将相机 SurfaceView 旋转为纵向

Question

我查找了一些关于使用表面视图更改相机方向的帖子，但我从以下示例中获取了代码：

http://developer.android.com /resources/samples/ApiDemos/src/com/example/android/apis/graphics/CameraPreview.html

提供尺寸的函数如下所示...

    private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }

我的问题是，当我更改设备上，预览图片保持横向。我尝试设置相机的方向，但这导致了非常奇怪的结果。有谁知道我需要更改什么才能正确旋转？

Answer 1

正确调整相机预览方向的代码有点复杂，因为它必须考虑

1. 传感器的相对方向和设备的“自然”方向（通常是手机的纵向，平板电脑的横向）
2. 当前的 UI设备的方向（纵向、横向或各自的反向）
3. 所涉及的摄像头是前置摄像头还是后置摄像头（因为前置预览流是水平镜像的）

Camera.setDisplayOrientation 有有关如何正确处理此问题的示例代码。我在这里重现它：

public static void setCameraDisplayOrientation(Activity activity,
     int cameraId, android.hardware.Camera camera) {

   android.hardware.Camera.CameraInfo info = 
       new android.hardware.Camera.CameraInfo();

   android.hardware.Camera.getCameraInfo(cameraId, info);

   int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
   int degrees = 0;

   switch (rotation) {
       case Surface.ROTATION_0: degrees = 0; break;
       case Surface.ROTATION_90: degrees = 90; break;
       case Surface.ROTATION_180: degrees = 180; break;
       case Surface.ROTATION_270: degrees = 270; break;
   }

   int result;
   if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
       result = (info.orientation + degrees) % 360;
       result = (360 - result) % 360;  // compensate the mirror
   } else {  // back-facing
       result = (info.orientation - degrees + 360) % 360;
   }
   camera.setDisplayOrientation(result);
}

在绘制 UI（onSurfaceChanged 将用作指示器）或设备 UI 旋转（onConfigurationChanged 将用作指示器）后调用此方法。

Answer 2

我能够通过将以下代码放入 onSurfaceChanged() 中来解决旋转问题：

    if (mHolder.getSurface() == null) {
        // preview surface does not exist
        return;
    }

    // stop preview before making changes
    try {
        mCamera.stopPreview();
    } catch (Exception e) {
        // ignore: tried to stop a non-existent preview
    }

    // make any resize, rotate or reformatting changes here
    if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) {

        mCamera.setDisplayOrientation(90);

    } else {

        mCamera.setDisplayOrientation(0);

    }
    // start preview with new settings
    try {
        mCamera.setPreviewDisplay(mHolder);
        mCamera.startPreview();

    } catch (Exception e) {
        Log.d(TAG, "Error starting camera preview: " + e.getMessage());
    }

但这产生了另一个问题，或者更好地说，没有解决问题 - 虽然方向正确，但预览图像仍然只占用相同数量的景观景观所做的空间。我最终只是放弃并强制横向：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

在 onCreate() 中并设计了横向布局。祝你好运，我希望有人能解决这个次要问题！

Answer 3

试试这个，但我在 Samsung Galaxy Tab 上试过

public void surfaceCreated(SurfaceHolder holder)
{
   // The Surface has been created, acquire the camera and tell it where to draw.
   mCamera = Camera.open();

   Parameters params = mCamera.getParameters();

   if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE)
   {
    params.set("orientation", "portrait");
    mCamera.setDisplayOrientation(90);
   }

    try
      {
      mCamera.setPreviewDisplay(holder);
      }
      catch (IOException exception)
      {
        mCamera.release();
        mCamera = null;
      }

}

Answer 4

我通过添加以下内容解决了这个问题：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

到 onCreate 事件。

Answer 5

请尝试这个..

@Override
 public void surfaceChanged(SurfaceHolder holder,
                       int format, int width, int height)
{
// TODO Auto-generated method stub

if(previewing)
{
    camera.stopPreview();
    previewing = false;
}
 Camera.Parameters parameters = camera.getParameters();
      Display display = ((WindowManager)getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
   int or=cameraInfo.orientation;
     // You need to choose the most appropriate previewSize for your app
   // .... select one of previewSizes here
           /* parameters.setPreviewSize(previewSize.width, previewSize.height);*/
   if(display.getRotation() == Surface.ROTATION_0)
    {

    camera.setDisplayOrientation(90);
    or=90;
    }

    if(display.getRotation() == Surface.ROTATION_180)
    {
        camera.setDisplayOrientation(270);
    or=270;
    }
    if(display.getRotation() == Surface.ROTATION_270)
    {
        camera.setDisplayOrientation(180);
        or=180;
    }

  parameters.setRotation(or);

  camera.setParameters(parameters);
 try
{
        camera.setPreviewDisplay(cameraSurfaceHolder);
        camera.startPreview();
        previewing = true;
    }
    catch (IOException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Answer 6

好吧，我这样做！

我已经在 surfaceCreated() 方法中以这种方式解决了这个问题，

 public void surfaceCreated(SurfaceHolder holder) {
    try {

        camera = Camera.open();
    } catch (RuntimeException e) {
        System.err.println(e);
        return;
    }
    Camera.Parameters param;
    param = camera.getParameters();
    if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE)
    {
        param.set("orientation", "portrait");
        setCameraDisplayOrientation(this,1,camera);
    }
    camera.setParameters(param);

    try {
        camera.setPreviewDisplay(surfaceHolder);
        camera.startPreview();
    } catch (Exception e) {
        System.err.println(e);
        return;
    }
}

在下面的 3 中添加此方法

 public static void setCameraDisplayOrientation(Activity activity,
                                               int cameraId, android.hardware.Camera camera) {

    android.hardware.Camera.CameraInfo info =
            new android.hardware.Camera.CameraInfo();

    android.hardware.Camera.getCameraInfo(cameraId, info);

    int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
    int degrees = 0;

    switch (rotation) {
        case Surface.ROTATION_0: degrees = 0; break;
        case Surface.ROTATION_90: degrees = 90; break;
        case Surface.ROTATION_180: degrees = 180; break;
        case Surface.ROTATION_270: degrees = 270; break;
    }

    int result;
    if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
        result = (info.orientation + degrees) % 360;
        result = (360 - result) % 360;  // compensate the mirror
    } else {  // back-facing
        result = (info.orientation - degrees + 360) % 360;
    }
    camera.setDisplayOrientation(result);
}

：确保您已添加相机权限以支持活动中的牛轧糖，在此活动调用不要在此活动中调用相机权限，因为 surfacecreated 调用为创建的活动，并且将等待您的许可才能打开相机

Answer 7

仅添加此

mCamera.setDisplayOrientation(90);