Flutter TextField onChanged

In flutter, controllers are a means to give control to the parent widget over its child state . The main selling point of controllers is that they remove the need of a GlobalKey to access the widget State. This, in turn, makes it harder to do anti-pattern stuff and increase performances.

onChanged. Called when the user initiates a change to the TextField’s value: when they have inserted or deleted text . This callback doesn’t run when the TextField’s text is changed programmatically, via the TextField’s controller.

TextField. TextField is the most commonly used text input widget. By default, a TextField is decorated with an underline. You can add a label, icon, inline hint text, and error text by supplying an InputDecoration as the decoration property of the TextField .

Editable Text in Flutter.