flutter_ali_camera/lib/camera_view.dart

import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_ali_camera/camera_export.dart';

typedef OnCameraViewCreated(CameraViewController controller);

class CameraView extends StatefulWidget {
  final OnCameraViewCreated onCameraViewCreated;
  final Rect widgetRect; // use for measure view size on iOS

  const CameraView({Key key, this.onCameraViewCreated, this.widgetRect}) : super(key: key);

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

class _CameraViewState extends State<CameraView> {
  static const String viewType = "com.i2edu.cameraLib";

  @override
  Widget build(BuildContext context) {
    return Platform.isAndroid
        ? AndroidView(
            viewType: viewType,
            creationParams: {},
            creationParamsCodec: const StandardMessageCodec(),
            onPlatformViewCreated: onPlatformViewCreated,
          )
        : UiKitView(
            viewType: viewType,
            creationParams: {
              "x": widget.widgetRect.left,
              "y": widget.widgetRect.top,
              "width": widget.widgetRect.width,
              "height": widget.widgetRect.height,
            },
            creationParamsCodec: const StandardMessageCodec(),
            onPlatformViewCreated: onPlatformViewCreated,
          );
  }

  void onPlatformViewCreated(int viewId) {
    final CameraViewController controller = CameraViewController(id: viewId);
    if (widget.onCameraViewCreated != null) {
      widget.onCameraViewCreated(controller);
    }
  }
}