这是我的 cameraPreview 我在 SurfaceChanged 中设置了监听器。我可以在应用程序中看到摄像头——但从未调用过 OnPreviewFrame。这是大部分代码
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private static boolean DEBUGGING = true;
private static final String LOG_TAG = "CameraPreviewSample";
private static final String CAMERA_PARAM_ORIENTATION = "orientation";
private static final String CAMERA_PARAM_LANDSCAPE = "landscape";
private static final String CAMERA_PARAM_PORTRAIT = "portrait";
protected Activity mActivity;
private SurfaceHolder mHolder;
protected Camera mCamera;
protected List<Camera.Size> mPreviewSizeList;
protected List<Camera.Size> mPictureSizeList;
protected Camera.Size mPreviewSize;
protected Camera.Size mPictureSize;
private int mSurfaceChangedCallDepth = 0;
private int mCameraId;
private LayoutMode mLayoutMode;
private int mCenterPosX = -1;
private int mCenterPosY;
public Mat frame1=null;
public Mat frame2=null;
PreviewReadyCallback mPreviewReadyCallback = null;
//////Alon
public static int SENSITIVITY_VALUE = 20;
public static int BLUR_SIZE = 10;
public Rect objectBoundingRectangle = new Rect(0, 0, 0, 0);
double ballAverage = 131.5;
int frameCounter = 0;
public static enum LayoutMode {
FitToParent, // Scale to the size that no side is larger than the parent
NoBlank // Scale to the size that no side is smaller than the parent
};
public interface PreviewReadyCallback {
public void onPreviewReady();
}
/**
* State flag: true when surface's layout size is set and surfaceChanged()
* process has not been completed.
*/
protected boolean mSurfaceConfiguring = false;
public CameraPreview(Activity activity, int cameraId, LayoutMode mode) {
super(activity); // Always necessary
mActivity = activity;
mLayoutMode = mode;
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
if (Camera.getNumberOfCameras() > cameraId) {
mCameraId = cameraId;
} else {
mCameraId = 0;
}
} else {
mCameraId = 0;
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
mCamera = Camera.open(mCameraId);
} else {
mCamera = Camera.open();
}
Camera.Parameters cameraParams = mCamera.getParameters();
mPreviewSizeList = cameraParams.getSupportedPreviewSizes();
mPictureSizeList = cameraParams.getSupportedPictureSizes();
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
mCamera.setPreviewDisplay(mHolder);
} catch (IOException e) {
mCamera.release();
mCamera = null;
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
mSurfaceChangedCallDepth++;
doSurfaceChanged(width, height);
mSurfaceChangedCallDepth--;
}
private void doSurfaceChanged(int width, int height) {
mCamera.stopPreview();
Camera.Parameters cameraParams = mCamera.getParameters();
boolean portrait = isPortrait();
// The code in this if-statement is prevented from executed again when surfaceChanged is
// called again due to the change of the layout size in this if-statement.
if (!mSurfaceConfiguring) {
Camera.Size previewSize = determinePreviewSize(portrait, width, height);
Camera.Size pictureSize = determinePictureSize(previewSize);
if (DEBUGGING) { Log.v(LOG_TAG, "Desired Preview Size - w: " + width + ", h: " + height); }
mPreviewSize = previewSize;
mPictureSize = pictureSize;
mSurfaceConfiguring = adjustSurfaceLayoutSize(previewSize, portrait, width, height);
// Continue executing this method if this method is called recursively.
// Recursive call of surfaceChanged is very special case, which is a path from
// the catch clause at the end of this method.
// The later part of this method should be executed as well in the recursive
// invocation of this method, because the layout change made in this recursive
// call will not trigger another invocation of this method.
if (mSurfaceConfiguring && (mSurfaceChangedCallDepth <= 1)) {
return;
}
}
configureCameraParameters(cameraParams, portrait);
mSurfaceConfiguring = false;
try {
mCamera.startPreview();
} catch (Exception e) {
Log.w(LOG_TAG, "Failed to start preview: " + e.getMessage());
// Remove failed size
mPreviewSizeList.remove(mPreviewSize);
mPreviewSize = null;
// Reconfigure
if (mPreviewSizeList.size() > 0) { // prevent infinite loop
surfaceChanged(null, 0, width, height);
} else {
Toast.makeText(mActivity, "Can't start preview", Toast.LENGTH_LONG).show();
Log.w(LOG_TAG, "Gave up starting preview");
}
}
if (null != mPreviewReadyCallback) {
mPreviewReadyCallback.onPreviewReady();
}
//////////////////////////Alon
if (mCamera == null) {
return;
}
mCamera.setPreviewCallback(new PreviewCallback() {
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Mat frame = Byte_to_Mat(data);
if(frame1==null) {
frame1 = frame;
}
else
{
if (frame2 == null)
{
frame2 = frame;
}
else
{
frame1 = frame2;
frame2 = frame;
}
detectBall(frame1,frame2);
}
}
});
}
public Mat Byte_to_Mat(byte[] data) {
Mat jpegData = new Mat(1, data.length, CvType.CV_8UC1);
jpegData.put(0, 0, data);
return jpegData;
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
stop();
}
public void stop() {
if (null == mCamera) {
return;
}
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
public boolean isPortrait() {
return (mActivity.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT);
}
public void setOneShotPreviewCallback(PreviewCallback callback) {
if (null == mCamera) {
return;
}
mCamera.setOneShotPreviewCallback(callback);
}
public void setPreviewCallback(PreviewCallback callback) {
if (null == mCamera) {
return;
}
mCamera.setPreviewCallback(callback);
}
public Camera.Size getPreviewSize() {
return mPreviewSize;
}
public void setOnPreviewReady(PreviewReadyCallback cb) {
mPreviewReadyCallback = cb;
}
我也尝试在构造函数中设置 setPreviewCallback 。并且还在 Surface Created 上。有人知道这个的来源吗？