dart

问题 I'm upgrading a personal package that is based on the Flutter framework. I noticed here in the Flutter Text widget source code that there is a null check: if (textSpan != null) { properties.add(textSpan!.toDiagnosticsNode(name: 'textSpan', style: DiagnosticsTreeStyle.transition)); } However, textSpan! is still using the ! operator. Shouldn't textSpan be promoted to a non-nullable type without having to use the ! operator? However, trying to remove the operator gives the following error: An

问题 I'm upgrading a personal package that is based on the Flutter framework. I noticed here in the Flutter Text widget source code that there is a null check: if (textSpan != null) { properties.add(textSpan!.toDiagnosticsNode(name: 'textSpan', style: DiagnosticsTreeStyle.transition)); } However, textSpan! is still using the ! operator. Shouldn't textSpan be promoted to a non-nullable type without having to use the ! operator? However, trying to remove the operator gives the following error: An

问题 Summary: I'm very new on Flutter and Dart and I'm trying to create a kind of exercise for myself about how to perform a login and protect my app pages . My goal asking this question is to understand about the best practices to protect, login and logout from my Flutter app. I've performed a lot of research about the architectures and patterns available and I've read about the BLoC pattern but I still have difficult to understand how it works. If someone could help me with some explanation

问题 In my Flutter project, I want to schedule an alarm on a specific time of a day or just trigger the built in alarm in my phone on that particular time. For that purpose, I have integrated one plugin from Flutter - https://pub.dev/packages/android_alarm_manager#-example-tab- And then I followed exactly the example given in that documentation and added all the permissions in Android Manifest file. After running this project it shows like below- It is showing one button to shot one alarm but it

问题 I was using dialogBackgroundColor property still the color was not changing. Can anyone tell me how to change the background color of the dialog? 回答1: You can now use backgroundColor property of AlertDialog to change the color. AlertDialog( backgroundColor: Colors.orange, ... ) 回答2: You need to wrap your Dialog in a Builder like this. After that dialogBackgroundColor will have an effect. Theme( data: ThemeData(dialogBackgroundColor: Colors.orange), child: Builder( builder: (context) { return

问题 I was using dialogBackgroundColor property still the color was not changing. Can anyone tell me how to change the background color of the dialog? 回答1: You can now use backgroundColor property of AlertDialog to change the color. AlertDialog( backgroundColor: Colors.orange, ... ) 回答2: You need to wrap your Dialog in a Builder like this. After that dialogBackgroundColor will have an effect. Theme( data: ThemeData(dialogBackgroundColor: Colors.orange), child: Builder( builder: (context) { return

问题 This is the sample code using rootName but here I am not able to use MaterialPageRoute to get the fullScreenDialog property. class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( initialRoute: '/', routes: { '/': (context) => MyHomePage(), '/under-development': (context) => UnderDevelopment(), '/profile1': (context) => Profile1() }, title: appName, debugShowCheckedModeBanner: false, theme: ThemeData( primaryColor: primaryColor, accentColor:

问题 I'm trying to use DefaultTabController in the middle of some widgets. So my TabBar could not be in AppBar and has to be down some widgets. So my problem is when I use TabBarView it crashes... So here's an example of Flutter sample but no found how to do it without Scaffold . final List<Tab> myTabs = <Tab>[ Tab(text: 'LEFT'), Tab(text: 'RIGHT')]; Code DefaultTabController( length: myTabs.length, child: Scaffold( appBar: TabBar( tabs: myTabs, ), body: TabBarView( children: myTabs.map((Tab tab)

问题 I'm trying to use DefaultTabController in the middle of some widgets. So my TabBar could not be in AppBar and has to be down some widgets. So my problem is when I use TabBarView it crashes... So here's an example of Flutter sample but no found how to do it without Scaffold . final List<Tab> myTabs = <Tab>[ Tab(text: 'LEFT'), Tab(text: 'RIGHT')]; Code DefaultTabController( length: myTabs.length, child: Scaffold( appBar: TabBar( tabs: myTabs, ), body: TabBarView( children: myTabs.map((Tab tab)

问题 I'm trying to use DefaultTabController in the middle of some widgets. So my TabBar could not be in AppBar and has to be down some widgets. So my problem is when I use TabBarView it crashes... So here's an example of Flutter sample but no found how to do it without Scaffold . final List<Tab> myTabs = <Tab>[ Tab(text: 'LEFT'), Tab(text: 'RIGHT')]; Code DefaultTabController( length: myTabs.length, child: Scaffold( appBar: TabBar( tabs: myTabs, ), body: TabBarView( children: myTabs.map((Tab tab)