android - 将 Camera SurfaceView 旋转为纵向

Question

我查阅了一些关于使用表面 View 更改相机方向的帖子，但我从以下示例中获取了我的代码:

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

提供维度的函数看起来像这样......

    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，当我改变设备的方向时，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(通常是手机纵向，平板电脑横向)
2. 设备的当前 UI 方向(纵向、横向或各自的反方向)
3. 有问题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 的文档有关于如何正确处理这个问题的示例代码。我在这里复制它:

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)后调用此函数。