我无法弄清楚如何使用react-native-camera捕获方法获取捕获图像的元数据。
我假设它是这样的：
this.camera.capture({metadata: true})
.then((data) => console.log(data))
.catch(error => alert("error: " + error));
但它只返回路径，所以：
this.camera.capture({metadata: 'location'})
.then((data) => console.log(data))
.catch(error => alert("error: " + error));
我不清楚文档元数据的使用情况。 传递元数据参数的正确方法是什么？ 有没有人让这个工作？
答案 0 :(得分：2)
这可能是在黑暗中拍摄的，但如果您阅读了README.md https://github.com/lwansbrough/react-native-camera的第一段，它会说：
这些文档适用于正在进行的工作v1发布。如果你想使用最新的和最好的，并且可以处理明显的不稳定性，你可以使用npm install --save lwansbrough / react-native-camera安装。
该库的NPM版本为0.3.8：https://www.npmjs.com/package/react-native-camera。
修改：
所以我去0.3.8安装库并进入node_modules查看Java代码（假设你在Android手机上测试它）并搜索本机{{1函数和那里没有任何处理capture选项的东西，这很难过。尝试搜索metadata，但您找不到任何内容：
metadata但是，我查看了iOS端，看到他们确实处理了那里的@ReactMethod
public void capture(final ReadableMap options, final Promise promise) {
int orientation = options.hasKey("orientation") ? options.getInt("orientation") : RCTCamera.getInstance().getOrientation();
if (orientation == RCT_CAMERA_ORIENTATION_AUTO) {
_sensorOrientationChecker.onResume();
_sensorOrientationChecker.registerOrientationListener(new RCTSensorOrientationListener() {
@Override
public void orientationEvent() {
int deviceOrientation = _sensorOrientationChecker.getOrientation();
_sensorOrientationChecker.unregisterOrientationListener();
_sensorOrientationChecker.onPause();
captureWithOrientation(options, promise, deviceOrientation);
}
});
} else {
captureWithOrientation(options, promise, orientation);
}
}
private void captureWithOrientation(final ReadableMap options, final Promise promise, int deviceOrientation) {
Camera camera = RCTCamera.getInstance().acquireCameraInstance(options.getInt("type"));
if (null == camera) {
promise.reject("No camera found.");
return;
}
if (options.getInt("mode") == RCT_CAMERA_CAPTURE_MODE_VIDEO) {
record(options, promise);
return;
}
RCTCamera.getInstance().setCaptureQuality(options.getInt("type"), options.getString("quality"));
if (options.hasKey("playSoundOnCapture") && options.getBoolean("playSoundOnCapture")) {
MediaActionSound sound = new MediaActionSound();
sound.play(MediaActionSound.SHUTTER_CLICK);
}
if (options.hasKey("quality")) {
RCTCamera.getInstance().setCaptureQuality(options.getInt("type"), options.getString("quality"));
}
final Boolean shouldMirror = options.hasKey("mirrorImage") && options.getBoolean("mirrorImage");
RCTCamera.getInstance().adjustCameraRotationToDeviceOrientation(options.getInt("type"), deviceOrientation);
camera.takePicture(null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
if (shouldMirror) {
data = mirrorImage(data);
if (data == null) {
promise.reject("Error mirroring image");
}
}
camera.stopPreview();
camera.startPreview();
WritableMap response = new WritableNativeMap();
switch (options.getInt("target")) {
case RCT_CAMERA_CAPTURE_TARGET_MEMORY:
String encoded = Base64.encodeToString(data, Base64.DEFAULT);
response.putString("data", encoded);
promise.resolve(response);
break;
case RCT_CAMERA_CAPTURE_TARGET_CAMERA_ROLL: {
File cameraRollFile = getOutputCameraRollFile(MEDIA_TYPE_IMAGE);
if (cameraRollFile == null) {
promise.reject("Error creating media file.");
return;
}
Throwable error = writeDataToFile(data, cameraRollFile);
if (error != null) {
promise.reject(error);
return;
}
addToMediaStore(cameraRollFile.getAbsolutePath());
response.putString("path", Uri.fromFile(cameraRollFile).toString());
promise.resolve(response);
break;
}
case RCT_CAMERA_CAPTURE_TARGET_DISK: {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null) {
promise.reject("Error creating media file.");
return;
}
Throwable error = writeDataToFile(data, pictureFile);
if (error != null) {
promise.reject(error);
return;
}
addToMediaStore(pictureFile.getAbsolutePath());
response.putString("path", Uri.fromFile(pictureFile).toString());
promise.resolve(response);
break;
}
case RCT_CAMERA_CAPTURE_TARGET_TEMP: {
File tempFile = getTempMediaFile(MEDIA_TYPE_IMAGE);
if (tempFile == null) {
promise.reject("Error creating media file.");
return;
}
Throwable error = writeDataToFile(data, tempFile);
if (error != null) {
promise.reject(error);
}
response.putString("path", Uri.fromFile(tempFile).toString());
promise.resolve(response);
break;
}
}
}
});
}
对象。
修改：
此外，metadata分支仍然无法处理master选项。见here。您似乎必须指定一个特定的metadata，并且根据具体情况，它会返回一个特定的数据类型，但遗憾的是没有任何与位置相关的内容。