douyin_demo/lib/providers/CameraProvider.dart

import 'dart:io';

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

import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'package:uuid/uuid.dart';

class CameraProvider with ChangeNotifier {
  CameraController cameraController;
  List<CameraDescription> cameras;
  int curCamera = 0;
  String appFolder = "";
  String fileName;

  CameraProvider() {
    getCameras();
  }

  changeFileName(){
    String id=Uuid().v4().toString();
    fileName=p.join(appFolder,'$id.png');
    notifyListeners();
  }

  getCameras() async {
    Directory appDocDir = await getApplicationDocumentsDirectory();
    if(!Directory(appDocDir.path).existsSync()){
      appDocDir.createSync();
    }
    appFolder = appDocDir.path;
    cameras = await availableCameras();
    cameraController =
        CameraController(cameras[curCamera], ResolutionPreset.max);
    cameraController.initialize().then((_) {
      notifyListeners();
    });
  }

  changeCamera() {
    if (curCamera == 0) {
      curCamera = 1;
    } else {
      curCamera = 0;
    }
    cameraController =
        CameraController(cameras[curCamera], ResolutionPreset.max);
    cameraController.initialize().then((_) {
      notifyListeners();
    });
  }
}