expo-camera 出现错误，TypeError: undefined is not an object (evaluating '_expoCamera.CameraType.back')

Question

我想要有关 expo-camera 中的测试代码的帮助，我正在使用 expo go，一旦运行代码，它就会出现以下错误： TypeError: undefined is not an object (evaluating '_expoCamera.CameraType.back' ），这里是expo-camera的文档：https://docs.expo.dev/versions/latest/sdk/camera/，我目前正在使用expocamera 12.3.0并使用navigation.navigate导航到这个标签谢谢！这是我直接从网站复制的代码

import { Camera, CameraType } from 'expo-camera';
import { useState } from 'react';
import { Button, StyleSheet, Text, TouchableOpacity, View } from 'react-native';

export default function App() {
  const [type, setType] = useState(CameraType.back);
  const [permission, requestPermission] = Camera.useCameraPermissions();

  if (!permission) {
    // Camera permissions are still loading
    return <View />;
  }

  if (!permission.granted) {
    // Camera permissions are not granted yet
    return (
      <View style={styles.container}>
        <Text style={{ textAlign: 'center' }}>
          We need your permission to show the camera
        </Text>
        <Button onPress={requestPermission} title="grant permission" />
      </View>
    );
  }


  function toggleCameraType() {
    setType((current) => (
      current === CameraType.back ? CameraType.front : CameraType.back
    ));
  }

  return (
    <View style={styles.container}>
      <Camera style={styles.camera} type={type}>
        <View style={styles.buttonContainer}>
          <TouchableOpacity
            style={styles.button}
            onPress={toggleCameraType}>
            <Text style={styles.text}>Flip Camera</Text>
          </TouchableOpacity>
        </View>
      </Camera>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
  },
  camera: {
    flex: 1,
  },
  buttonContainer: {
    flex: 1,
    flexDirection: 'row',
    backgroundColor: 'transparent',
    margin: 64,
  },
  button: {
    flex: 1,
    alignSelf: 'flex-end',
    alignItems: 'center',
  },
  text: {
    fontSize: 24,
    fontWeight: 'bold',
    color: 'white',
  },
});

Answer 1

更新：修复了，只需将CameraType.back更改为Camera.Constants.Type.back，解决了

Answer 2

我使用以下依赖项面临同样的问题：

    "expo": "~51.0.26",
    "expo-camera": "^15.0.14",

<Camera style={styles.camera} ref={cameraRef} type={Camera.Constant.Type.back}>

使用上面的方法返回错误：

Cannot read property 'Type' of undefined

。

尝试过：

• 重新安装软件包。
• 使用世博相机/旧版

有什么建议吗？谢谢！

代码

import { CameraView, Camera, useCameraPermissions } from 'expo-camera';

...

                {showCamera ? (
                    <View style={styles.cameraContainer}>
                        <Camera style={styles.camera} ref={cameraRef} type={Camera.Constant.Type.back}>
                            <View style={styles.cameraButtonContainer}>
                                <TouchableOpacity style={styles.cameraButton} onPress={takePicture}>
                                    <Text style={styles.buttonText}>Capture</Text>
                                </TouchableOpacity>
                                <TouchableOpacity style={styles.cameraButton} onPress={() => setShowCamera(false)}>
                                    <Text style={styles.buttonText}>Cancel</Text>
                                </TouchableOpacity>
                            </View>
                        </Camera>
                    </View>