Flutter中如何读写一个文本文件

Question

How do you read text from a file and write text to a file?

I've been learning about how to read and write text to and from a file. I found another question about reading from assets , but that is not the same. I will add my answer below from what I learned from the documentation.

Answer 1

Setup

Add the following plugin in pubspec.yaml :

dependencies:
  path_provider: ^1.6.27

Update the version number to whatever is current .

And import it in your code.

import 'package:path_provider/path_provider.dart';

You also have to import dart:io to use the File class.

import 'dart:io';

Writing to a text file

_write(String text) async {
  final Directory directory = await getApplicationDocumentsDirectory();
  final File file = File('${directory.path}/my_file.txt');
  await file.writeAsString(text);
}

Reading from a text file

Future<String> _read() async {
  String text;
  try {
    final Directory directory = await getApplicationDocumentsDirectory();
    final File file = File('${directory.path}/my_file.txt');
    text = await file.readAsString();
  } catch (e) {
    print("Couldn't read file");
  }
  return text;
}

Notes

• You can also get the path string with join(directory.path, 'my_file.txt') but you need to import 'package:path/path.dart' .
• Flutter's Official Documentation of Reading and Writing Files
• This works for iOS, Android, Linux and MacOS but not for web.

Answer 2

As additional info to @Suragch's answer, if you want to find the file you created, you can do as the images show:

And then inside that data folder, go again to a folder named data and search for your package, and then go to:

If you happen to create new files, in order to be able to see them, just right click and click Synchronize .

Answer 3

An another way to pull the file from the device is by using adb pull command. You can find the file path by debugging the code and then use adb pull command. adb is located in Android SDK -> platform-tools directory.

./adb pull /storage/emulated/0/Android/data/com.innovate.storage.storage_sample/files/sample.txt ~/Downloads

Answer 4

@Suragch 's answer is right. Except the version of path_provider that you want to use now is:

path_provider: ^2.0.9