How do you recursively remove an entire directory in Dart along with all the files?
For example:
/path/to/project/foo.dart
/path/to/project/remove/all/of/these
It's easier than it sounds.
If I understood you right, it would go like this:
import 'dart:io';
main() {
// Deletes the directory "remove" with all folders and files under it.
new Directory('remove').delete(recursive: true);
}
Related
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.
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.
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.
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
#Suragch 's answer is right. Except the version of path_provider that you want to use now is:
path_provider: ^2.0.9
Suppose I have this:
benchmark.dart:
library benchmark;
benchmark() {...}
app.dart:
import 'benchmark.dart'; // functions from this lib are now accessible in this file
export 'benchmark.dart'; // does this make them accessible in all files imported below?
import 'model.dart';
void main() {
doSomething();
}
model.dart
doSomething() {
benchmark(); // => Error, no such method, unless
// I import 'benchmark.dart' above in this file!
}
Is this the right behavior? How do I make benchmark accessible without importing the lib in model.dart?
You have to make the imports in every library you want to use other libraries.
What you might do is to join several files to one library using part 'model.dart'; (parent file) and part of app; (linked file).
Then the types and functions imported in the parent file are available in all files of this library.
I want to know what the current directory is. I don't want to shell out to run pwd. Is there an easy way to do this in Dart?
Indeed there is!
import 'dart:io';
main() {
Directory current = Directory.current;
}
Note: this only works on the command-line, not in the browser.
Read more about the API docs for Directory.current.
Directory.current.path does it if you want a string, Directory.current for a Directory.
(note: Directory is defined in dart:io)
Dart's Web UI performs a compile step which puts the generated files into an "out" folder. I can't figure out how to get an image to be placed in that out folder, though. Does anyone know how?
I have the images in the web folder in a folder called img, although I've also tried putting them directly in web. Should I create a top level folder named resources and put them in there instead?
I had the same problem, and have almost solved it by updating my build.dart to include a copy of the img folder into the out folder.
import 'dart:io';
import 'dart:async';
import 'package:web_ui/component_build.dart';
// Ref: http://www.dartlang.org/articles/dart-web-components/tools.html
// Actually ... https://github.com/sethladd/dart-web-components-tests/blob/master/build.dart
main() {
var args = new List.from(new Options().arguments);
// args.addAll(['--', '--no-rewrite-urls']);
Future dwc = build(args, ['web/index.html']);
dwc
.then((_) => Process.run('cp', ['-fR', 'web/img', 'web/out']));
}
In the above I've added a command to run "cp" (I'm on a Mac) of web/img to web/out.
I say almost solved it because those image in the img folder also end up being copied directly into the out folder as well as out/img, which isn't ideal but doesn't harm anything for me just now. I believe these extra copies are from build.dart being triggered by the copy, haven't found a way to stop this yet.
I know you can use the library, import and even #import, but which is correct?
I have got two files, MainClass.dart and Library.Dart, and I want to add a reference to Library.dart in MainClass.dart. How can I do that?
Firstly let me just preface this by saying please do not use the hash symbol before import or library or anything else. This is an old syntax that is being deprecated. So we no longer want to use #import('...') The correct syntax is:
import 'some_file.dart';
That said, there are two different things we can do to access different dart source files within our current file. The first is to import the file. We use this such as in your case when you want to bring a different library into the current file (or more accurately current library).
Usually if your files are in the same directory, or a sub directory of the current one we would import them like this:
import 'lib/library.dart';
However If you are using the pub package layout you can also use some special short-cut references as well to import files (particularly from other packages you've imported). I highly suggest reading the documents on the pub site, as most applications and libraries are designed with this in mind. It also has suggestions on best naming conventions such as filenames in all lower case, and using underscore for spaces, and directory layouts.
The other important thing to know about bringing a dart file into another file, is that we can use the part and part of directives. This used to be called #source but was changed (with the removal of the hash sign) to reduce confusion. The part directive is used when we want to write a single library which spans multiple files. Say for instance you have an Awesome Library, which is starting to get a little large for a single file. We will create the main file of the library (not to be confused with the main method). This file will usually have the same name as the library itself.
// awesome_library.dart
library awesome_library;
import 'dart:math';
import '...';
// this injects all the content of secret_file.dart
// into this file right here almost as if it was
// here in the first place.
part 'src/secret_file.dart';
// The rest of our file here
// ...
The part directive basically takes everything from our src/secret_file.dart and inserts it into that part of the file. This allows us to split our huge Awesome Library into multiple smaller files that are easier to maintain. While not specifically required, it is helpful to use the part of directive in our secret_file.dart to help the editor know that it is "part of" the library.
// secret_file.dart
part of awesome_library;
// ... Rest of our secret_file code below.
Note that when using a part file like this, the part(s) (that is everything that is not the main file of the library) cannot import or use library declarations themselves. They import whatever is imported into the the main file, but they cannot add any additional imports.
For more information about library see this link.
Importing your own created libraries:
You will be importing the filename.dart and not the name of your library.
So if the name of your library is: myLib and it is saved in the file: someDartFile.dart you will have to
import 'someDartFile.dart';
If you have on Windows a library at: K:\SomeDir\someFile.dart you will need to write:
import '/K:/SomeDir/someFile.dart';
example:
import 'LibraryFile.dart'; //importing myLib
void main(){
//a class from myLib in the LibraryFile.dart file
var some = new SomeClassFromMyLibrary();
}
myLib in LibraryFile.dart:
library myLibrary;
import 'dart:math';
class SomeClassFromMyLibrary{
String _str = "this is some private String only to myLibrary";
String pubStr = "created instances of this class can access";
}
Here a full example.
//TestLib.dart
import 'LibFile.dart'; //SomeLibrary
void main() {
print("Hello, World!");
LibFile l = new LibFile();
print(l.publicString);//public
print(l.getPrivateString);//private
print(l.getMagicNumber); //42
}
//LibFile.dart
library SomeLibrary;
part 'LibFile2.dart';
class LibFile {
String _privateString = "private";
String publicString = "public";
String get getPrivateString => _privateString;
int get getMagicNumber => new LibFile2().number;
}
//LibFile2.dart
part of SomeLibrary;
class LibFile2 {
int number = 42;
}
Although i am answering very late, but the answer may help new developer.
Always use pubspec.yaml file in your dart package(application/library).
once you run pub get command it will add your local library in the dependencies list in .packages file.
Consider i have following project structure.
To refer to the content of greeting.dart in my main.dart file i should add the library as below
import 'package:my_project_name/greeting.dart'
Once imported we can use the content of greeting.dart file in our main.dart file.
Note: we have not used the actual path as you can see 'lib' directory is missing.
First make sure that's the name which you have mentioned in pubspec.yaml and the file you want to import are sharing the exact same name
example:
pubspec.yaml
name: flutter_wordpress_app
description: flutter wordpress app
...
....
// dirOne/dirTwo/greeting.dart
class FavArticleBloc {
// Your code goes here
}
import 'package:flutter_wordpress_app/dirOne/dirTwo/greeting.dart'
void main(){
var some = new FavArticleBloc();
}
But
in the main.dartyou don't need to specify
import 'package:flutter_wordpress_app
just do like below
import 'dirOne/dirTwo/greeting.dart