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How to Pick files and Images for upload with flutter web

Using dart:html package directly in Flutter is not recommended. Instead, use this package: https://pub.dev/packages/file_picker. Example of how to use in Flutter Web: class FileUploadButton extends StatelessWidget { @override Widget build(BuildContext context) { return RaisedButton( child: Text(‘UPLOAD FILE’), onPressed: () async { var picked = await FilePicker.platform.pickFiles(); if (picked != null) { print(picked.files.first.name); } }, ); … Read more

How to convert Flutter color to string and back to a color

In Dart the as operator doesn’t allow you to change the actual structure of an Object, it just allows you to provide a hint that an object might have a more specific type. For example, if you had a dog and an animal class you could use as to specify that your animal is actually … Read more

how to place a listview inside a SingleChildScrollView but prevent them from scrolling separately?

You could use your first widget-tree and apply the following changes: In every ListView and GridView set shrinkWrap: true. This fixes the error message you were getting. In every ListView and GridView set physics: NeverScrollableScrollPhysics(). This disables the scroll on them and new you can only scroll on the SingleChildScrollView

How do I build different versions of my Flutter app for qa/dev/prod?

Building on Seth’s idea, here’s an example that sets up a global representing the BuildEnvironment named env. env.dart import ‘package:meta/meta.dart’; enum BuildFlavor { production, development, staging } BuildEnvironment get env => _env; BuildEnvironment _env; class BuildEnvironment { /// The backend server. final String baseUrl; final BuildFlavor flavor; BuildEnvironment._init({this.flavor, this.baseUrl}); /// Sets up the top-level [env] … Read more

Async/Await feature in Dart 1.8

Update 2 The most recent nightly build also supports async* void main() { generate().listen((i) => print(i)); } Stream<int> generate () async* { int i = 0; for(int i = 0; i < 100; i++) { yield ++i; } } Update yield and yield* in a method marked sync* (returning an Iterable) are already supported in … Read more

forEach vs for in: Different Behavior When Calling a Method

Although there is a prefer_foreach lint, that recommendation is specifically for cases where you can use it with a tear-off (a reference to an existing function). Effective Dart recommends against using Iterable.forEach with anything else, and there is a corresponding avoid_function_literals_in_foreach_calls lint to enforce it. Except for those simple cases where the callback is a … Read more

How to achieve precompiler directive like functionality

I see two possibilities (haven’t tried any of these myself yet) one is to use a transformer (see also Pass custom parameters to a dart application when using pub serve to run it) or Compile-time dead code elimination with dart2js Recently a feature should have been added that pub build allows adding an environment variables … Read more

Flutter Load Image from Firebase Storage

To view the images inside your storage, what you need is the name of the file in the storage. Once you’ve the file name for the specific image you need. In my case if i want the testimage to be loaded, final ref = FirebaseStorage.instance.ref().child(‘testimage’); // no need of the file extension, the name will … Read more

When I select a Textfield the keyboard moves over it

Compose an animation and move your TextField container up when a TextField gets focus. For learning about composing animations refer to: Composing Animations and Chaining Animations in Dart’s Flutter Framework Use Flutter’s FocusNode to detect the focus on a TextField Edit: Here I’ve written an example that does exactly what you want: import ‘package:flutter/material.dart’; void … Read more

how can we use superscript and subscript text in flutter Text or RichText

You need to use Unicode. Here is the Unicode got from this answer: unicode_map = { # superscript subscript ‘0’ : (‘\u2070’, ‘\u2080’ ), ‘1’ : (‘\u00B9’, ‘\u2081’ ), ‘2’ : (‘\u00B2’, ‘\u2082’ ), ‘3’ : (‘\u00B3’, ‘\u2083’ ), ‘4’ : (‘\u2074’, ‘\u2084’ ), ‘5’ : (‘\u2075’, ‘\u2085’ ), ‘6’ : (‘\u2076’, ‘\u2086’ ), ‘7’ … Read more