我正在开发一个自定义相机，但在尝试使用Camera 2 api拍摄图像时，我正在获取黑色图像。我使用下面的代码进行捕获
CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
String cameraId = "";
if (cameraFront) {
cameraId = "" + findFrontFacingCamera();
} else {
cameraId = "" + findBackFacingCamera();
}
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
// CameraCharacteristics characteristics = manager.getCameraCharacteristics(mCameraDevice.getId());
Size[] jpegSizes = null;
if (characteristics != null) {
jpegSizes =
characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(
ImageFormat.JPEG);
}
int width = 720;
int height = 640;
if (jpegSizes != null && 0 < jpegSizes.length) {
width = jpegSizes[0].getWidth();
height = jpegSizes[0].getHeight();
}
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size largest =
Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)), new CompareSizesByArea());
ImageReader reader =
ImageReader.newInstance(largest.getWidth(), largest.getHeight(), ImageFormat.JPEG, /* maxImages */1);
// ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);
List<Surface> outputSurfaces = new ArrayList<Surface>(2);
outputSurfaces.add(reader.getSurface());
outputSurfaces.add(new Surface(mTextureView.getSurfaceTexture()));
final CaptureRequest.Builder captureBuilder =
mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
captureBuilder.addTarget(reader.getSurface());
captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
captureBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
// Orientation
int rotation = getWindowManager().getDefaultDisplay().getRotation();
if (cameraFront) {
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation) + 180);
} else {
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
}
final File file = getOutputMediaFile();
ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener()
{
@Override
public void onImageAvailable(ImageReader reader)
{
Image image = null;
try {
image = reader.acquireLatestImage();
// ByteBuffer buffer = image.getPlanes()[0].getBuffer();
// final byte[] bytes = new byte[buffer.capacity()];
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
final byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes);
save(bytes);
buffer.clear();
runOnUiThread(new Runnable()
{
@Override
public void run()
{
mThumbnail.setVisibility(View.VISIBLE);
filePathLabel.setVisibility(View.VISIBLE);
filePathValue.setText(file.getAbsolutePath());
Bitmap bmp =
UtilityMethods.getScaledBitmap(CameraImageTestActivityLoliipop.this, bytes);
mThumbnail.setImageBitmap(bmp);
}
});
} catch (FileNotFoundException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
} catch (IOException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
} finally {
if (image != null) {
image.close();
}
}
}
private void save(byte[] bytes) throws IOException
{
OutputStream output = null;
try {
output = new FileOutputStream(file);
output.write(bytes);
} finally {
if (null != output) {
output.close();
}
}
}
};
HandlerThread thread = new HandlerThread("CameraPicture");
thread.start();
final Handler backgroudHandler = new Handler(thread.getLooper());
reader.setOnImageAvailableListener(readerListener, backgroudHandler);
final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback()
{
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
TotalCaptureResult result)
{
super.onCaptureCompleted(session, request, result);
startPreview();
}
};
mCameraDevice.createCaptureSession(outputSurfaces, new CameraCaptureSession.StateCallback()
{
@Override
public void onConfigured(CameraCaptureSession session)
{
try {
session.capture(captureBuilder.build(), captureListener, backgroudHandler);
} catch (CameraAccessException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session)
{
}
}, backgroudHandler);
} catch (CameraAccessException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
}
and below are the methods for camera preview
protected void startPreview（） { 试试{
if (null == mCameraDevice || !mTextureView.isAvailable() || null == mPreviewSize) {
Log.e(TAG, "startPreview fail, return");
return;
}
SurfaceTexture texture = mTextureView.getSurfaceTexture();
if (null == texture) {
Log.e(TAG, "texture is null, return");
return;
}
Log.e(TAG, "Width: " + mPreviewSize.getWidth() + " Hieght : " + mPreviewSize.getHeight());
texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
Surface surface = new Surface(texture);
try {
mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
mPreviewBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
} catch (CameraAccessException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
}
mPreviewBuilder.addTarget(surface);
mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback()
{
@Override
public void onConfigured(CameraCaptureSession session)
{
mPreviewSession = session;
updatePreview();
}
@Override
public void onConfigureFailed(CameraCaptureSession session)
{
}
}, null);
} catch (CameraAccessException e) {
AppLogger.exception(myContext, getClass().getSimpleName(), e);
// e.printStackTrace();
}
}
protected void updatePreview()
{
try {
if (null == mCameraDevice) {
Log.e(TAG, "updatePreview error, return");
}
mPreviewBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
// mPreviewBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// Flash is automatically enabled when necessary.
mPreviewBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
HandlerThread thread = new HandlerThread("CameraPreview");
thread.start();
Handler backgroundHandler = new Handler(thread.getLooper());
mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, backgroundHandler);
} catch (CameraAccessException e) {
}
它可以在所有设备上工作，但是当我在Micromax Q382设备上运行时，然后在logcat中获得以下警告的黑色图像
I / Choreographer：跳过37帧！应用程序可能在其主线程上做了太多工作。 W / ImageReader_JNI：无法获取lockedBuffer，很可能客户端尝试锁定超过maxImages缓冲区
我不知道发生了什么。请帮助我。
答案 0 :(得分：0)
您可以尝试在开始捕捉之前（以及打开相机后）设置一些延迟。类似的东西：
new Handler().postDelayed(() -> {
//takePicture();
}, 500);
如果您愿意，我已经创建了一项服务，可以大规模使用Android Camera 2 API进行照片捕捉：https://github.com/hzitoun/android-camera2-secret-picture-taker。自述文件中描述了用法。
希望有所帮助！
答案 1 :(得分：0)
您将AE模式设置为“始终闪烁”，但是您不会运行预捕获序列以允许相机设备测量该闪光灯;这在任何设备上都可能无法正常工作，在某些设备上，您最终可能会遇到一些默认曝光值（不良）。
如果要激活闪光灯，则需要先在非LEGACY设备上使用预捕获序列（发送设置为AE_PRECAPTURE_TRIGGER的单个请求，等待PRECAPTURE AE_STATE结束，然后发出捕获请求）。如果设备是LEGACY级别，那么您当前的代码应该没问题。
答案 2 :(得分：0)
您在null内向createCaptureSession传递startPreview个参数。使之前使用的backgroudHandler对该方法可见（作为参数传递或将其初始化为类变量）并在那里使用。