所以，事情是这样的。我试图在自动对焦锁定后立即从相机预览中获取照片。我现在能够做到这一点并且效果很好。现在，在捕获图片时，它会暂时阻止预览。我想在不妨碍预览的情况下完成整个捕获过程。有办法解决吗？
这是我当前的代码，它是基于 Google 示例相机 2 代码构建的。
boolean areWeFocused = false;
int counter =0;
/**
* A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture.
*/
private CameraCaptureSession.CaptureCallback mCaptureCallback
= new CameraCaptureSession.CaptureCallback() {
private void process(CaptureResult result) {
Integer afState = result.get(CaptureResult.CONTROL_AF_STATE);
switch (mState) {
case STATE_PREVIEW: {
// We have nothing to do when the camera preview is working normally.
if (CaptureResult.CONTROL_AF_TRIGGER_START == afState) {
if (areWeFocused) {
//Run specific task here
counter++;
takePicture();
Log.d("FocussedState","I am focussed now");
}
}
if (CaptureResult.CONTROL_AF_STATE_PASSIVE_FOCUSED == afState) {
areWeFocused = true;
} else {
areWeFocused = false;
Log.d("FocussedState","I am not focussed now");
}
break;
}
}
private void takePicture() {
lockFocus();
}
/**
* Lock the focus as the first step for a still image capture.
*/
private void lockFocus() {
try {
// This is how to tell the camera to lock focus.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
CameraMetadata.CONTROL_AF_TRIGGER_START);
// Tell #mCaptureCallback to wait for the lock.
mState = STATE_WAITING_LOCK;
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void captureStillPicture() {
try {
final Activity activity = getActivity();
if (null == activity || null == mCameraDevice) {
return;
}
// This is the CaptureRequest.Builder that we use to take a picture.
final CaptureRequest.Builder captureBuilder =
mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(mImageReader.getSurface());
// Use the same AE and AF modes as the preview.
captureBuilder.set(CaptureRequest.CONTROL_AF_MODE,
CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// setAutoFlash(captureBuilder);
// Orientation
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getOrientation(rotation));
CameraCaptureSession.CaptureCallback CaptureCallback
= new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request,
@NonNull TotalCaptureResult result) {
showToast("Saved: " + mFile);
Log.d(TAG, mFile.toString());
unlockFocus();
}
};
mCaptureSession.stopRepeating();
mCaptureSession.abortCaptures();
mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private ImageReader mImageReader;
/**
* This is the output file for our picture.
*/
private File mFile;
/**
* This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a
* still image is ready to be saved.
*/
private final ImageReader.OnImageAvailableListener mOnImageAvailableListener
= new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
mBackgroundHandler.post(new ImageSaver(reader.acquireNextImage(), mFile));
}
};
private static class ImageSaver implements Runnable {
/**
* The JPEG image
*/
private final Image mImage;
/**
* The file we save the image into.
*/
private final File mFile;
ImageSaver(Image image, File file) {
mImage = image;
mFile = file;
}
@Override
public void run() {
ByteBuffer buffer = mImage.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes);
FileOutputStream output = null;
try {
output = new FileOutputStream(mFile);
output.write(bytes);
} catch (IOException e) {
e.printStackTrace();
} finally {
mImage.close();
if (null != output) {
try {
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
/**
* Compares two {@code Size}s based on their areas.
*/
static class CompareSizesByArea implements Comparator<Size> {
@Override
public int compare(Size lhs, Size rhs) {
// We cast here to ensure the multiplications won't overflow
return Long.signum((long) lhs.getWidth() * lhs.getHeight() -
(long) rhs.getWidth() * rhs.getHeight());
}
}
最佳答案
尝试删除 captureStillPicture 末尾的“mCaptureSession.stopRepeating()”和“abortCaptures”。
这些会阻止预览运行，直到重新启动为止，并且中止可能会导致输出出现故障。不过，它可以稍微加快捕捉时间，这可能就是它在那里的原因。
关于java - 在不阻塞预览camera2 api的情况下从后台相机预览中捕获图片的可能方法？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48189281/