问题
I want to use Camera2 API to get a single frame from the camera and display it with ImageView. I found some close questions such as
https://stackoverflow.com/questions/25462277/camera-preview-image-data-processing-with-android-l-and-camera2-api
And also I've looked at Camera2Basic example but it was too complex and not exactly what I needed.
I wrote the code, that is based on some examples I saw on the web, that should do it but it doesn't work and I can't figure out why.
The app doesn't crash but simply doesn't display any content on the ImageView. I used Log messages in any function call in order to try and keep the logcat clear.
Also, the app is logcat says that "the application may be doing too much work on the background.." I don't see how is it possible because I made a single captureRequest and not a repeatingCaptureRequest.
Here's the code and the logcat: Code:
public class CameraImageReaderActivity extends AppCompatActivity {
private final static String TAG = "CAMERA_IMAGE_READY: ";
private ImageReader imageReader;
private String cameraId;
private CameraDevice camera;
private HandlerThread handlerThread;
private Handler handler;
private Surface imageReaderSurface;
private ImageView imageView;
private CameraDevice.StateCallback cameraStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice cameraDevice) {
Log.d(TAG, "onOpend: CAMERA OPENED");
camera = cameraDevice;
getFrames();
}
@Override
public void onDisconnected(CameraDevice cameraDevice) {
Log.d(TAG, "onDisconnected: CAMERA DISCONNECTED");
cameraDevice.close();
camera = null;
}
@Override
public void onError(CameraDevice cameraDevice, int i) {
Log.d(TAG, "onError: CAMERA ERROR");
cameraDevice.close();
camera = null;
}
};
private CameraCaptureSession.StateCallback captureSessionStateCallback = new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession cameraCaptureSession) {
Log.d(TAG, "onConfigured: build request and capture");
try {
CaptureRequest.Builder requestBuilder = cameraCaptureSession.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
requestBuilder.addTarget(imageReaderSurface);
cameraCaptureSession.capture(requestBuilder.build(), null, handler);
} catch (CameraAccessException e) {
Log.d(TAG, "onConfigured: CANT CREATE CAPTURE REQUEST");
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
Log.d(TAG, "onConfiguredFailed: CANT CONFIGURE CAMERA");
}
};
private ImageReader.OnImageAvailableListener imageReaderListener = new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader imageReader) {
Log.d(TAG, "onImageAvailable: IMAGE AVAILABLE");
Image image = imageReader.acquireLatestImage();
int imgFormat = image.getFormat();
ByteBuffer pixelArray1 = image.getPlanes()[0].getBuffer();
int pixelStride = image.getPlanes()[0].getPixelStride();
int rowStride = image.getPlanes()[0].getRowStride();
int rowPadding = rowStride - pixelStride * 640;
Bitmap bitmap = Bitmap.createBitmap(640 + rowPadding/pixelStride, 480, Bitmap.Config.RGB_565);
bitmap.copyPixelsFromBuffer(pixelArray1);
imageView.setImageBitmap(bitmap);
image.close();
}
};
/**
* Sets the cameraId with the front camera id and sets imageReader properties.
*/
public void setupCamera(int width, int height) {
imageReader = ImageReader.newInstance(width, height, ImageFormat.RGB_565, 30);
CameraManager cameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);
try {
for (String allCamerasId : cameraManager.getCameraIdList()) {
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(allCamerasId);
if (cameraCharacteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT) {
continue;
}
cameraId = allCamerasId;
Log.d(TAG, "setupCamera: CameraId is: " + cameraId);
return;
}
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* Connects to the front facing camera.
* After the connection to the camera, the onOpened callback method will be invoked.
*/
public void connectCamera() {
CameraManager cameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);
try {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
Log.d(TAG, "CANT OPEN CAMERA");
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
cameraManager.openCamera(cameraId, cameraStateCallback, handler);
Log.d(TAG, "connectCamera: CAMERA OPENED!");
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* Build the captureSessionRequest and start in repeat.
*/
public void getFrames() {
Log.d(TAG, "getFrames: CREATE CAPTURE SESSION");
imageReaderSurface = imageReader.getSurface();
List<Surface> surfaceList = new ArrayList<>();
surfaceList.add(imageReaderSurface);
try {
camera.createCaptureSession(surfaceList, captureSessionStateCallback, handler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
public void startBackgroundThread() {
handlerThread = new HandlerThread("CameraImageReaderActivity");
handlerThread.start();
handler = new Handler(handlerThread.getLooper());
}
public void stopBackgroundThread() {
handlerThread.quitSafely();
try {
handlerThread.join();
handlerThread = null;
handler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void closeCamera() {
if (camera != null) {
camera.close();
camera = null;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_image_reader);
imageView = (ImageView) findViewById(R.id.imageView);
setupCamera(640, 480);
connectCamera();
}
@Override
protected void onPause() {
closeCamera();
startBackgroundThread();
super.onPause();
}
@Override
protected void onResume() {
super.onResume();
startBackgroundThread();
//connectCamera();
}
And the (relevant) logcat:
03-22 14:27:32.900 18806-18806/com.example.noamm_000.talkwithcompviawifi D/CAMERA_IMAGE_READY:: setupCamera: CameraId is: 0
03-22 14:27:32.904 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value mw_continuous-picture
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value emboss
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value sketch
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value neon
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value asd
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value backlight
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value flowers
03-22 14:27:32.905 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value AR
03-22 14:27:32.912 18806-18806/com.example.noamm_000.talkwithcompviawifi I/CameraManager: Using legacy camera HAL.
03-22 14:27:33.685 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value mw_continuous-picture
03-22 14:27:33.685 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value emboss
03-22 14:27:33.685 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value sketch
03-22 14:27:33.685 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value neon
03-22 14:27:33.686 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value asd
03-22 14:27:33.686 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value backlight
03-22 14:27:33.686 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value flowers
03-22 14:27:33.686 18806-18806/com.example.noamm_000.talkwithcompviawifi W/ArrayUtils: Ignoring invalid value AR
03-22 14:27:33.702 18806-18806/com.example.noamm_000.talkwithcompviawifi D/CAMERA_IMAGE_READY:: connectCamera: CAMERA OPENED!
03-22 14:27:33.719 18806-18806/com.example.noamm_000.talkwithcompviawifi I/Choreographer: Skipped 56 frames! The application may be doing too much work on its main thread.
03-22 14:27:33.787 18806-18806/com.example.noamm_000.talkwithcompviawifi D/CAMERA_IMAGE_READY:: onOpend: CAMERA OPENED
03-22 14:27:33.787 18806-18806/com.example.noamm_000.talkwithcompviawifi D/CAMERA_IMAGE_READY:: getFrames: CREATE CAPTURE SESSION
03-22 14:27:33.789 18806-18806/com.example.noamm_000.talkwithcompviawifi I/CameraDeviceState: Legacy camera service transitioning to state CONFIGURING
03-22 14:27:33.789 18806-19149/com.example.noamm_000.talkwithcompviawifi I/RequestThread-0: Configure outputs: 1 surfaces configured.
03-22 14:27:33.790 18806-19149/com.example.noamm_000.talkwithcompviawifi D/Camera: app passed NULL surface
03-22 14:27:33.838 18806-18806/com.example.noamm_000.talkwithcompviawifi I/CameraDeviceState: Legacy camera service transitioning to state IDLE
03-22 14:27:33.843 18806-19150/com.example.noamm_000.talkwithcompviawifi D/CAMERA_IMAGE_READY:: onConfigured: build request and capture
03-22 14:27:33.874 18806-19149/com.example.noamm_000.talkwithcompviawifi W/LegacyRequestMapper: convertRequestMetadata - control.awbRegions setting is not supported, ignoring value
03-22 14:27:33.875 18806-19149/com.example.noamm_000.talkwithcompviawifi W/LegacyRequestMapper: Only received metering rectangles with weight 0.
03-22 14:27:33.875 18806-19149/com.example.noamm_000.talkwithcompviawifi W/LegacyRequestMapper: Only received metering rectangles with weight 0.
03-22 14:27:34.070 18806-18806/com.example.noamm_000.talkwithcompviawifi I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@13c07070 time:331143683
03-22 14:27:34.317 18806-19155/com.example.noamm_000.talkwithcompviawifi I/CameraDeviceState: Legacy camera service transitioning to state CAPTURING
03-22 14:27:34.353 18806-19149/com.example.noamm_000.talkwithcompviawifi I/CameraDeviceState: Legacy camera service transitioning to state IDLE
03-22 14:27:34.403 18806-18806/com.example.noamm_000.talkwithcompviawifi D/BubblePopupHelper: isShowingBubblePopup : false
03-22 14:27:34.403 18806-18806/com.example.noamm_000.talkwithcompviawifi D/BubblePopupHelper: isShowingBubblePopup : false
03-22 14:27:34.404 18806-18806/com.example.noamm_000.talkwithcompviawifi D/BubblePopupHelper: isShowingBubblePopup : false
03-22 14:27:34.404 18806-18806/com.example.noamm_000.talkwithcompviawifi D/BubblePopupHelper: isShowingBubblePopup : false
03-22 14:28:07.684 18806-18823/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.684 18806-18822/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.684 18806-19184/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.685 18806-18823/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.685 18806-18822/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.685 18806-19184/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.686 18806-18823/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
03-22 14:28:07.686 18806-18822/com.example.noamm_000.talkwithcompviawifi E/BufferQueueProducer: [unnamed-18806-1] cancelBuffer: BufferQueue has been abandoned
Thanks, Noam
回答1:
Try this way better to handle it in background thread.
public void onImageAvailable(ImageReader reader) {
new ImageSaver(reader.acquireLatestImage());
}
private class ImageSaver implements Runnable {
private final Image mImage;
public ImageSaver(Image image) {
mImage = image;
}
@Override
public void run() {
File mImageFileName = null;
if (mImage != null) {
ByteBuffer byteBuffer = mImage.getPlanes()[0].getBuffer();
byte[] bytes = new byte[byteBuffer.remaining()];
byteBuffer.get(bytes);
FileOutputStream fileOutputStream = null;
try {
mImageFileName = createImageFileName();
fileOutputStream = new FileOutputStream(mImageFileName);
fileOutputStream.write(bytes);
} catch (IOException e) {
e.printStackTrace();
} finally {
mImage.close();
if (mImageFileName != null) {
Intent mediaStoreUpdateIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
mediaStoreUpdateIntent.setData(Uri.fromFile(mImageFileName));
sendBroadcast(mediaStoreUpdateIntent);
loadImageFromStorage(mImageFileName);
}
if (fileOutputStream != null) {
try {
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
private void loadImageFromStorage(File mImageFileName) {
imageView.setImageBitmap(BitmapFactory.decodeFile(mImageFileName.getAbsolutePath()));
}
}
private File createImageFileName() throws IOException {
String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String prepend = "IMAGE_" + timestamp + "_";
File imageFile = File.createTempFile(prepend, ".jpg", createImageFolder());
return imageFile;
}
private File createImageFolder() {
File imageFile = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File mImageFolder = new File(imageFile, "myFolder");
if (!mImageFolder.exists()) {
mImageFolder.mkdirs();
}
return mImageFolder;
}
回答2:
As this question is a bit old, not sure if it's still topical, but I'll try to answer.
You are creating an instance of ImageRader, an ImageReader.OnImageAvailableListener, but not assigning your listener to the imageReader instance you have.
In your setupCamera method, after instantiating a new ImageReader, set the listener to it:
/**
* Sets the cameraId with the front camera id and sets imageReader properties.
*/
public void setupCamera(int width, int height) {
imageReader = ImageReader.newInstance(width, height, ImageFormat.RGB_565, 30);
// this line is missing
imageReader.setOnImageAvailableListener(imageReaderListener, handler);
...
Hope this helps you, or someone else trying out your code as a sample.
回答3:
Is RGB_565 listed as a supported format for this camera device, from CameraManager.getCameraCharacteristics(id).get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputFormats()?
If not, this won't generally work, though it should give you a session creation failure. The only formats that are guaranteed to be supported are ImageFormat.JPEG and ImageFormat.YUV_420_888.
The former is probably easier to deal with (though a bit less efficient) - copy the JPEG plane[0] ByteBuffer into a byte[] and use BitmapFactory.decodeByteArray() to create a bitmap from it to display.
For your specific case, though, you don't seem to ever be calling imageReader.setOnImageAvailableListener(imageReaderListener), so there's no way you'll ever get a notice about a captured buffer.
Edit: In addition, the first few images you receive from the camera may be badly exposed (could be all black if you're in a poorly lit location) and have poor white balance, focus, etc. You need to let the camera run for a few frames so that it can adjust auto-exposure/focus/etc to correct values, before you capture the final image.
Generally, using a repeating request with TEMPLATE_PREVIEW and waiting until you see at least CONTROL_AE_STATE_CONVERGED in the capture results would be a good idea; that'll still leave focus in potentially a poor state, but whether you want to deal with focus depends on the use case and output resolution.
来源：https://stackoverflow.com/questions/42951837/using-camera2-api-to-get-single-image-and-display-it-with-imageview