[Flutter] 6. Constraints

• Container
• min : 0
• max : double.infinity
• 크기를 주지 않고, 자식이 있으면 (자식 크기만큼 줄어듬)

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Constraints Example')),
        body: Center(
          child: Container(
            color: Colors.blue,
            constraints: BoxConstraints(
              // 1. 부모는 자식에게 제약조건을 전파
              minWidth: 0,
              minHeight: 0,
              maxWidth: double.infinity,
              maxHeight: double.infinity,
            ),
            child: Container(
              color: Colors.red,
              // 2. 자식은 부모의 제약조건 내에서만 동작
              // 3. 자식은 크기가 없으면 Max 값을 따름
              child: Center(child: Text('Child')),
            ),
          ),
        ),
      ),
    );
  }
}

예제

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Constraints Example')),
        body: ListView(
          children: [
            AspectRatio(
              aspectRatio: 1 / 1,
              child: Image.asset("test.png", fit: BoxFit.cover),
            ),
          ],
        ),
      ),
    );
  }
}