[Flutter/Project](Instagram Clone) unique post key 생성

postKey 생성 확인

---

repo/helper/generate_post_key.dart

screens/share_post_screen.dart

widgets/take_photo.dart

widgets/my_gallery.dart

---

소스코드 및 pubspec.yaml

// repo/helper/generate_post_key.dart

import 'package:flutter_project_IJ/models/firestore/user_model.dart';

// 시간_유저키로 파일명 생성.
String getNewPostKey(UserModel userModel) =>
    "${DateTime.now().millisecondsSinceEpoch}_${userModel.userKey}";
// millisecondsSinceEpoch -> UTC의 시간을 밀리초로 가져옴

// screens/share_post_screen.dart

import 'dart:io';
import 'package:flutter/material.dart';

class SharePostScreen extends StatelessWidget {
  final File imageFile;
  final String postKey;

  const SharePostScreen(this.imageFile, {Key key, @required this.postKey})
      : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Image.file(imageFile);
  }
}

// widgets/my_gallery.dart

import 'dart:io';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:flutter_project_IJ/models/gallery_state.dart';
import 'package:flutter_project_IJ/models/user_model_state.dart';
import 'package:flutter_project_IJ/repo/helper/generate_post_key.dart';
import 'package:flutter_project_IJ/screens/share_post_screen.dart';
import 'package:local_image_provider/device_image.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:provider/provider.dart';

class MyGallery extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<GalleryState>(
      builder: (BuildContext context, GalleryState galleryState, Widget child) {
        return GridView.count(
          crossAxisCount: 3,
          children: getImages(context, galleryState),
        );
      },
    );
  }

  List<Widget> getImages(BuildContext context, GalleryState galleryState) {
    return galleryState.images
        .map((localImage) => InkWell(
              onTap: () async {
                // 로컬 이미지를 File 형식으로 바로 변경할 수 없기에
                // 로컬 이미지를 byte 이미지로 변경해야함.
                Uint8List bytes = await localImage.getScaledImageBytes(
                    galleryState.localImageProvider, 0.5);

                final String postKey = getNewPostKey(
                    Provider.of<UserModelState>(context, listen: false).userModel);
                try {
                  // 이미지 저장 경로 및 파일이름
                  final path = join(
                      (await getTemporaryDirectory()).path, '$postKey.png');
                  // .. -> File 생성 후 writeAsBytesSync(bytes) 실행.
                  // File을 bytes 목록으로 작성 후 imageFile 변수에 저장.
                  File imageFile = File(path)..writeAsBytesSync(bytes);
                  // 사진 선택시 미리보기 화면으로 넘어감.
                  // byte로 변환된 imageFile을 SharePostScreen 클래스로 넘김.
                  Navigator.push(
                      context,
                      MaterialPageRoute(
                          builder: (_) => SharePostScreen(
                                imageFile,
                                postKey: postKey,
                              )));
                } catch (e) {}
              },
              child: Image(
                // 이미지 1대1 사이즈 맞춤.
                fit: BoxFit.cover,
                // 갤러리 이미지 표시.
                // 원본의 10% 사이즈로 표시(메모리 부족).
                image: DeviceImage(localImage, scale: 0.1),
              ),
            ))
        .toList();
  }
}

// widgets/take_photo.dart

import 'dart:io';

import 'package:camera/camera.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_project_IJ/constants/screen_size.dart';
import 'package:flutter_project_IJ/models/camera_state.dart';
import 'package:flutter_project_IJ/models/user_model_state.dart';
import 'package:flutter_project_IJ/repo/helper/generate_post_key.dart';
import 'package:flutter_project_IJ/screens/share_post_screen.dart';
import 'package:flutter_project_IJ/widgets/my_progress_indicator.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:provider/provider.dart';

class TakePhoto extends StatefulWidget {
  const TakePhoto({
    Key key,
  }) : super(key: key);

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

class _TakePhotoState extends State<TakePhoto> {
  Widget _progress = MyProgressIndicator();

  @override
  Widget build(BuildContext context) {
    return Consumer(
      builder: (BuildContext context, CameraState cameraState, Widget child) {
        return Column(
          children: [
            Container(
              color: Colors.black,
              height: size.width,
              width: size.width,
              child: (cameraState.isReadyToTakePhoto)
                  ? _getPreview(cameraState)
                  : _progress,
            ),
            Expanded(
              child: OutlineButton(
                onPressed: () {
                  // 카메라 준비 확인.
                  if (cameraState.isReadyToTakePhoto) {
                    _attemptTakePhoto(cameraState, context);
                  }
                },
                shape: CircleBorder(),
                borderSide: BorderSide(
                  color: Colors.black12,
                  width: 20,
                ),
              ),
            )
          ],
        );
      },
    );
  }

  Widget _getPreview(CameraState cameraState) {
    return ClipRect(
      // OverflowBox로 넘어간 부분을 제거.
      child: OverflowBox(
        alignment: Alignment.center,
        child: FittedBox(
          // 가로사이즈에 맞춤.
          fit: BoxFit.fitWidth,
          child: Container(
            width: size.width,
            height: size.width / cameraState.controller.value.aspectRatio,
            child: CameraPreview(cameraState.controller),
          ),
        ),
      ),
    );
  }

  void _attemptTakePhoto(CameraState cameraState, BuildContext context) async {
    final String postKey = getNewPostKey(
        Provider.of<UserModelState>(context, listen: false).userModel);
    try {
      // 이미지 저장 경로 및 파일이름
      final path = join((await getTemporaryDirectory()).path, '$postKey.png');
      // 사진 촬영
      await cameraState.controller.takePicture(path);

      File imageFile = File(path);
      // 사진 촬영 후 미리보기 화면으로 넘어감.
      Navigator.push(
          context,
          MaterialPageRoute(
              builder: (_) => SharePostScreen(
                    imageFile,
                    postKey: postKey,
                  )));
    } catch (e) {}
  }
}