dart

问题 I had an another issue before using 'Provider' package with 'PersistentBottomNavBar' package in my flutter app. So after solving that issue, immediately I got another one. There is my source code. When I run this code my Android emulator crushes. With the following error message: The method 'map' was called on null. Receiver: null. Tried calling: map(Closure: (PersistentBottomNavBarItem) => Flexible) import 'package:flutter/cupertino.dart'; import 'package:flutter/services.dart'; import

问题 Exception in thread "main" javax.net.ssl.SSLException: Connection has been shutdown: javax.net.ssl.SSLException: Tag mismatch! at sun.security.ssl.SSLSocketImpl.checkEOF(SSLSocketImpl.java:1533) at sun.security.ssl.AppInputStream.available(AppInputStream.java:60) at java.io.BufferedInputStream.available(BufferedInputStream.java:410) at sun.net.www.MeteredStream.available(MeteredStream.java:170) code countinues.... at java.io.FilterInputStream.close(FilterInputStream.java:181) at sun.net.www

问题 Exception in thread "main" javax.net.ssl.SSLException: Connection has been shutdown: javax.net.ssl.SSLException: Tag mismatch! at sun.security.ssl.SSLSocketImpl.checkEOF(SSLSocketImpl.java:1533) at sun.security.ssl.AppInputStream.available(AppInputStream.java:60) at java.io.BufferedInputStream.available(BufferedInputStream.java:410) at sun.net.www.MeteredStream.available(MeteredStream.java:170) code countinues.... at java.io.FilterInputStream.close(FilterInputStream.java:181) at sun.net.www

问题 I wanted to change the package name of my project so I changed the applicationId in build.gradle and in android.xml . I changed package name using below guide https://medium.com/@skyblazar.cc/how-to-change-the-package-name-of-your-flutter-app-4529e6e6e6fc Firebase database was linked with my project so I thought I had to change the package name in Firebase too. So, I added new app in Firebase with UPDATED package name of the project and added SHA key as required. After doing all this I

问题 I wanted to change the package name of my project so I changed the applicationId in build.gradle and in android.xml . I changed package name using below guide https://medium.com/@skyblazar.cc/how-to-change-the-package-name-of-your-flutter-app-4529e6e6e6fc Firebase database was linked with my project so I thought I had to change the package name in Firebase too. So, I added new app in Firebase with UPDATED package name of the project and added SHA key as required. After doing all this I

问题 here is the complete output : I tried switching to stable channel and ran these commands already. flutter channel stable flutter upgrade flutter run Even on stable channel the error doesn't go ! C:\Users\Rudr\Documents\GitHub\Flutter-Facial-Attendance-App\facatte>flutter run Launching lib\main.dart on SM M315F in debug mode... Plugin project :firebase_core_web not found. Please update settings.gradle. FAILURE: Build failed with an exception. * What went wrong: Could not determine the

问题 I am trying to ask the user to select the type of item in the first dropdown and then select from its corresponding available colours in the second dropdown. However, when after I have selected a colour (i.e. white) and now want to switch to another item that does not have this colour, an error is thrown: "There should be exactly one item with [DropdownButton]'s value: white. \nEither zero or 2 or more [DropdownMenuItem]s were detected with the same value" Please help, I have already tried to

问题 here is the complete output : I tried switching to stable channel and ran these commands already. flutter channel stable flutter upgrade flutter run Even on stable channel the error doesn't go ! C:\Users\Rudr\Documents\GitHub\Flutter-Facial-Attendance-App\facatte>flutter run Launching lib\main.dart on SM M315F in debug mode... Plugin project :firebase_core_web not found. Please update settings.gradle. FAILURE: Build failed with an exception. * What went wrong: Could not determine the

问题 I have a layout made of a Column, one of its elements being a row (so that it takes the full width of the screen). Inside that row, I have a wrap, which content is pretty big and that I want to put inside a SingleChildScrollView. @override Widget build(BuildContext context) { return Scaffold( body: SafeArea( child: Container( padding: const EdgeInsets.all(kPaddingMainContainer), child: Column( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Row( mainAxisAlignment:

问题 I'm using an API which returns the value like this. [ { "store": "AMAZON" }, { "store": "FLIPKART" }, { "store": "WALMART" }, { "store": "ALIBABA" }, ] I need this to be in a drop down. I need a drop down button with this API data in it. Some one help please. I have tried many ways but nothing worked. 回答1: nigale try code: List<String> markets = []; // Or var markets = []; String _mySelection; @override void initState() { buidDropDownItems(); super.initState(); } // void buidDropDownItems()