플러터 - 콜백 함수 연습 예제

코드 1

 

---

import 'package:flutter/material.dart';
 
main() {
  runApp(
    MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
        body: Body(),
      ),
    ),
  );
}
 
class Body extends StatelessWidget {
  const Body({super.key});
 
  @override
  Widget build(BuildContext context) {
    return TestWidget();
  }
}
 
class TestWidget extends StatefulWidget {
  const TestWidget({super.key});
 
  @override
  State<TestWidget> createState() => _TestWidgetState();
}
 
class _TestWidgetState extends State<TestWidget> {
  int value = 0;
 
  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Text(
          'Count: $value',
          style: const TextStyle(fontSize: 30),
        ),
        TestButton(addCounter),
      ],
    );
  }
 
  void addCounter(int addValue) {
    setState(() => value = addValue + value);
  }
}
 
class TestButton extends StatelessWidget {
  const TestButton(this.callback, {super.key});
 
  final Function(int) callback;
 
  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.symmetric(vertical: 8),
      width: double.infinity,
      child: InkWell(
        onTap: () => callback.call(1),
        onDoubleTap: () => callback.call(5),
        onLongPress: () => callback.call(10),
        child: Center(
          child: Container(
            padding: const EdgeInsets.symmetric(vertical: 4, horizontal: 8),
            decoration: BoxDecoration(border: Border.all()),
            child: const Text(
              'Up Counter',
              style: TextStyle(fontSize: 24),
            ),
          ),
        ),
      ),
    );
  }
}