[Fix] Error: The Method 'FlatButton' Isn't Defined For The Type 'CartScreen' 2023

The Error “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.”, is an error that is seen when you are working on flutter and are trying to use the FlatButton graphic in flutter after recently upgrading to version 3.3.0.

Given below is the snippet of the error you might get:

error: The method 'FlatButton' isn't defined for the type 'CartScreen'.

The error, “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.” is seen because the recent Flutter version 3.3.0 gotten rid of deprecated RaisedButton. The documentation for the above changes in the recent version flutter that is version 3.3.0 can be found here.

As per Flutter 3.3.0 Version: Remove deprecated FlatButton by @Piinks in https://github.com/flutter/flutter/pull/98545

To fix the error, “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.”, change the Flatbutton widget to the TextButton into your code as Flatbutton widget is replaced with the TextButton in the latest flutter 3.3.0 version and error would be fixed.

Steps to fix the error “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.” is mentioned below:

First, you will have to use the code in the recent version of flutter to know how to get the old look of the flatbutton.

The Flatbutton widget is replaced with the TextButton in the latest version of flutter.

You can check the recent button changes in the image shown below:

*Error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’*

You can have the same visual look by using the code mentioned below:

// Use the following information to migrate your buttons to the new API.


final ButtonStyle flatButtonStyle = TextButton.styleFrom(
  primary: Colors.black87,
  minimumSize: Size(88, 36),
  padding: EdgeInsets.symmetric(horizontal: 16.0),
  shape: const RoundedRectangleBorder(
    borderRadius: BorderRadius.all(Radius.circular(2.0)),
  ),
);

TextButton(
  style: flatButtonStyle,
  onPressed: () { },
  child: Text('Looks like a FlatButton'),
)

Information for restoring the original button graphics is available in the link mentioned below.

*Flutter 3.3.0 version: Restoring the original button visuals*

This should help you fix the error, “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.”.

Conclusion

To fix the error, “error: The method ‘FlatButton’ isn’t defined for the type ‘CartScreen’.”, you will have to check the recent changes in the recent version of the version 3.3.0.

The verison 3.3.0 of flutter, the recent version gotten rid of deprecated RaisedButton.

The documentation for the above changes in the recent version flutter that is version 3.3.0 can be found here