Question

我在我的应用中使用条形码扫描仪。在某些移动设备中，它提供运行时异常无法连接到摄像机。

以下是我用于相机的代码

 /**
 * Opens the camera and applies the user settings.
 *
 * @throws RuntimeException if the method fails
 */
@SuppressLint("InlinedApi")
private Camera createCamera() {
    int requestedCameraId = getIdForRequestedCamera(mFacing);
    if (requestedCameraId == -1) {
        throw new RuntimeException("Could not find requested camera.");
    }
    Camera camera = Camera.open(requestedCameraId);

    SizePair sizePair = selectSizePair(camera, mRequestedPreviewWidth, mRequestedPreviewHeight);
    if (sizePair == null) {
        throw new RuntimeException("Could not find suitable preview size.");
    }
    Size pictureSize = sizePair.pictureSize();
    mPreviewSize = sizePair.previewSize();

    int[] previewFpsRange = selectPreviewFpsRange(camera, mRequestedFps);
    if (previewFpsRange == null) {
        throw new RuntimeException("Could not find suitable preview frames per second range.");
    }

    Camera.Parameters parameters = camera.getParameters();

    if (pictureSize != null) {
        parameters.setPictureSize(pictureSize.getWidth(), pictureSize.getHeight());
    }

    parameters.setPreviewSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
    parameters.setPreviewFpsRange(
            previewFpsRange[Camera.Parameters.PREVIEW_FPS_MIN_INDEX],
            previewFpsRange[Camera.Parameters.PREVIEW_FPS_MAX_INDEX]);
    parameters.setPreviewFormat(ImageFormat.NV21);

    setRotation(camera, parameters, requestedCameraId);

    if (mFocusMode != null) {
        if (parameters.getSupportedFocusModes().contains(
                mFocusMode)) {
            parameters.setFocusMode(mFocusMode);
        } else {
            Log.i(TAG, "Camera focus mode: " + mFocusMode + " is not supported on this device.");
        }
    }

    // setting mFocusMode to the one set in the params
    mFocusMode = parameters.getFocusMode();

    if (mFlashMode != null) {
        if (parameters.getSupportedFlashModes() != null) {
            if (parameters.getSupportedFlashModes().contains(
                    mFlashMode)) {
                parameters.setFlashMode(mFlashMode);
            } else {
                Log.i(TAG, "Camera flash mode: " + mFlashMode + " is not supported on this device.");
            }
        }
    }

    // setting mFlashMode to the one set in the params
    mFlashMode = parameters.getFlashMode();

    camera.setParameters(parameters);

    // Four frame buffers are needed for working with the camera:
    //
    //   one for the frame that is currently being executed upon in doing detection
    //   one for the next pending frame to process immediately upon completing detection
    //   two for the frames that the camera uses to populate future preview images
    camera.setPreviewCallbackWithBuffer(new CameraPreviewCallback());
    camera.addCallbackBuffer(createPreviewBuffer(mPreviewSize));
    camera.addCallbackBuffer(createPreviewBuffer(mPreviewSize));
    camera.addCallbackBuffer(createPreviewBuffer(mPreviewSize));
    camera.addCallbackBuffer(createPreviewBuffer(mPreviewSize));

    return camera;
}

   * Stops the camera.
 */
@Override
protected void onPause() {
    super.onPause();
    if (mPreview != null) {
        mPreview.stop();
    }
}

/**
 * Releases the resources associated with the camera source, the associated detectors, and the
 * rest of the processing pipeline.
 */
@Override
protected void onDestroy() {
    super.onDestroy();
    if (mPreview != null) {
        mPreview.release();
    }

}

    /**
 * Restarts the camera.
 */
@Override
protected void onResume() {
    super.onResume();
        startCameraSource();
}

我得到的运行时异常是

    java.lang.RuntimeException: Fail to connect to camera service
at android.hardware.Camera.<init>(Camera.java:532)
at android.hardware.Camera.open(Camera.java:360)

任何帮助关于这个问题，因为在某些设备中它正在工作但在某些设备中它不起作用我无法解决问题。

Answer 1

在访问相机之前，请务必检查相机是否可用。

    private Camera mCamera;     
    /**
     * Opens the camera and applies the user settings.
     *
     * @throws RuntimeException if the method fails
     */
    @SuppressLint("InlinedApi")
    private Camera createCamera() {
       int requestedCameraId = getIdForRequestedCamera(mFacing);
       if (requestedCameraId == -1) {
           throw new RuntimeException("Could not find requested camera.");
       }

       if (mCamera != null){
          mCamera.release();
          mCamera = null;
       }

       mCamera= Camera.open(requestedCameraId);

       if(camera == null){
          Toast.makeText(mContext, "Camera service is not available currently.", Toast.LENGTH_LONG.show())    
            }
           //....
       }
     }

在onDestroy()之前重新使用相机。

/**
 * Releases the resources associated with the camera source, the associated detectors, and the
 * rest of the processing pipeline.
 */
@Override
protected void onDestroy() {
    super.onDestroy();
    if (mPreview != null) {
        mPreview.release();
        mCamera.release();
        mCamera = null;
}

运行时异常无法连接到某些设备中的摄像头服务

1 个答案: