Question

在我的flutter应用程序中，我将一些图像存储在缓存目录中，并将一些文件存储在应用程序文档目录中，现在我想为用户增加删除缓存目录和应用程序目录的可能性，我该如何实现？

Answer 1

然后尝试以下代码：

  Future<void> _deleteCacheDir() async {
    final cacheDir = await getTemporaryDirectory();

    if (cacheDir.existsSync()) {
      cacheDir.deleteSync(recursive: true);
    }
  }

  Future<void> _deleteAppDir() async {
    final appDir = await getApplicationSupportDirectory();

    if(appDir.existsSync()){
      appDir.deleteSync(recursive: true);
    }
  }

Answer 2

此代码可以为您提供帮助：

import 'dart:async';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';

void main() {
  runApp(
    MaterialApp(
      title: 'Reading and Writing Files',
      home: FlutterDemo(storage: CounterStorage()),
    ),
  );
}

class CounterStorage {
  Future<String> get _localPath async {
    final directory = await getApplicationDocumentsDirectory();

    return directory.path;
  }

  Future<File> get _localFile async {
    final path = await _localPath;
    return File('$path/counter.txt');
  }

  Future<int> readCounter() async {
    try {
      final file = await _localFile;

      // Read the file
      String contents = await file.readAsString();

      return int.parse(contents);
    } catch (e) {
      // If encountering an error, return 0
      return 0;
    }
  }

  Future<File> writeCounter(int counter) async {
    final file = await _localFile;

    // Write the file
    return file.writeAsString('$counter');
  }
}

class FlutterDemo extends StatefulWidget {
  final CounterStorage storage;

  FlutterDemo({Key key, @required this.storage}) : super(key: key);

  @override
  _FlutterDemoState createState() => _FlutterDemoState();
}

class _FlutterDemoState extends State<FlutterDemo> {
  int _counter;

  @override
  void initState() {
    super.initState();
    widget.storage.readCounter().then((int value) {
      setState(() {
        _counter = value;
      });
    });
  }

  Future<File> _incrementCounter() {
    setState(() {
      _counter++;
    });

    // Write the variable as a string to the file.
    return widget.storage.writeCounter(_counter);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Reading and Writing Files')),
      body: Center(
        child: Text(
          'Button tapped $_counter time${_counter == 1 ? '' : 's'}.',
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

此外，您还可以在这里找到非常有用的文档： https://github.com/flutter/samples/blob/master/INDEX.md

如何在Flutter中删除缓存和应用程序目录

2 个答案: