dart

问题 I'm using VSCode to develop Flutter Apps, but, intellisense only shows up when I press space bar first. For instance when I create any widget within the widget tree, such as IconButton(icon:), the property 'icon' doesn't show up in intellisense when typing the first characters, like 'ic', only if I press the space bar, or after the property was completely typed and then if it is removed, the next time when typing, then the intellisense works fine. Does anyone else having the same issue? it is

问题 I have a GridView and I want to add a bannerAd after the gridview scroll ends. The bannerAd is called from the dependency https://github.com/kmcgill88/admob_flutter. The code for the GridView is as follows Widget build(BuildContext context) { SystemChrome.setEnabledSystemUIOverlays([]); return WillPopScope( onWillPop: () async { return true; }, child: Scaffold( body: Container( decoration: BoxDecoration( gradient: LinearGradient( colors: [const Color(0xFFFEFEFE), const Color(0xFFFEFEFE)],

问题 What I want to achieve is explained below:- To show several widgets by clicking a button. The dynamically displayed widgets are basically FlatButtons with Icons as child. So when I click these buttons, I want the icon to change. However, on testing it - I found that their state doesn't change. Below is a sample code import 'package:flutter/material.dart'; class Test extends StatefulWidget { @override _TestState createState() => _TestState(); } class _TestState extends State<Test> { IconData

问题 I was trying to get data from api and display it into DropDownButton I want to get country name and country id from api My code is: My get function List country_data = List(); String countryid; Future<String> country() async { final prefs = await SharedPreferences.getInstance(); final key = 'session_id'; final value = prefs.get(key ) ?? 0; var res = await http.get( Uri.encodeFull("http://husam.from-ar.com/api/api-ad/en/1"), headers: {"Accept": "application/json", "Authorization" : "$value", }

问题 I was trying to get data from api and display it into DropDownButton I want to get country name and country id from api My code is: My get function List country_data = List(); String countryid; Future<String> country() async { final prefs = await SharedPreferences.getInstance(); final key = 'session_id'; final value = prefs.get(key ) ?? 0; var res = await http.get( Uri.encodeFull("http://husam.from-ar.com/api/api-ad/en/1"), headers: {"Accept": "application/json", "Authorization" : "$value", }

问题 I'm trying to implement both a Drawer and the Bottom Navigation Bar. The below class NavigationHomeScreen is my home screen and when the user clicks a menu item in the Drawer the Changeindex function updates the screenView I would like to know how I can similarly update the screenView but from the BottomNavigationBarApp using the onTabTapped method. class NavigationHomeScreen extends StatefulWidget { @override _NavigationHomeScreenState createState() => _NavigationHomeScreenState(); } class

问题 I'm trying to create a basic Flutter app that has a a 2 by 2 grid of text inputs & a button below it. Initially, I just had the grid & no buttons with no problems: void main() => runApp(new App()); class App extends StatelessWidget { ... Widget build(BuildContext context) { return new MaterialApp( ... home: new InputWidget() ... class InputWidget extends StatefulWidget { Widget build(BuildContext context) { ... _InputWidgetState createState() => new _InputWidgetState(); ... class

问题 When I run my flutter app on Android Emulator it runs without errors but when I am running it on my mobile device it shows following error in Debug Console: Launching lib\main.dart on HD1901 in debug mode... FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':app:compileDebugKotlin'. > Could not resolve all artifacts for configuration ':app:debugCompileClasspath'. > Failed to transform artifact 'arm64_v8a_debug.jar (io.flutter:arm64_v8a_debug:1.0.0

问题 I have a Image inside a GestureDetector widget. I want to change this image when onTapDown is called, and then change it again when onTapUp is called. Is there possible to do that? In other app (Native Android app with java), I used to do it using a button and changing its background with a selector xml, like this: <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_focused="true" android:state_pressed="false" android:drawable="@drawable/image1" /> <item

问题 I have an idiot question. is it possible to run the build runner in an application compiled for dynamic code generation? 回答1: In a Flutter application, no. Flutter apps neither have the ability to dynamically evaluate Dart code, nor do they have access to the tools needed to parse and generate source code. 来源： https://stackoverflow.com/questions/61015321/run-flutter-builder-runner-in-compiled-app