实施OrientationEventListener帮助相机问题，而CameraInfo？ [英] implementing OrientationEventListener to help camera issues without CameraInfo?

问题描述

我需要实现 OrientationEventListener 让相机正常工作。谷歌发布 onOrientationChanged 的样本实现看起来像这样：

I need to implement an OrientationEventListener to get the camera working correctly. Google posted a sample implementation of onOrientationChanged that looks like this:

@Override
    public void onOrientationChanged(int orientation) {
        if (orientation == ORIENTATION_UNKNOWN) return;
     android.hardware.Camera.CameraInfo info =
            new android.hardware.Camera.CameraInfo();
     android.hardware.Camera.getCameraInfo(cameraId, info);
     orientation = (orientation + 45) / 90 * 90;
     int rotation = 0;
     if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
         rotation = (info.orientation - orientation + 360) % 360;
     } else {  // back-facing camera
         rotation = (info.orientation + orientation) % 360;
     }
     mParameters.setRotation(rotation);
    }

但我反对建设API级别8，所以我没有 CameraInfo 。我怎么能完成类似的事情上面，而不 CameraInfo

But I'm building against API level 8, so I don't have CameraInfo. How can I accomplish a similar thing as the above without CameraInfo?

推荐答案

虽然方向的变化，我觉得我也必须改变相机preVIEW来搭配，如果你想在旋转全屏图像，所以我使用类似的方法，但在像这样一个镜头面视图onLayout（）方法：

Although the orientation changes, I find I have to also change the camera preview to match, if you want full-screen images on rotation, so I use a similar method but in the onLayout() method of a camera surface view like so:

/*
 * This class provides the surface for the camera.
 */
public class CameraSurfaceView extends ViewGroup implements SurfaceHolder.Callback
{

@Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom)
    {
        if (changed)
        {               

            final int width = right - left;
            final int height = bottom - top;

            int previewWidth = width;
            int previewHeight = height;
            if (mPreviewSize != null)
            {
                Display display = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

                switch (display.getRotation())
                {
                    case Surface.ROTATION_0:
                        previewWidth = mPreviewSize.height;
                        previewHeight = mPreviewSize.width;
                        mCamera.setDisplayOrientation(90);
                        break;
                    case Surface.ROTATION_90:
                        previewWidth = mPreviewSize.width;
                        previewHeight = mPreviewSize.height;
                        break;
                    case Surface.ROTATION_180:
                        previewWidth = mPreviewSize.height;
                        previewHeight = mPreviewSize.width;
                        break;
                    case Surface.ROTATION_270:
                        previewWidth = mPreviewSize.width;
                        previewHeight = mPreviewSize.height;
                        mCamera.setDisplayOrientation(180);
                        break;
                }                                    
            }

            final int scaledChildHeight = previewHeight * width / previewWidth;

            cameraView.layout(0, height - scaledChildHeight, width, height);

        }
    }

}

这很适合我使用的Andr​​oid API 8（Android 2.2的）的HTC Desire的。

This has worked for me on an HTC Desire using Android API 8 (Android 2.2).

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