我正在从firebase获取DropdownMenuItem的列表,如果我在构建中使用provider,它不会返回null,但是在initstate中,即使我设置了listen值,false也会返回null以下是错误消息:The getter 'first' was called on <em 浏览1提问于2021-01-06得票数1 1回答 在页面加载之前,我应该做些什么来异步初始化一些数据 ...
// Could do this in one line: Future.delayed(Duration.zero, this._getCategories);...
1)Unhandled Exception: setState() or markNeedsBuild() called during build. 大致意思:在构建期间调用setState()或markNeedsBuild()。 2)the framework builds parent widgets before children, which means a dirty descendant will always be built. Otherwise, the framework might not visit this widget during...
如果我将请求方法放在了initState方法中,异常如下: inheritFromWidgetOfExactType(_InheritedTheme) or inheritFromElement() was called before initState() completed. When an inherited widget changes, for example if the value of Theme.of() changes, its dependent widgets are rebuilt. If the dependent widge...
前面第二点我有说到我会在接口请求前弹出loading。如果我将请求方法放在了initState方法中,异常如下: inheritFromWidgetOfExactType(_InheritedTheme) or inheritFromElement() was called before initState() completed. When an inherited widget changes, for example if the value of Theme.of() changes, its depe...
{@overridevoidinitState() {super.initState();print('initState');WidgetsBinding.instance.addObserver(this); }@overridevoiddeactivate() {super.deactivate();//this method not called when user press android back button or quitprint('deactivate'); }@overridevoiddispose() {super.dispose();WidgetsBinding...
[ ] An Observatory debugger and profiler on Pixel 3a is available at: http://127.0.0.1:56917/ZnQHWAVVOYE=/ [ +20 ms] I/flutter (25520): initState() called [+5022 ms] I/flutter (25520): AppLifecycleState.inactive [ +66 ms] I/flutter (25520): AppLifecycleState.paused [ +596 ms...
void initState(){ WidgetsBinding.instance.addPostFrameCallback((_) { if (mounted) _animationController.forward(); }); } 1. 2. 3. 4. 5. 6. AnimationController有可能随着 State 一起dispose了,但是FrameCallback仍然会被执行,进而导致异常。
decode(response); //int len = data.length; //_cards[len]; setState(() { _cards = data['cards']; }); } @override void initState() { super.initState(); WidgetsBinding.instance.addPostFrameCallback((_) async { await readJson(); }); } @override Widget build(BuildContext context) ...
我们在Xcode中打开该项目的 iOS module,如下图所示: ?...在 AndroidManifest.xml 文件中添加如下代码: <provider android:name="vn.hunghd.flutterdownloader.DownloadedFileProvider...这里方便起见我选择在 initState()函数中初始化下载回调函数和对话框: @override void initState() { super.initState();...