Flutter Textfield Onchanged Explained With Example-Best Flutter Guide

In this article, I will be discussing Flutter textfield onChanged in detail, why it is used in Flutter textfield and how to use it. I will be implementing it step by step with proper example so you have a complete understanding of what Flutter textfield onChanged is and how to use it in Flutter textfield. Now let’s leave the boring part and start implementing Flutter textfield onChanged in Flutter app.

Outline

What is Flutter Textfield OnChanged?
Implementing Flutter Textfield OnChanged
Beautiful Flutter Textfield Source Code
Conclusion

What is Flutter Textfield OnChanged?

Flutter textfield onChanged is called whenever the user input or delete the input from the Flutter textfield. It is called for each input made to the Flutter textfield. It can be used to store the input in a variable. Don’t worry I will implement it using a proper example so you can understand everything about Flutter textfield onChanged.

Implementing Flutter Textfield OnChanged

To implement Flutter textfield onChanged, you have to use the onChanged constructor of the Flutter textfield. It takes a function with a string parameter, by using that string we can take the input value and store it in some variable.

TextField(
        onChanged: (value) {},
         )

As you can see in the above code, I have implemented the onChanged function. Let’s now implement our logic. I will make a variable string and pass that value in that string variable. Now whenever the user inputs something, it will be stored in that string variable and I will show that on top of the Flutter textfield. Let’s implement it:

Step 1

String inputValue = '';

I have implemented the string with input value name and passed it an empty string.

Step 2

 onChanged: (value) {
                setState(() {
                   inputValue = value;
                          });
                    },

Now in the Flutter textfield onChanged, I have passed the value to the string variable. You can use the print and pass the input value variable to it and try to input or delete input and you will see that this variable is successfully storing that value. But in our case, I have used the set state, the reason is I want to show the string in the screen.

Step 3

 Text(
       inputValue,
       style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
     )

As you can see that I have use Flutter text widget and have passed it the input value string, now whenever you entered or remove something for the Flutter textfield then it will be shown on the screen, the reason is that I have implemented this Flutter text widget above the Flutter textfield. Let’s see whether it works or not, see the below image for this:

You can see in that image that when we enter or delete an input then it is shown in the above Flutter text widget which is what we wanted to implement. If you want to learn more about Flutter textfield customization then click here.

Congrats, you have successfully implemented Flutter textfield onChanged. Now you have a complete understanding of how to use Flutter textfield onChanged and now you can use it in your Flutter app. Now as a treat, I have made a beautiful Flutter textfield design for you in which Flutter textfield onChanged is also implemented. The complete source code is given in the next section.

Beautiful Flutter Textfield Source Code

flutter textfield onchanged

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 StatefulWidget {
  @override
  State<Homepage> createState() => _HomepageState();
}
class _HomepageState extends State<Homepage> {
  String inputValue = '';
  @override
  Widget build(BuildContext context) {
    return SafeArea(
        child: Scaffold(
      body: Center(
          child: Padding(
              padding: EdgeInsets.symmetric(horizontal: 40),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text(
                    inputValue,
                    style: TextStyle(
                        fontSize: 18,
                        color: Colors.pink,
                        fontWeight: FontWeight.w600),
                  ),
                  SizedBox(
                    height: 10,
                  ),
                  TextField(
                    onChanged: (value) {
                      setState(() {
                        inputValue = value;
                      });
                    },
                    style: TextStyle(color: Colors.pink),
                    cursorColor: Colors.pink,
                    decoration: InputDecoration(
                        filled: true,
                        fillColor: Colors.pink.withOpacity(.08),
                        prefixIcon: Icon(
                          Icons.email,
                          color: Colors.pink,
                        ),
                        suffixIcon: Icon(
                          Icons.visibility,
                          color: Colors.pink,
                        ),
                        labelText: 'Enter your email',
                        labelStyle:
                            TextStyle(color: Colors.pink.withOpacity(.8)),
                        enabledBorder: OutlineInputBorder(
                            borderSide: BorderSide(color: Colors.pink),
                            borderRadius: BorderRadius.circular(30).copyWith(
                                bottomRight: Radius.circular(0),
                                topLeft: Radius.circular(0))),
                        focusedBorder: OutlineInputBorder(
                            borderSide: BorderSide(color: Colors.pink),
                            borderRadius: BorderRadius.circular(30).copyWith(
                                bottomRight: Radius.circular(0),
                                topLeft: Radius.circular(0)))),
                  )
                ],
              ))),
    ));
  }
}

Conclusion

In conclusion, you have learned how to implement Flutter textfield onChanged in Flutter app. I would love to receive your valuable feedback and also I would love to see you at my other articles on amazing Flutter widgets, beautiful Flutter templates, and amazing Flutter animations. That’s it for this article. Thanks for reading.

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