dart

问题 I have a record class to parse objects coming from Firestore. A stripped down version of my class looks like: class BusinessRecord { BusinessRecord.fromMap(Map<String, dynamic> map, {this.reference}) : assert(map['name'] != null), name = map['name'] as String, categories = map['categories'] as List<String>; BusinessRecord.fromSnapshot(DocumentSnapshot snapshot) : this.fromMap(snapshot.data, reference: snapshot.reference); final String name; final DocumentReference reference; final List<String

问题 Edit: I am using the IOS simulator, the following issue may not be persistent across all platforms. I am under the impression that when creating a RaisedButton, it is possible to change the color of the button when the cursor hovers over the button. However this does not appear to be the case. // Create button RaisedButton( onPressed: () {}, color: Colors.redButtonBackgroundColo textColor: Colors.white, disabledColor: Colors.disabledRedButtonBackgroundColor, disabledTextColor: Colors.white,

问题 Edit: I am using the IOS simulator, the following issue may not be persistent across all platforms. I am under the impression that when creating a RaisedButton, it is possible to change the color of the button when the cursor hovers over the button. However this does not appear to be the case. // Create button RaisedButton( onPressed: () {}, color: Colors.redButtonBackgroundColo textColor: Colors.white, disabledColor: Colors.disabledRedButtonBackgroundColor, disabledTextColor: Colors.white,

问题 I'd like to know how I could get all dates of a given month and year added into a Dynamic List in flutter? The idea is to display this information in a data table. How can I put all dates (for a given month) in a List? List myListOfDates = Dates(may2020).format(day.month.year) How can I produce this? Thanks 回答1: If I understand your situation right, what I have stipulated is to find all the dates of the particular specified month. ALGORITHM Take the input in a month number and year, and pass

问题 I'd like to know how I could get all dates of a given month and year added into a Dynamic List in flutter? The idea is to display this information in a data table. How can I put all dates (for a given month) in a List? List myListOfDates = Dates(may2020).format(day.month.year) How can I produce this? Thanks 回答1: If I understand your situation right, what I have stipulated is to find all the dates of the particular specified month. ALGORITHM Take the input in a month number and year, and pass

问题 Im very new to flutter and dart so this might be a basic question. However, what I would like to know is how to implement a swipe to delete method in a listview to delete data from firestore too. I tried using the Dissmissible function but i dont understand how to display the list and I cant seem to understand how to remove the selected data as well. This here is my dart code Widget build(BuildContext context) { return new Scaffold( resizeToAvoidBottomPadding: false, appBar: new AppBar(

问题 This is the new assignment operator I see in Flutter source code: splashFactory ??= InkSplash.splashFactory; textSelectionColor ??= isDark ? accentColor : primarySwatch[200]; what's the meaning of this assignment operator? example in Flutter source code 回答1: ??= is a new null-aware operators. Specifically ??= is null-aware assignment operator. ?? if null operator. expr1 ?? expr2 evaluates to expr1 if not null , otherwise expr2 . ??= null-aware assignment. v ??= expr causes v to be assigned

问题 This is the new assignment operator I see in Flutter source code: splashFactory ??= InkSplash.splashFactory; textSelectionColor ??= isDark ? accentColor : primarySwatch[200]; what's the meaning of this assignment operator? example in Flutter source code 回答1: ??= is a new null-aware operators. Specifically ??= is null-aware assignment operator. ?? if null operator. expr1 ?? expr2 evaluates to expr1 if not null , otherwise expr2 . ??= null-aware assignment. v ??= expr causes v to be assigned

问题 I have two Containers of height 250 inside Column widget. There is no any other widget present between this two Container widget but still I can see very little space between two containers. Here's my code... import 'package:flutter/material.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', home: Example(), ); } } class Example extends StatelessWidget { @override Widget build

问题 Flutter log prints thousands of verbose/spam logs. I am trying to debug a complex app but flutter printing so much verbose that it is difficult for me to find things which i am printing myself. Is there any way to disable Verbose? Something like: Logger.level.disable('verbose') My platform: Doctor summary (to see all details, run flutter doctor -v): [√] Flutter (Channel stable, v1.12.13+hotfix.8, on Microsoft Windows [Version 10.0.18362.657], locale en-US) [√] Android toolchain - develop for