我正在尝试制作相机预览应用。我打电话的时候
session.setRepeatingRequest(captureRequestBuilder.build(), null, backgroundHandler)
我收到此错误：
E/HandlerDispatcher: IllegalArgumentException while invoking public abstract void android.hardware.camera2.CameraCaptureSession$StateCallback.onConfigured(android.hardware.camera2.CameraCaptureSession)
java.lang.IllegalArgumentException: Each request must have at least one Surface target
at android.hardware.camera2.impl.CameraDeviceImpl.submitCaptureRequest(CameraDeviceImpl.java:934)
at android.hardware.camera2.impl.CameraDeviceImpl.setRepeatingRequest(CameraDeviceImpl.java:993)
at android.hardware.camera2.impl.CameraCaptureSessionImpl.setRepeatingRequest(CameraCaptureSessionImpl.java:239)
at anthe.rwca.org.robocup19.MainActivity$3.onConfigured(MainActivity.java:147)
at java.lang.reflect.Method.invoke(Native Method)
at android.hardware.camera2.dispatch.InvokeDispatcher.dispatch(InvokeDispatcher.java:39)
at android.hardware.camera2.dispatch.HandlerDispatcher$1.run(HandlerDispatcher.java:65)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.os.HandlerThread.run(HandlerThread.java:65)
这是我的代码：
CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;
createCaptureSession();
}
@Override
public void onDisconnected(@NonNull CameraDevice camera) {
}
@Override
public void onError(@NonNull CameraDevice camera, int error) {
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textureView = findViewById(R.id.textureView);
}
@Override
protected void onResume() {
super.onResume();
textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
openBackgroundHandler();
setupCamera();
openCamera();
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
}
});
}
@Override
protected void onPause() {
super.onPause();
closeBackgroundHandler();
}
private void setupCamera() {
cameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);
try {
cameraIDs = cameraManager.getCameraIdList();
cameraID = cameraIDs[0];
Log.i(TAG, String.valueOf(cameraIDs.length));
Log.i(TAG, cameraID);
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraID);
StreamConfigurationMap streamConfigurationMap = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
size = streamConfigurationMap.getOutputSizes(SurfaceTexture.class)[0];
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@SuppressLint("MissingPermission")
private void openCamera() {
try {
cameraManager.openCamera(cameraID, stateCallback, backgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void openBackgroundHandler() {
handlerThread = new HandlerThread("camera_app");
handlerThread.start();
backgroundHandler = new Handler(handlerThread.getLooper());
}
private void closeBackgroundHandler() {
handlerThread.quit();
handlerThread = null;
backgroundHandler = null;
}
private void createCaptureSession() {
SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
surfaceTexture.setDefaultBufferSize(size.getWidth(), size.getHeight());
Surface surface = new Surface(surfaceTexture);
try {
cameraDevice.createCaptureSession(Collections.singletonList(surface), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
try {
CaptureRequest.Builder captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
session.setRepeatingRequest(captureRequestBuilder.build(), null, backgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
}
}, backgroundHandler);
} catch (CameraAccessException e1) {
e1.printStackTrace();
}
}
我是Camera2 API的新手，所以我不知道错误意味着什么。我在互联网上环顾四周，但我找不到类似的问题。
我还想知道如何在位图或nv21字节数组中获取预览帧，因此我可以对其进行一些图像处理并将处理后的图像显示为位图（或者有一种方法可以直接应用某些图像处理到预览的框架）？先感谢您。
看看Camera2Basic样本，以帮助解决一般情况。
在这种特殊情况下 - 捕获会话可以有多个目标输出Surfaces（一个用于预览，一个用于静态捕获JPEG）。每个捕获请求都可以针对这些输出的任何子集（因此重复请求以预览输出为目标，同时仍然捕获目标JPEG输出等）。
因此，您的捕获请求需要添加一个或多个Surface作为目标，而Surfaces必须是会话创建中包含的Surface之一。
由于您的会话中只有一个Surface，因此只需添加
captureRequestBuilder.addTarget(surface)
在setRepeatingRequest调用之前。
如果要获取YUV数据的Java ByteBuffer，您还可以为会话和捕获请求添加ImageReader作为输出目标。请注意，只保证支持YUV_420_888灵活的YUV格式，因此如果您真的需要NV21布局中的某些东西，您必须手动调整它（在任何给定的设备上，YUV_420_888可能是引擎盖下的NV21，但不能保证关于那个）。