Flutter | 易学教程

How to delete data using http.delete Flutter

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问题 I'm Learning CRUD( Create,Read,Update,Delete) using rest api , I'm already GET & POST data, How to implement "http.delete()" in Flutter ? I'm already Using this function, i can get ID for deleting data, but not deleting. Future deleteMahasiswa(Map<String, dynamic> id) async { final response = await http.delete('${Urls.BASE_API_URL}/mahasiswa/delete?id=$id'); return response.statusCode == 200; } class Urls { static const BASE_API_URL = 'http://192.168.43.159/wpu-rest-server/apii/'; static

Flutter does not generate a lib/main.dart

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问题 After opening a simulator, when I run: flutter create first_app on my Dev folder directory in my User account, and then I run: cd first_app flutter run I am given an error message saying that there is no lib/main.dart directory, which is true; flutter didn't create a main file/method for me. This consequently makes it impossible to run the app. I am only starting out with Flutter, so I have yet to learn how to create a main method etc... My visualstudio code has already installed the Flutter

Flutter OnChanged behaviour in Radios with multiple groups not working as expected

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问题 Hi The problem is I have multiple groups of RadioButtons hence can't figure out how onChanged method will work for each group. I have a list of students and want to make a widget where a teacher can mark attendance of students by clicking on one of the Radio Buttons( present,absent,holiday,half day etc.) Here is the implementation @override Widget build(BuildContext context) { print('number students ${studentList.students.length.toString}'); return ListView.builder( itemCount: studentList

How to tell flutter widget that keyboard doesnt change screen size

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问题 I was looking for a way to split my background in my flutter application using a wave, and I found this piece of code: Design a background from 2 images in flutter It works perfectly, and I could adapt it to my needs. The only thing I don't understand is that every time I open my keyboard and type something into an input field, the wave is recalculated. I thought if I used a StatelessWidget, that wouldn't happen. Does anyone have an idea how I can fix this problem? Thank you very much. 来源：

在应用开发中，我为什么选择 Flutter 而不是 React Native ？

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点击上方“ 逆锋起笔 ”，公众号回复 pdf 领取大佬们推荐的学习资料作者 | Sanket Doshi 译者 | 核子可乐策划 | 李俊辰作为一位开发人员，我想在本文中与大家聊聊跨平台开发领域的两大核心选项——Flutter 与 React Native 框架，并介绍我自己为什么更偏爱 Flutter。时至今日，React Native 与 Flutter 已经成为两大领先跨平台开发框架。这两套框架之所以极具人气，是因为它们不仅能够简化开发、代码重用等常规工作，同时提供高度原生化的界面外观以及强有力的技术支持。虽然二者的价值主张相似，但有很多方面仍存在不少差别。双方都能帮助开发人员更快、更轻松地构建并发布应用程序，但作为成熟度更高的框架选项，React Native 的社区规模更大；而 Flutter 则提供更多内置工具，可帮助用户减少对第三方工具的依赖。我之所以更倾向于 Flutter，当然是觉得它在很多方面比 React Native 的表现更好。在解释具体原因之前，咱们不妨先聊聊这些框架的基本情况，以及它们分别适合处理的应用项目类型。 React Native React Native 是由 Facebook 公司于 2015 年开发并发布的。这是一套开源跨平台应用程序开发框架，适用于移动及 Web 等多种应用程序项目。自 React Native 以来

Basic flutter bluetooth questions

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问题 I'm undertaking a new project involving flutter and bluetooth. For this I read a bit about it and tried a test project, but I still have questions I find no easy answer for. Firstly, BLE vs Bluetooth. BLE is nothing else than Bluetooth version 4, mostly used in IoT applications. It can run in mobile phones, but is there any compatibility issues? AKA, can a BLE device comunicate with a bluetooth device or do they both need to be using the same bluetooth version? This question comes from

Issue with PersistentBottomNavBar: MediaQuery.of(context)

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问题 I have some issues with PersistentBottomNavBar package in my Flutter App. It gives me an error with MediaQuery.of(context) message: 'it called with a context that does not contain a MediaQuery'. I can't imagine what's going on here. Maybe it's because I'm using persistentBottomNavbar inside MultiProvider widget? I've tried to get rid of MultiProvider with MaterialApp widgets and return only PersistentTabView widget as a build widget. But it couldn't help me. The code I have: import 'package

Flutter - PlatformException : error, Invalid document reference. Document references must have an even number of segments, but users has 1, null

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问题 I wanted to get my users data from cloud firestore. It worked first but now it is raising a error. "PlatformException (PlatformException(error, Invalid document reference. Document references must have an even number of segments, but users has 1, null))" String name = "", email = "", pnumber = "", imgUrl = "", bio = "", posted = "", applied = "", rating = "", saved = ""; String url; final formKey = new GlobalKey<FormState>(); final databaseReference = Firestore.instance; String uID; @override

Flutter - PlatformException : error, Invalid document reference. Document references must have an even number of segments, but users has 1, null

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Flutter: The instance member'stars' can't be accessed in an initializer. Error

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问题 https://flutter.dev/docs/development/ui/layout#nesting-rows-and-columns When I was looking at the linked page above import 'package:flutter/material.dart'; import 'package:flutter/rendering.dart' show debugPaintSizeEnabled; void main() { debugPaintSizeEnabled = true; // Remove to suppress visual layout runApp(MyApp()); } class MyApp extends StatelessWidget { Widget stars=Row( mainAxisSize: MainAxisSize.min, children: [ Icon(Icons.star, color: Colors.green[500]), Icon(Icons.star, color: Colors