CameraSource.java 文件源码

/**
 * Opens the camera and starts sending preview frames to the underlying detector.  The supplied
 * surface holder is used for the preview so frames can be displayed to the user.
 *
 * @param surfaceHolder the surface holder to use for the preview frames
 * @throws IOException if the supplied surface holder could not be used as the preview display
 */
@RequiresPermission(Manifest.permission.CAMERA)
public CameraSource start(SurfaceHolder surfaceHolder) throws IOException {
    synchronized (mCameraLock) {
        if (mCamera != null) {
            return this;
        }

        mCamera = createCamera();
        mCamera.setPreviewDisplay(surfaceHolder);
        mCamera.startPreview();

        mProcessingThread = new Thread(mFrameProcessor);
        mFrameProcessor.setActive(true);
        mProcessingThread.start();
    }
    return this;
}