Flutter plugin for finding commonly used locations on the filesystem. Supports iOS and Android.

目前可用最高版本为2.0.5。版本来源参考：path_provider 2.0.5

方法介绍 path_provider中获取文件夹的方法：

1、getTemporaryDirectory() ///< 在iOS上，对应NSTemporaryDirectory()；在Android上，对应getCacheDir。

2、getApplicationDocumentsDirectory() ///< 在iOS上，对应NSDocumentsDirectory；在Android上，对应AppData目录。

3、getExternalStorageDirectory()///< 在iOS上，抛出异常，在Android上，对应getExternalStorageDirectory。

以下是源码注释:

/// Path to the temporary directory on the device. /// /// Files in this directory may be cleared at any time. This does *not* return /// a new temporary directory. Instead, the caller is responsible for creating /// (and cleaning up) files or directories within this directory. This /// directory is scoped to the calling application. /// /// On iOS, this uses the `NSCachesDirectory` API. /// /// On Android, this uses the `getCacheDir` API on the context. Future getTemporaryDirectory() async { // TODO(amirh): remove this on when the invokeMethod update makes it to stable Flutter. // https://github.com/flutter/flutter/issues/26431 // ignore: strong_mode_implicit_dynamic_method final String path = await _channel.invokeMethod('getTemporaryDirectory'); if (path == null) { return null; } return Directory(path); } /// Path to a directory where the application may place files that are private /// to the application and will only be cleared when the application itself /// is deleted. /// /// On iOS, this uses the `NSDocumentsDirectory` API. /// /// On Android, this returns the AppData directory. Future getApplicationDocumentsDirectory() async { final String path = // TODO(amirh): remove this on when the invokeMethod update makes it to stable Flutter. // https://github.com/flutter/flutter/issues/26431 // ignore: strong_mode_implicit_dynamic_method await _channel.invokeMethod('getApplicationDocumentsDirectory'); if (path == null) { return null; } return Directory(path); } /// Path to a directory where the application may access top level storage. /// The current operating system should be determined before issuing this /// function call, as this functionality is only available on Android. /// /// On iOS, this function throws an UnsupportedError as it is not possible /// to access outside the app's sandbox. /// /// On Android this returns getExternalStorageDirectory. Future getExternalStorageDirectory() async { if (Platform.isIOS) throw UnsupportedError("Functionality not available on iOS"); // TODO(amirh): remove this on when the invokeMethod update makes it to stable Flutter. // https://github.com/flutter/flutter/issues/26431 // ignore: strong_mode_implicit_dynamic_method final String path = await _channel.invokeMethod('getStorageDirectory'); if (path == null) { return null; } return Directory(path); } 使用方法

1、pubspec.yaml文件下添加依赖库：path_provider: ^1.6.8。并执行flutter packages get操作，若出现问题，可适当降低依赖版本。

# 添加文件依赖 path_provider: ^1.6.8

2、导入头文件

import 'package:path_provider/path_provider.dart'; import 'dart:io';

页面初始化时循环获得缓存大小

double cache = 0.0; void initState() { getSize(); super.initState(); } getSize() async { final _tempDir = await getTemporaryDirectory(); double _cache = await Utils.getTotalSizeOfFilesInDir(_tempDir); setState(() { cache = _cache; }); } ClickItem( title: '清除缓存', content: Utils.renderSize(cache), onTap: () async { print('清除'); try { final _tempDir = await getTemporaryDirectory(); EasyLoading.show(status: '清除中'); await Utils.requestPermission(_tempDir); EasyLoading.dismiss(); EasyLoading.showSuccess('清除成功'); getSize(); } catch (err) { EasyLoading.dismiss(); EasyLoading.showError('清除失败'); } }, ),

Utils中的方法

import 'dart:io'; import 'dart:typed_data'; import 'dart:ui'; import 'package:permission_handler/permission_handler.dart'; static Future requestPermission(FileSystemEntity file) async { PermissionStatus status = await Permission.storage.status; await delDir(file); } static Future delDir(FileSystemEntity file) async { if (file is Directory && file.existsSync()) { print(file.path); final List children = file.listSync(recursive: true, followLinks: true); for (final FileSystemEntity child in children) { await delDir(child); } } try { if (file.existsSync()) { await file.delete(recursive: true); } } catch (err) { print(err); } } //循环获取缓存大小 static Future getTotalSizeOfFilesInDir(final FileSystemEntity file) async { // File if (file is File && file.existsSync()) { int length = await file.length(); return double.parse(length.toString()); } if (file is Directory && file.existsSync()) { List children = file.listSync(); double total = 0; if (children.length > 0) for (final FileSystemEntity child in children) total += await getTotalSizeOfFilesInDir(child); return total; } return 0; } //格式化文件大小 static String renderSize(value) { if (value == null) { return '0.0'; } List unitArr = [] ..add('B') ..add('K') ..add('M') ..add('G'); int index = 0; while (value > 1024) { index++; value = value / 1024; } String size = value.toStringAsFixed(2); return size + unitArr[index]; }

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flutter 显示缓存大小，清理缓存功能

flutter 显示缓存大小，清理缓存功能

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