dart

问题 I know that this keyword should be used in some custom library, but when I dropped it, nothing happened (at least I didn't notice anything), imports still worked fine, private members remained private. Could somebody explain what "library" keyword in Dart do? 回答1: update 2018-03-05 For a while now, part of accepts a URI, which reduces the need of library to a few edge cases. update 2015-11-27 With a recent change, two imported nameless libraries don't produce a warning anymore. The plan is to

问题 I'm trying to create a button with these effects: Currently I have a rounded flat button like this: RaisedButton( color: Color(0xFFA93EF0), shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(30.0), ), How can I apply such effects to make it look 3D? I don't know the name of this effect but it looks like glass 回答1: Final Output: We can achieve this look using ClipPath and CustomClipper , It will be a little hard to comprehend the code below at first if you are not accustomed to

问题 I'm trying to create a button with these effects: Currently I have a rounded flat button like this: RaisedButton( color: Color(0xFFA93EF0), shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(30.0), ), How can I apply such effects to make it look 3D? I don't know the name of this effect but it looks like glass 回答1: Final Output: We can achieve this look using ClipPath and CustomClipper , It will be a little hard to comprehend the code below at first if you are not accustomed to

问题 I'm trying to create a button with these effects: Currently I have a rounded flat button like this: RaisedButton( color: Color(0xFFA93EF0), shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(30.0), ), How can I apply such effects to make it look 3D? I don't know the name of this effect but it looks like glass 回答1: Final Output: We can achieve this look using ClipPath and CustomClipper , It will be a little hard to comprehend the code below at first if you are not accustomed to

问题 I have a listview with some TextFields inside, I think that it will be cool to add the textfield once a user scrolls down, For example: We have 5 Elements in ListView after a user reaches the fifth element and continued scrolling down a new element is created. I couldn't find a solution for this task, I tried to check scrollposition for elements but unfortunately, I got an error flutter: Another exception was thrown: NoSuchMethodError: The getter 'position' was called on null. Here is the

问题 I have a listview with some TextFields inside, I think that it will be cool to add the textfield once a user scrolls down, For example: We have 5 Elements in ListView after a user reaches the fifth element and continued scrolling down a new element is created. I couldn't find a solution for this task, I tried to check scrollposition for elements but unfortunately, I got an error flutter: Another exception was thrown: NoSuchMethodError: The getter 'position' was called on null. Here is the

问题 I was looking into quite a few pages to learn how to best implement an app wide bloc (for authentication, user management and initialization). I did not find so much and for a beginner regarding this level of bloc patterns I found it hard to identify a reasonable one. The pattern by Didier Boelens explained here appears to be the most promising one. Is it still a sound pattern (it is from 2018) or did the bloc library evolve in the meantime or did other patterns proved better/easier? What

问题 I was looking into quite a few pages to learn how to best implement an app wide bloc (for authentication, user management and initialization). I did not find so much and for a beginner regarding this level of bloc patterns I found it hard to identify a reasonable one. The pattern by Didier Boelens explained here appears to be the most promising one. Is it still a sound pattern (it is from 2018) or did the bloc library evolve in the meantime or did other patterns proved better/easier? What

问题 Trying to navigate to a new screen using Navigator.push(), but it's not working. I have created a custom class to show AlertDialog and call the class with the object to show alertDialog _customerAlertDialog.showConfirmAlertDialog( context: context, title: "Login In", subTitle: "You need to login to purchase.", onTapResponse: (bool val) async { if (val) { /// close AlertDialog Navigator.of(context).pop(); Navigator.of(context).push(MaterialPageRoute(builder: (context) => LoginScreen())); print

问题 In my program, this error comes in my laptop only. I typed the exact code as of the tutorial, but in tutorial, it is working fine, and i am getting this error - Closure call with mismatched arguments: function '[]' Receiver: Closure: () => Map<String, dynamic> from Function 'data':. Tried calling: []("message") Found: []() => Map<String, dynamic> This is my code, in which error is coming. If you want full details of functions, you can comment it out, and i will provide you the same in