Flutter Textformfield Focused Underline Border Thickness Customization

In this tutorial, we’ll learn how to properly customize Flutter textformfield focused underline border thickness by using practical Flutter code examples.

Outline

1. Introduction: Flutter Textformfield Focused Underline Border Thickness
2. Default Flutter Textformfield Focused Underline Border Thickness
3. Change Flutter Textformfield Focused Underline Border Thickness (Multiple Examples)
4. Custom Flutter Textformfield Focused Underline Border Thickness Source Code
5. Conclusion

Introduction: Flutter Textformfield Focused Underline Border Thickness

It specifies the height/thickness of Flutter textformfield focused underline border. Focused border is visible when the textformfield is tapped/focused. We’ll first see the default underline focused border thickness. After that, we’ll customize it practically.

Default Flutter Textformfield Focused Underline Border Thickness

For that, we’ve to implement a simple Flutter textformfield widget. It comes with an underline border having default thickness. See below code:

TextFormField()

We can see default Flutter textformfield focused underline border thickness in the above given image. Let’s now customize it.

Change Flutter Textformfield Focused Underline Border Thickness (Multiple Examples)

• For that, we’ve to use the decoration constructor of Flutter textformfield and pass it input decoration.
• After that, we’ve to pass underline input border to its focused border constructor.
• Now we’ve to pass border side widget to its border side constructor.
• Finally, by using its width constructor, we can easily change Flutter textformfield focused underline border thickness. This constructor takes a double(decimal) value but passing it an integer will also work just fine.
• For demonstration, we’ll use multiple examples to show how it works. See below examples:

Example 1

focusedBorder:
       UnderlineInputBorder(borderSide: BorderSide(width: .1))

TextFormField(
       decoration: InputDecoration(
          focusedBorder:
             UnderlineInputBorder(
               borderSide: BorderSide(width: 5)
                      )),
          )

So this is how we can properly customize Flutter textformfield focused underline border thickness. Hope you like this post.

Custom Flutter Textformfield Focused Underline Border Thickness Source Code

import 'package:flutter/material.dart';
void main() {
  runApp(const MyApp());
}
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Homepage(),
    );
  }
}
class Homepage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
        child: Scaffold(
            body: Center(
      child: Padding(
          padding: EdgeInsets.symmetric(horizontal: 40),
          child: TextFormField(
            decoration: InputDecoration(
                focusedBorder:
                    UnderlineInputBorder(borderSide: BorderSide(width: 5)),
          )),
    )));
  }
}