[Flutter/Project](Instagram Clone) SliverToBoxAdapter(), GridView.count

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소스코드

// profile_body.dart

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:flutter_project_IJ/constants/common_size.dart';
import 'package:flutter_project_IJ/constants/screen_size.dart';

// 가독성을 위해서 사용.
enum SelectedTab { left, right }

class ProfileBody extends StatefulWidget {
  @override
  _ProfileBodyState createState() => _ProfileBodyState();
}

class _ProfileBodyState extends State<ProfileBody> {
  // bool selectedLeft = true;
  SelectedTab _selectedTab = SelectedTab.left;

  @override
  Widget build(BuildContext context) {
    return Expanded(
      // CustomScrollView()가 빈공간을 차지하도록 해야 표시됨.
      child: CustomScrollView(
        // CustomScrollView() 스크롤 가능한 뷰들을 섞어서 사용할 때.
        slivers: <Widget>[
          SliverList(
            delegate: SliverChildListDelegate([
              _username(),
              _userBio(),
              _editProfileBtn(),
              _tabButtons(),
              _selectedIndicator(),
            ]),
          ),
          SliverToBoxAdapter(
            // SliverToBoxAdapter() 일반적인 뷰를 Sliver 뷰로 변환.
            child: GridView.count(
              crossAxisCount: 3,
              physics:
                  NeverScrollableScrollPhysics() /* GridView의 스크롤을 사용하지 않음 */,
              shrinkWrap: true /* 데이터의 양 만큼만 공간을 차지하게함 */,
              childAspectRatio: 1 /* 이미지 비율 */,
              children: List.generate(
                // List.generate() 리스트 생성
                30,
                (index) => CachedNetworkImage(
                  fit: BoxFit.cover,
                  imageUrl: "https://picsum.photos/id/$index/100/100",
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _selectedIndicator() {
    return AnimatedContainer(
      duration: Duration(milliseconds: 300),
      alignment: _selectedTab == SelectedTab.left
          ? Alignment.centerLeft
          : Alignment.centerRight,
      curve: Curves.fastOutSlowIn,
      child: Container(
        height: 3,
        width: size.width / 2,
        color: Colors.black87,
      ),
    );
  }

  Row _tabButtons() {
    return Row(
      children: [
        Expanded(
          child: IconButton(
            color: _selectedTab == SelectedTab.left
                ? Colors.black
                : Colors.black38,
            icon: ImageIcon(AssetImage('assets/images/grid.png')),
            onPressed: () {
              setState(() {
                // StatefulWidget의 상태변화 적용.
                _selectedTab = SelectedTab.left;
              });
            },
          ),
        ),
        Expanded(
          child: IconButton(
            color: _selectedTab == SelectedTab.left
                ? Colors.black38
                : Colors.black,
            icon: ImageIcon(AssetImage('assets/images/saved.png')),
            onPressed: () {
              setState(() {
                // StatefulWidget의 상태변화 적용.
                _selectedTab = SelectedTab.right;
              });
            },
          ),
        ),
      ],
    );
  }

  Widget _editProfileBtn() {
    return Padding(
      padding: const EdgeInsets.symmetric(
        horizontal: common_gap,
        vertical: common_xxs_gap,
      ),
      child: SizedBox(
        height: 24,
        child: OutlineButton(
          onPressed: () {},
          borderSide: BorderSide(color: Colors.black45),
          shape: RoundedRectangleBorder(
            // RoundedRectangleBorder() 둥근 모서리 직사각형.
            borderRadius: BorderRadius.circular(6),
          ),
          child: Text(
            'Edit Profile',
            style: TextStyle(fontWeight: FontWeight.bold),
          ),
        ),
      ),
    );
  }

  Widget _username() {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: common_gap),
      child: Text(
        'username',
        style: TextStyle(fontWeight: FontWeight.bold),
      ),
    );
  }

  Widget _userBio() {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: common_gap),
      child: Text(
        'username',
        style: TextStyle(fontWeight: FontWeight.w400),
      ),
    );
  }
}