dart

How to Move bottomsheet along with keyboard which has textfield(autofocused is true)?

To fix this issue Add isScrollControlled = true to BottomSheetDialog it’ll allow the bottom sheet to take the full required height which gives more insurance that the keyboard does not cover TextField. Add Keyboard padding using MediaQuery.of(context).viewInsets.bottom Note If your BottomSheetModel is Column make sure you add mainAxisSize: MainAxisSize.min, otherwise the sheet will cover the … Read more

How to make an AlertDialog in Flutter?

One Button showAlertDialog(BuildContext context) { // set up the button Widget okButton = TextButton( child: Text(“OK”), onPressed: () { }, ); // set up the AlertDialog AlertDialog alert = AlertDialog( title: Text(“My title”), content: Text(“This is my message.”), actions: [ okButton, ], ); // show the dialog showDialog( context: context, builder: (BuildContext context) { return … Read more

Error: The argument type ‘String?’ can’t be assigned to the parameter type ‘String’ because ‘String?’ is nullable and ‘String’ isn’t [duplicate]

The error is caused by the null safety feature in Dart, see https://dart.dev/null-safety. The result of method stdin.readLineSync() is String?, i.e. it may be a String, or it may be null. The method int.parse() requires a (non-null) String. You should check that the user gave some input, then you can assert that the value is … Read more

How do I run a reoccurring function, in Dart?

You can use the Timer class to schedule one-shot and repeating functions. Repeating Here is how you run a repeating function: import ‘dart:async’; main() { const oneSec = Duration(seconds:1); Timer.periodic(oneSec, (Timer t) => print(‘hi!’)); } The Timer takes two arguments, a duration and a function to run. The duration must be an instance of Duration. … Read more

void Function(int) isn’t a valid override of void Function(dynamic)

void Function(int x) normally isn’t a valid override of void Function(dynamic x) because the int version is not substitutable for the dynamic version. What are the allowed inputs to Parent<dynamic>.method? Anything. What are the allowed inputs to Child.method? Just ints. Such an override therefore could violate the contract of Parent<dynamic>‘s interface. (For example, what if … Read more

Flutter: Retrieving top-level state from child returns null

TDLR: imports file only using import ‘package:myApp/path/myFile.dart’; Never with import ‘./myFile.dart’; This is due to how dart resolves imports. You may have a single source file, but during builds, there is some kind of duplicates. Let’s say you’re working on ‘myApp’. To import a file, you could do both : import ‘relativePath/myFile.dart’ import ‘package:myApp/path2/myFile.dart’ You’d … Read more

Displaying text with Emojis on Flutter

The Problem As of now, unfortunately, Flutter uses the default Emojis supported on a given platform. Therefore, when building a cross-platform app you may face issues of Emojis showing on certain devices and not on others. The Solution The solution I settled for is to use a custom Emoji font such as Emoji One and … Read more

Creating function with variable number of arguments or parameters in Dart

You can’t do that for now. I don’t really know if varargs will come back – they were there some times ago but have been removed. However it is possible to emulate varargs with Emulating functions. See the below code snippet. typedef OnCall = dynamic Function(List arguments); class VarargsFunction { VarargsFunction(this._onCall); final OnCall _onCall; noSuchMethod(Invocation … Read more