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flutter - How to use TextField

Flutter TextField
The TextField class represents a material design text field. The TextField widget lets the user enter text, either with a hardware keyboard or with an onscreen keyboard.

The TextField calls the onChanged callback whenever the user changes the text in the field. The flutter developers can control the text that is displayed in the TextField using the controller.

The controller allows developers to set an initial value. The controller can also control the selection and composing region and observe changes to the text, selection, and composing region.

The flutter developers can use TextField decoration property to control the decoration, for example by adding a label or an icon.

The flutter developers can read the value from a TextField widget to use the onSubmitted callback. The onSubmitted callback is applied to TextField's current value when the user finishes editing.

The flutter app developers can always read the current string from TextField's TextEditingController using TextEditingController.text.

The TextField class has many useful properties such as autocorrect, autofocus, clipBehavior, controller, cursorColor, decoration, enabled, enableSuggestions, expands, keyboardAppearance, keyboardType, maxLength, maxLines, minLines, onChanged, onEditingComplete, onSubmitted, onTap, onTapOutside, readOnly, scrollController, selectionControls, selectionEnabled, showCursor, style, textAlign, textCapitalization, and textDirection.

The TextField class also has several useful methods for example createElement(), createState(), debugDescribeChildren(), toString(), toStringDeep(), and toStringShallow().

In this flutter example code, we put a Text widget, a TextField widget, and an ElevatedButton widget. TextField allows the user to write text and the ElevatedButton widget’s press event displays the inputted text on the Text widget.
main.dart

import 'package:flutter/material.dart';

void main() => runApp(const FlutterExample());

class FlutterExample extends StatelessWidget {
  const FlutterExample({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Example',
        theme: ThemeData(primarySwatch: Colors.teal),
        home: const StateExample());
  }
}

class StateExample extends StatefulWidget {
  const StateExample({Key? key}) : super(key: key);

  @override
  _StateExampleState createState() => _StateExampleState();
}

class _StateExampleState extends State<StateExample> {
  String inputtedText  = "Input your name.";
  final textEditingController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFFFEFEFA),
      appBar: AppBar(
        title: const Text("Flutter - TextField Example"),
      ),
      body: bodyContent(),
    );
  }

  bodyContent() {
    return Center(
        child: SizedBox(
            width: 250,
            child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: [
                  Text(
                    inputtedText,
                    style: const TextStyle(
                        fontWeight: FontWeight.bold,
                        color: Color(0xFF2243B6),
                        fontSize: 21
                    ),
                  ),
                  const SizedBox(height: 10),
                  TextField(
                    controller: textEditingController,
                  ),
                  const SizedBox(height: 10),
                  ElevatedButton(
                      onPressed: () {
                        setState(() {
                          inputtedText = textEditingController.text;
                        });
                      },
                      child: const Text("Show Inputted Name"),
                      style: ElevatedButton.styleFrom(
                        padding: const EdgeInsets.all(20),
                      )
                  )
                ]
            )
        )
    );
  }
}
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