我一直在关注 camera2 文档，尝试使用 ImageReader 实现非预览相机，但是当我到达 cameraDevice.createCaptureSession(outputs, mccsStateCallback, cameraHandler); 时，cameraDevice 对象为空，即使我确定它应该已在 CameraCaptureSession.StateCallback 事件监听器中分配(这也没有被触发，因为 CameraCaptureSession 本身为空)。要么我完全错了，要么我错过了一些大事。这是我的代码:
private CameraDevice cameraDevice;
private String cameraId;
private Handler cameraHandler = new Handler();
private CameraCharacteristics cameraCharacteristics;
private ImageReader jpgReader;
Bitmap bitmap;
private Handler imgHandler = new Handler();
private CameraCaptureSession mSession;
private CameraManager cameraManager;
private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;
}
@Override
public void onDisconnected(@NonNull CameraDevice camera) {
cameraDevice.close();
}
@Override
public void onError(@NonNull CameraDevice camera, int error) {
cameraDevice.close();
cameraDevice = null;
}
};
OnImageAvailableListener imageAvailableListener = new OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
Image image = reader.acquireLatestImage();
Image.Plane[] planes = image.getPlanes();
Buffer buffer = planes[0].getBuffer().rewind();
bitmap = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
bitmap.copyPixelsFromBuffer(buffer);
mFaceOverlayView.setBitmap(bitmap);
}
};
private CameraCaptureSession.StateCallback mccsStateCallback = new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
try {
if (PackageManager.PERMISSION_GRANTED == ContextCompat.checkSelfPermission(getBaseContext(), android.Manifest.permission.CAMERA)) {
mSession = session;
CaptureRequest.Builder request = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
request.addTarget(jpgReader.getSurface());
mSession.setRepeatingRequest(request.build(), new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
}
}, null);
cameraManager.openCamera(cameraId, mStateCallback, cameraHandler);
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session) {
}
};
private void initialiseCamera() {
cameraManager = (CameraManager) FilesPlayer.this.getSystemService(Context.CAMERA_SERVICE);
try {
cameraId = getFrontFacingCameraId(cameraManager);
if (PackageManager.PERMISSION_GRANTED == ContextCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA)) {
cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);
StreamConfigurationMap streamConfigurationMap = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
android.util.Size[] jpegSizes = streamConfigurationMap.getOutputSizes(ImageFormat.JPEG);
Size biggestSize = new Size(0, 0);
for (Size size : jpegSizes) {
if (size.getHeight() >= biggestSize.getHeight() && size.getWidth() >= biggestSize.getWidth()) {
biggestSize = size;
}
}
jpgReader = ImageReader.newInstance(biggestSize.getWidth(), biggestSize.getHeight(), ImageFormat.JPEG, 1);
jpgReader.setOnImageAvailableListener(imageAvailableListener, imgHandler);
List<Surface> outputs = Arrays.asList(jpgReader.getSurface());
cameraDevice.createCaptureSession(outputs, mccsStateCallback, cameraHandler);
}
else{
Log.d("NOOO","NOOOO");
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
private String getFrontFacingCameraId(CameraManager cameraManager) {
try {
for (String id : cameraManager.getCameraIdList()) {
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(id);
Integer cameraOrientation = cameraCharacteristics.get(CameraCharacteristics.LENS_FACING);
if (cameraOrientation != null && cameraOrientation == CameraMetadata.LENS_FACING_FRONT) {
return id;
}
}
} catch (CameraAccessException ex) {
ex.printStackTrace();
}
return null;
}
编辑: 我设法通过将
cameraManager.openCamera(cameraId,mStateCallback,cameraHandler); 放在 cameraDevice.createCaptureSession(outputs, mccsStateCallback, cameraHandler); 中的 initialiseCamera() 之前使 CameraDevice 自行分配。现在我遇到了一个问题，即相机输出没有被定向到 ImageReader 的表面，并且我在控制台中收到一个错误，说
E/Surface: getSlotFromBufferLocked: unknown buffer: 0xa1ae7000 。 最佳答案
这是一个快速说明。
请务必在 Manifest 中包含权限。还要确保用户可以通过 ActivityCompact 和 ContextCompact 向应用授予权限。在 Android 6.0 及更高版本上，用户也在运行时授予权限。请参阅文档 here 。
// Here, thisActivity is the current activity
if (ContextCompat.checkSelfPermission(thisActivity,
Manifest.permission.READ_CONTACTS)
!= PackageManager.PERMISSION_GRANTED) {
// Permission is not granted
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(thisActivity,
Manifest.permission.READ_CONTACTS)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
} else {
// No explanation needed; request the permission
ActivityCompat.requestPermissions(thisActivity,
new String[]{Manifest.permission.READ_CONTACTS},
MY_PERMISSIONS_REQUEST_READ_CONTACTS);
// MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
// app-defined int constant. The callback method gets the
// result of the request.
}
} else {
// Permission has already been granted
}
关于android - 如何让 CameraDevice 在 camera2 中工作？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/40119757/