我试图给一个白色的圆形边框的TouchableOpacity，但白色转换成灰色的黑色背景，谁能告诉我如何解决这个问题，使其白色？TouchableOpacity是一个圆形。我使用的TouchableOpacity由react-native和相机，我使用expo-camera，因为我使用react native expo
我的代码：

export default function CameraUncle({ navigation }) {
  const [hasPermission, setHasPermission] = useState(null);
  const cameraRef = useRef(null);
  const [faceData, setFaceData] = useState([]);

  useEffect(() => {
    (async () => {
      const { status } = await Camera.requestCameraPermissionsAsync();
      setHasPermission(status === 'granted');
    })();
  }, []);

  if (hasPermission === null) {
    return <View />;
  }

  if (hasPermission === false) {
    return <Text>No access to camera</Text>;
  }

  const handleTakePicture = async () => {
    if (faceData.length === 0) {
      alert('No Face')
    }
    else if
      (cameraRef.current) {
      const photo = await cameraRef.current.takePictureAsync();
      console.log(photo.uri)
      if (!photo.cancelled) {
        navigation.navigate('addpost', { postImage: photo.uri });
      }
    }
  }

  const handleFacesDetected = ({ faces }) => {
    setFaceData(faces);
  }

  return (
    <View style={{ flex: 1, backgroundColor: 'black' }}>
      <Camera
        onFacesDetected={handleFacesDetected}
        faceDetectorSettings={{
          mode: FaceDetector.FaceDetectorMode.fast,
          detectLandmarks: FaceDetector.FaceDetectorLandmarks.none,
          runClassifications: FaceDetector.FaceDetectorClassifications.none,
          minDetectionInterval: 100,
          tracking: true,
        }}
        style={{
          borderTopLeftRadius: 30,
          borderTopRightRadius: 30,
          borderBottomLeftRadius: 30,
          borderBottomRightRadius: 30,
          overflow: 'hidden',
          width: '130%',
          aspectRatio: 1,
        }}
        type={Camera.Constants.Type.front}
        ref={cameraRef}
      >

        <View style={{ flex: 1, backgroundColor: 'transparent', flexDirection: 'row' }}>

        </View>
      </Camera>
      <View style={{
        alignSelf: 'center',
        alignItems: 'center',
        width: 90,
        height: 90,
        borderRadius: 500,
        marginTop: '30%',
        marginLeft: '5%',
        borderColor: 'white',
        borderWidth: 4
      }}>
        <TouchableOpacity
          onPress={handleTakePicture}
        >
          <View style={{ opacity: 0.5 }} />
        </TouchableOpacity>
      </View>

    </View >
  );
}