dart

问题 I want to compress a string in Dart (in the browser). I tried this: import 'package:archive/archive.dart'; [...] List<int> stringBytes = UTF8.encode(myString); List<int> gzipBytes = new GZipEncoder().encode(stringBytes); String compressedString = UTF8.decode(gzipBytes, allowMalformed: true); Obviously UTF8.decode is not intended for this and it doesn't work (file is unreadable). What is the right way to compress a string in Dart? 回答1: The compressed list of bytes is probably not a valid UTF8

问题 I want to compress a string in Dart (in the browser). I tried this: import 'package:archive/archive.dart'; [...] List<int> stringBytes = UTF8.encode(myString); List<int> gzipBytes = new GZipEncoder().encode(stringBytes); String compressedString = UTF8.decode(gzipBytes, allowMalformed: true); Obviously UTF8.decode is not intended for this and it doesn't work (file is unreadable). What is the right way to compress a string in Dart? 回答1: The compressed list of bytes is probably not a valid UTF8

问题 I'm trying to run my app after importing intl, but it won't work. In the pubspec.yaml file I have: intl: ^0.15.8 I've imported the package in three ways after some research, just to be sure. But only the first one (intl.dart) seems to be used : import "package:intl/intl.dart"; import "package:intl/intl_browser.dart"; //unused import import "package:intl/intl_standalone.dart"; //unused import I'm using it this way : DateFormat("dd-MM-yyyy").format(_chosenDate) My error after flutter run is:

问题 I have been trying to save a list of lists using shared preferences in dart. For example, I have a list List data = [["dave","21","M"],["steven","22","F"]] and I am trying to save and load as it is but app keeps throwing Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'List<String>' I have tried converting the 2d list into a list using List new_data = data.expand((i) => i).toList(); and then saving it. But still, the exception persists even though it is a list containing

问题 This is the problem: notification is received by the app both with app in foreground or background (or terminated) but the snackbar for notification when the app is used doesn't work. I'm new in flutter so maybe I did some huge mistake. I am showing my code below. If you want more information just ask and thanks for the help! // Import Package import 'dart:io'; import 'package:app_gap_go/pages/admin/modifySingleMeeting.dart'; import 'package:cloud_firestore/cloud_firestore.dart'; import

问题 This question already has answers here : What is the difference between the “const” and “final” keywords in Dart? (12 answers) Closed 2 years ago . So I was doing the first example for Flutter, and under Step 4: Create an infinite scrolling ListView , I encountered this piece of code: class RandomWordsState extends State<RandomWords> { final _suggestions = <WordPair>[]; final _biggerFont = const TextStyle(fontSize: 18.0); ... } But I found the following line a little spooky. final _biggerFont

问题 This question already has answers here : What is the difference between the “const” and “final” keywords in Dart? (12 answers) Closed 2 years ago . So I was doing the first example for Flutter, and under Step 4: Create an infinite scrolling ListView , I encountered this piece of code: class RandomWordsState extends State<RandomWords> { final _suggestions = <WordPair>[]; final _biggerFont = const TextStyle(fontSize: 18.0); ... } But I found the following line a little spooky. final _biggerFont

问题 I am trying to use PlatformViews in Flutter to show Swift code natively in my Flutter app, however my app is crashing with my current code. This is my AppDelegate currently where I am invoking my method channel: import Foundation @UIApplicationMain @objc class AppDelegate: FlutterAppDelegate, TJPlacementDelegate { var p = TJPlacement() override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { let

问题 I am trying to use PlatformViews in Flutter to show Swift code natively in my Flutter app, however my app is crashing with my current code. This is my AppDelegate currently where I am invoking my method channel: import Foundation @UIApplicationMain @objc class AppDelegate: FlutterAppDelegate, TJPlacementDelegate { var p = TJPlacement() override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { let

问题 I am writing this flutter code where I have Image in an Image widget and I want to convert it into File so that I can upload it to Firebase Storage. Image _image = Image.asset('assets\images\profile.png'); File _fileImage = convertToFile(_image); //upload _fileImage to Firebase Storage code I need the File convertToFile(Image img) function. 回答1: Special thanks to sami kanafani. This is my solution (works perfectly for me): import 'dart:async'; import 'dart:io'; import 'package:flutter