dart

How to convert Image to File in Flutter?

由 喜你入骨 提交于 2021-02-07 20:09:07
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

Flutter : How to Debug which widgets re-rendered on state change

由 廉价感情. 提交于 2021-02-07 19:56:37
问题 I am using Redux with Flutter for state management. Whenever I dispatch an action, I want to know which widgets were re-rendered. Is there any way of doing it? 回答1: In flutter, whenever one widget update ; the whole widget tree repaint. So... no. But you can also introduce "repaint boundaries" manually by inserting in your tree a RepaintBoundary widget. This explicitly tells flutter to create a new painting layer for it's child (which implies memory cache). So that whenever that child updates

Flutter : How to Debug which widgets re-rendered on state change

由 杀马特。学长 韩版系。学妹 提交于 2021-02-07 19:56:25
问题 I am using Redux with Flutter for state management. Whenever I dispatch an action, I want to know which widgets were re-rendered. Is there any way of doing it? 回答1: In flutter, whenever one widget update ; the whole widget tree repaint. So... no. But you can also introduce "repaint boundaries" manually by inserting in your tree a RepaintBoundary widget. This explicitly tells flutter to create a new painting layer for it's child (which implies memory cache). So that whenever that child updates

Flutter: How to insert text in middle of text field text

由 人盡茶涼 提交于 2021-02-07 19:32:30
问题 I have a text field in flutter and an emoji picker button. On selecting an emoji I need to insert it at the current cursor position. How can I achieve this? Currently using TextEditingController I'm only able to append the emoji. I'm not able to get the current cursor offset. emojiPicker() { return EmojiPicker( rows: 3, columns: 7, recommendKeywords: null, indicatorColor: flujoAccentColor, onEmojiSelected: (emoji, category) { print(emoji); _messageInputController.text =

The superclass 'Bloc<xxx, xxx>' doesn't have a zero argument constructor in dart

由 安稳与你 提交于 2021-02-07 18:46:43
问题 I am a beginner in Dart language development. I try to create a sample flutter application BLOC pattern inspired by this GitHub repo, but I got some error message related to the class inheritance. I am already familiar with the inheritance and superclass and subclass programming in the dot net C# language. But in the case of the dart, I need some advice. Here is my code: class UserRegBloc extends Bloc<UserRegEvent, UserRegState> { UserRepository userRepository; UserRegBloc({@required

The superclass 'Bloc<xxx, xxx>' doesn't have a zero argument constructor in dart

由 China☆狼群 提交于 2021-02-07 18:46:22
问题 I am a beginner in Dart language development. I try to create a sample flutter application BLOC pattern inspired by this GitHub repo, but I got some error message related to the class inheritance. I am already familiar with the inheritance and superclass and subclass programming in the dot net C# language. But in the case of the dart, I need some advice. Here is my code: class UserRegBloc extends Bloc<UserRegEvent, UserRegState> { UserRepository userRepository; UserRegBloc({@required

初见Flutter

由 余生长醉 提交于 2021-02-07 17:07:05
前言 2019年身边所有的朋友都在学习Flutter，我也加入这个浪潮中，简单接触Flutter后，依然离不开了。 最新版本： Flutter 1.0 已发布 Flutter是谷歌的移动UI框架，可以快速在iOS和Android上构建高质量的原生用户界面。 Flutter可以与现有的代码一起工作。在全世界，Flutter正在被越来越多的开发者和组织使用，并且Flutter是完全免费、开源的。 三大特点 快速开发 毫秒级的热重载，修改后，您的应用界面会立即更新。使用丰富的、完全可定制的widget在几分钟内构建原生界面。 Flutter的热重载可帮助您快速地进行测试、构建UI、添加功能并更快地修复错误。在iOS和Android模拟器或真机上可以在亚秒内重载，并且不会丢失状态。 富有表现力和灵活的UI 快速发布聚焦于原生体验的功能。分层的架构允许您完全自定义，从而实现难以置信的快速渲染和富有表现力、灵活的设计。 使用Flutter内置美丽的Material Design和Cupertino（iOS风格）widget、丰富的motion API、平滑而自然的滑动效果和平台感知，为您的用户带来全新体验。 原生性能 Flutter包含了许多核心的widget，如滚动、导航、图标和字体等，这些都可以在iOS和Android上达到原生应用一样的性能。 Flutter 是

what's the different between full path and relative path in dart

由 [亡魂溺海] 提交于 2021-02-07 14:28:34
问题 I develop a flutter app, define serveral models in 'model' package. Then I declare a class Example in 'model' for example. model/example.dart class Example { @override String toString() { return 'class example'; } } test_a.dart import 'package:example/model/example.dart' Example testA() { return Example() } test.dart import 'model/example.dart' import 'test_a.dart' test() { Example example = testA(); if (example is Example) { print('this class is Example'); } else { print('$example'); } } I

what's the different between full path and relative path in dart

由 雨燕双飞 提交于 2021-02-07 14:24:12
问题 I develop a flutter app, define serveral models in 'model' package. Then I declare a class Example in 'model' for example. model/example.dart class Example { @override String toString() { return 'class example'; } } test_a.dart import 'package:example/model/example.dart' Example testA() { return Example() } test.dart import 'model/example.dart' import 'test_a.dart' test() { Example example = testA(); if (example is Example) { print('this class is Example'); } else { print('$example'); } } I

flutter error Invalid `Podfile` file: no implicit conversion of nil into String. ive searched through discussions but I cant seem to fix the issue

由 末鹿安然 提交于 2021-02-07 13:44:06
问题 This is the error I am receiving. I tried flutter clean and changing the syntax of some lines but im new to dart and flutter so im not really sure. I reinstalled cocoa pods and ruby as well but Im receiving the same error. I also made sure to update ruby to the latest version. [!] Invalid `Podfile` file: no implicit conversion of nil into String. # from /Users/(name)/Downloads/Projects/doctor_consultation_app/ios/Podfile:57 # ------------------------------------------- # unless File.exist?
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