Answering The Frequently Asked Questions in Flutter Development #2

Answering The Frequently Asked Questions in Flutter Development #2

  • This is Part #2 of the Flutter FAQs series. In this series, I'm compiling all of the frequently asked questions that Flutter developers encounter while building an app.
  • So let's get this party started.

1. How to Auto-Complete TextField

  • Filling out a form in an application is really tedious. We don't want to retype the same information in the form every time, such as Name, Email, Address, Phone Number, and so on.
  • So, as developers, we can auto-suggest the user when they are on a specific text field.
  • To accomplish this, simply supply an array of AutofillHints into the TextField widget's autofillHints attribute.
  • TextField(
      decoration: InputDecoration(hintText: "Username")
      autofillHints: [] // or, AutofillHints.postalAddress...

2. How to Refresh/Update AlertDialog

  • If you've ever tried to update the state of dialogue by clicking a button within it, you'll notice that the state doesn't update. It's because when you call setState, the parent widget's build is updated. However, in our case, we opened a separate dialogue that is unrelated to the build approach. That is why it is not being updated.
  • To update the dialogue, enclose your AlertDialog within the StatefulBuilder widget.
  • You will gain access to the setState method, which will be used to update the state of the dialogue.
  • Use StatefulBuilder to use setState within Dialog and just update Widgets within it.
  • showDialog(
       context: context,
       builder: (context) {
         return StatefulBuilder(
              builder: (context, setState) {
                   return AlertDialog(

3. How to call async function inside initState

  • Often, when the screen first loads, we want to call a function. And we call it in initState because it is only called once when the screen loads. This is sufficient for a standard solution. However, if you execute an async function within it, initState will throw an error.
  • To resolve this issue, just build your async function outside of initState and call it inside initState as seen below:
  • @override
    void initState() {
    Future<void> loadDataFromAPI() async {    // ....  }

4. How to preload Image

  • Sometimes, we'd like to preload certain photos before the screen load. On the first page, for example, we want a background image.
  • However, retrieving that image from assets or the internet will take some time before it loads. Because the image only flashes/blinks after image fetch, this could be a negative user experience.
  • You can use the precacheImage method in the initState to begin loading an image before your page is constructed.
  • @override
    void initState() {
      precacheImage(new AssetImage('...')); // or NetworkImage('...'), etc.

5. How to hide StatusBar

  • By default, the Status bar is visible as shown in the below image:
  • statusbar.png
  • If you want to hide it for some reason then simply paste the below code in the main method.
  • import 'package:flutter/services.dart';
    void main(){
  • statusbar2.png

Wrapping Up

  • I hope you found this article to be beneficial. If you have any questions related to Flutter, please leave them in the comments. I will try my best to answer it.
  • Thank you for spending time reading this article. See you in the next article. So, until then...
  • PeaceOutImOutGIF.gif

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