dart

问题 I am creating whole year calender, How to get numbers of days of month in Flutter? e.g., January -> 31, Fabruary -> 28/29(as per year), March -> 31 So on... 回答1: You can use package https://pub.dev/packages/date_util With dateUtility.daysInMonth code snippet var dateUtility = DateUtil(); var day1 = dateUtility.daysInMonth(2, 2019); print(day1); var day2 = dateUtility.daysInMonth(2, 2018); print(day2); full code import 'package:flutter/material.dart'; import 'package:date_util/date_util.dart';

问题 This is problem, I have already installed flutter and dart plugin but its showing I haven't , I freshly installed both android studio and flutter as I just started it Doctor summary (to see all details, run flutter doctor -v): [√] Flutter (Channel stable`enter code here`, on Microsoft Windows) [√] Android toolchain - develop for Android devices (Android SDK version 30.0.3) [!] Android Studio (version 4.1.0) X Flutter plugin not installed; this adds Flutter specific functionality. X Dart

问题 This is problem, I have already installed flutter and dart plugin but its showing I haven't , I freshly installed both android studio and flutter as I just started it Doctor summary (to see all details, run flutter doctor -v): [√] Flutter (Channel stable`enter code here`, on Microsoft Windows) [√] Android toolchain - develop for Android devices (Android SDK version 30.0.3) [!] Android Studio (version 4.1.0) X Flutter plugin not installed; this adds Flutter specific functionality. X Dart

问题 It does not appear there is a clear interception of JS Promises by the Interop or dart2JS. ServiceWorkerContainer swContain = window.navigator.serworker; swContain.register(workerScriptURI,scope).then((ServiceWorkerRegistration rego){ /// Here confirm scope and the state, handle and unregister if required. )}; Yet it appears to be no way of pulling this off without wrapping the promise and a completer. When I then I can not get to work in a dependable fashion. Long post here: https://groups

问题 i am trying to pass variable in regex language DART `betweenLenth(val, field, [min = 4, max = 20]) { final RegExp nameExp = new RegExp(r'^\w{" + min + "," + max + "}$'); if (!nameExp.hasMatch(val)) return field + " must be between $min - $max characters "; }` thanks 回答1: A generic function to escape any literal string that you want to put inside a regex as a literal pattern part may look like escape(String s) { return s.replaceAllMapped(RegExp(r'[.*+?^${}()|[\]\\]'), (x) {return "\\${x[0]}";}

问题 I'm trying to put JSON body query parameters into http.get request. I tried to even follow this Flutter: Send JSON body for Http GET request but no luck there. No matter what I put into params variable I get all results from my backend. I have tested backend with postman and everything works fine Here is my code in flutter Future<List<Country>> fetchCountries(String name) async { final token = Provider.of<Auth>(context, listen: false).token; final params = {"name": "Uk"}; try { Uri uri = Uri

问题 I'm trying to build an archive by doing flutter build ios but I encounter a problem on Starting Xcode build $ flutter build ios Building com.example.example for the device (ios-release)... Automatically signing iOS for device deployment using specified development team in Xcode project: XXXXXX Running pod install... Starting Xcode build... ├─Building Dart code... I already build an archive one (last week) and it was working. Maybe this is due to flutter upgrade ? $ flutter doctor Doctor

问题 I'm trying to build an archive by doing flutter build ios but I encounter a problem on Starting Xcode build $ flutter build ios Building com.example.example for the device (ios-release)... Automatically signing iOS for device deployment using specified development team in Xcode project: XXXXXX Running pod install... Starting Xcode build... ├─Building Dart code... I already build an archive one (last week) and it was working. Maybe this is due to flutter upgrade ? $ flutter doctor Doctor

问题 Is it possible to emulate a Flutter app in debug mode on an iphone connected to a windows 10 machine using VS Code? it all sounds like it wont work when I type it out :) 回答1: No, you need Xcode installed for that and that runs only on OSX. 来源： https://stackoverflow.com/questions/52175299/debug-flutter-on-iphone-using-vs-code-on-windows-10

问题 Is there way to late initialize for final variables. The problem is many values initialized with entry point to the class, which is not constructor. Hence they cannot be final right now. But in scope of particular class they will not be changed. For ex. Controller controller; double width; void setup(final itemWidth) { controller = MyController(); width = itemWidth; } Could it be possible? Right now I see only solution as a annotation. You might think it's for visual effect. But in fact it