dart

Flutter: Timer can not stop

由 爱⌒轻易说出口 提交于 2021-01-07 01:31:31
问题 My code is below. I try to close this timer. timer could not close. What can I do to close this timer? I need help immediatly. Timer timerHttp; @override void initState() { timerHttp = Timer.periodic(new Duration(seconds: 10), (timerHttp) async { print("girdi yine asdadasd"); final response = await http.get( "http://xxxxxxxxxxxxxxxxxxxxxxxxx", ); if (response.statusCode == 200) { setState(() { var responseJson = json.decode(response.body); cm100Datas = responseJson; saat = []; l1voltState = [

Flutter: Lazy Load data from firestore

由 醉酒当歌 提交于 2021-01-07 01:21:17
问题 Note: I have already seen answers on Lazy Load of ListView but those are for custom API not firestore database! I have a books summary app, App fetches data from my Firebase/Firestore database and then display it using a ListView.builder which is wrapped inside a StreamBuilder . Now, I want to fetch data lazily, I mean as the user scrolls through the List the required data gets loaded rather than loading data at once and then displaying it lazily. //The Widget used to display data: Widget

Flutter listview builder Scroll controller listener not firing inside list view?

由 一个人想着一个人 提交于 2021-01-06 05:01:11
问题 I have a listview builder widget inside another list view. Inner listview listener is not firing when scrolling position reaches to its end. initState() { super.initState(); _scrollController.addListener(() { if (_scrollController.position.maxScrollExtent == _scrollController.position.pixels) {function();} } Container( child: Listview( children: <Widget>[ Container(), ListView.builder( controller: _scrollController, physics: NeverScrollableScrollPhysics(), shrinkWrap: true, itemCount: list

Flutter listview builder Scroll controller listener not firing inside list view?

由 大憨熊 提交于 2021-01-06 05:00:11
问题 I have a listview builder widget inside another list view. Inner listview listener is not firing when scrolling position reaches to its end. initState() { super.initState(); _scrollController.addListener(() { if (_scrollController.position.maxScrollExtent == _scrollController.position.pixels) {function();} } Container( child: Listview( children: <Widget>[ Container(), ListView.builder( controller: _scrollController, physics: NeverScrollableScrollPhysics(), shrinkWrap: true, itemCount: list

Is it possible to have multiple type constaints on a generic type?

由 只愿长相守 提交于 2021-01-06 04:29:08
问题 In dart you can do class Preference<T extends int> to define a type constraint. But is there a way to define multiple constrains? I tried class Preference<T extends int, String> But an error get's thrown when I try to pass a argument of type T to a function that excepts a String saying The argument type 'T' can't be assigned to the parameter type 'String' 回答1: No, Dart type parameters can only have a single constraint. There is no workaround. 来源： https://stackoverflow.com/questions/61820181

Flutter支持Web开发了！

由 你。 提交于 2021-01-05 18:05:24
Flutter作为一个可移植的UI框架，已经支持现代Web应用开发了！我们很开心已经发布了SDK预览版，这样你可以在Web浏览器里直接运行你的Flutter UI代码。 原文链接： Flutter Web - 目标全平台开发的Flutter再下一城！- 汇智网 Flutter Web的目标 从去年Beta版发布以来，客户们已经使用Flutter来创建可以运行在iOS和Android上的移动应用了。但是，Flutter是以可移植的UI工具集构架的，它还可以运行在其他环境下，例如Windows、Mac、Fuchsia甚至Raspberry Pi。 由于Flutter是使用Dart构建的，它针对原生机器码和JavaScript都包含了生产级的编译器，因此我们有了一个坚实的基础。接下来的挑战在于需要使用web平台的对等单元来替换基于Skia的图形引擎和文本渲染器。 要正确地实现这一点，我们需要提供： 60帧/秒快速平滑动画的性能 与其他平台一致的行为和视觉感受 可以与当前开发模式集成的高效的开发者工具 在所有现代浏览器上对核心web特性的支持 虽然用于Web的Flutter还在开发中，在上述几个方面都还有很多工作要进行，不过我们已经可以和大家分享一个预览版了，你可以尝试以下，期待你的反馈！ Flutter Web总体架构 Flutter

Flutter web开发之跳转到外部网站

由 ☆樱花仙子☆ 提交于 2021-01-05 18:05:07
在Flutter Web开发中,有时候需要跳转到网站, 可以通过url_launcher这个第三方库实现. 代码示例 首先引入依赖 url_launcher: ^5.4.2 业务代码: import 'package:url_launcher/url_launcher.dart'; //定义方法 _launchURL(url) async { if (await canLaunch(url)) { await launch(url); } else { throw 'Could not launch $url'; } } //跳转 _launchURL("https://www.testerhome.com"); Flutter 写的app, 需要源码可以私信~~ 简繁火星字体转换 哄女友神器 号码测吉凶 电视节目直播表 最好的笔记软件 https://www.wolai.com/signup?invitation=6Z8Z3BP 来源： oschina 链接： https://my.oschina.net/u/4197015/blog/4878971

Flutter web开发之跳转到外部网站

由 只谈情不闲聊 提交于 2021-01-05 16:48:33
在Flutter Web开发中,有时候需要跳转到网站, 可以通过url_launcher这个第三方库实现. 代码示例 首先引入依赖 url_launcher: ^5.4.2 业务代码: import 'package:url_launcher/url_launcher.dart'; //定义方法 _launchURL(url) async { if (await canLaunch(url)) { await launch(url); } else { throw 'Could not launch $url'; } } //跳转 _launchURL("https://www.testerhome.com"); Flutter 写的app, 需要源码可以私信~~ 简繁火星字体转换 哄女友神器 号码测吉凶 电视节目直播表 最好的笔记软件 来源： oschina 链接： https://my.oschina.net/u/4197015/blog/4879019

Upload image to Azure blob using Flutter (iOS/Android)

由 半腔热情 提交于 2021-01-05 11:25:53
问题 How can we upload images(.jpg, .png) to Azure blob storage. Not getting any insight to start with. If you have used example would love to see and try if that is the way to do, any working example/url would help get started with Here is i am trying to upload .jpg file and getting 400 error, image.forEach((element) async { ImageDetailsUpload result = ImageDetailsUpload.fromJson(element); var postUri = Uri.parse('$url/${result.fileName}?$code'); //Azure blob url var request = new http

Items state changes when scrolling in listview

由 久未见 提交于 2021-01-05 11:01:11
问题 I have list view, which contains ExpansionPanelList and each ExpansionPanel has a button .. checking/unchecking it will change a color. When I for example uncheck the first three on the list, then scroll down to the end of the list, then came up again I see the unchecked items being checked again. Here's my code: new Expanded( child: new ListView( padding: EdgeInsets.only( right: 20.0, left: 20.0 /*, bottom: 20.0*/), children: interestsMap['interests'] .map<Widget>((i) => new InterestsItem
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