You could use https://github.com/slightfoot/flutter_after_layout which executes a function only one time after the layout is completed. Or just look at its implementation and add it to your code 🙂 Which is basically void initState() { super.initState(); WidgetsBinding.instance .addPostFrameCallback((_) => yourFunction(context)); }
Adding this two lines ListView.builder( scrollDirection: Axis.vertical, shrinkWrap: true, …
Do it like this: TextField( decoration: new InputDecoration.collapsed( hintText: ‘Username’ ), ), or if you need other stuff like icon, set the border with InputBorder.none InputDecoration( border: InputBorder.none, hintText: ‘Username’, ), ),
The build method is designed in such a way that it should be pure/without side effects. This is because many external factors can trigger a new widget build, such as: Route pop/push Screen resize, usually due to keyboard appearance or orientation change The parent widget recreated its child An InheritedWidget the widget depends on (Class.of(context) … Read more
I think you may want to introduce some helper functions to build your button as well as a Stateful widget along with some property to key off of. Use a StatefulWidget/State and create a variable to hold your condition (e.g. isButtonDisabled) Set this to true initially (if that’s what you desire) When rendering the button, … Read more
(I assume you’re using a Row because you want to put other widgets beside the TextField in the future.) The Row widget wants to determine the intrinsic size of its non-flexible children so it knows how much space that it has left for the flexible ones. However, TextField doesn’t have an intrinsic width; it only … Read more
UPDATE: Scaffold.of(context).showSnackBar is deprecated in Flutter 2.0.0 (stable) You can access the parent ScaffoldMessengerState using ScaffoldMessenger.of(context). Then do something like ScaffoldMessenger.of(context).showSnackBar(SnackBar( content: Text(“Sending Message”), )); Snackbars are the official “Toast” from material design. See Snackbars. Here is a fully working example: import ‘package:flutter/material.dart’; void main() { runApp(MyApp()); } class MyApp extends StatelessWidget { @override Widget … Read more
Use Random class from dart:math: import ‘dart:math’; main() { var rng = Random(); for (var i = 0; i < 10; i++) { print(rng.nextInt(100)); } } This code was tested with the Dart VM and dart2js, as of the time of this writing.
Edit: The Flutter team has now taken an official stance on the matter and stated that classes are preferable. See https://www.youtube.com/watch?v=IOyq-eTRhvo TL;DR: Prefer using classes over functions to make reusable widget-tree. EDIT: To make up for some misunderstanding: This is not about functions causing problems, but classes solving some. Flutter wouldn’t have StatelessWidget if a … Read more
To use recordObject in _RecordPageState, you have to just write widget.objectname like below class _RecordPageState extends State<RecordPage> { @override Widget build(BuildContext context) { ….. widget.recordObject ….. } }