相机预览方向为横向，但设备为纵向答案

【问题标题】：Camera preview orientation is in landscape but device is in portrait相机预览方向为横向，但设备为纵向
【发布时间】：2018-11-30 14:53:31
【问题描述】：

camera2 API 中的预览方向有问题。即使设备处于纵向模式，我得到的预览也是横向的。更准确地说，我得到的传感器旋转为 90，因此，传感器数据也被映射为 90。观察结果在模拟器 (Nexus 5) 上。

private void startPreview() {
    SurfaceTexture surfaceTexture = mTextureView.getSurfaceTexture();
    surfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
    Surface previewSurface = new Surface(surfaceTexture);

    try {
        mCaptureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        mCaptureRequestBuilder.addTarget(previewSurface);

        mCameraDevice.createCaptureSession(Arrays.asList(previewSurface),
                new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                try {
                    cameraCaptureSession.setRepeatingRequest(mCaptureRequestBuilder.build(),
                            null, mBackgroundHanlder);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }

}

private void setupCamera(int width, int height) {
    CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        for(String cameraId: cameraManager.getCameraIdList()) {
            CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);
            if (cameraCharacteristics.get(CameraCharacteristics.LENS_FACING)
                    == CameraCharacteristics.LENS_FACING_FRONT) {
                continue;
            }
            StreamConfigurationMap map = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);

            int deviceOrientation = getWindowManager().getDefaultDisplay().getRotation();
            mTotalRotation = sensorToDeviceRotation(cameraCharacteristics, deviceOrientation);
            boolean swapRotation = mTotalRotation == 90 || mTotalRotation == 270;
            int rotatedWidth = width;
            int rotatedHeight = height;

            if (swapRotation) {
                rotatedHeight = width;
                rotatedWidth = height;
            }
            mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), rotatedWidth, rotatedHeight);
            mVideoSize = chooseOptimalSize(map.getOutputSizes(MediaRecorder.class), rotatedWidth, rotatedHeight);

            mcameraId = cameraId;
            return;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

}


private static int sensorToDeviceRotation(CameraCharacteristics cameraCharacteristics, int deviceOrientation) {
    int sensorOrientation = cameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
    deviceOrientation = ORIENTATIONS.get(deviceOrientation);
    return (sensorOrientation+deviceOrientation+360)%360;
}

【问题讨论】：

标签： android android-orientation android-camera2

【解决方案1】：

看起来您实际上并未将旋转变换应用于输出帧。只是交换宽度/高度没有任何作用，因为通常相机只支持横向分辨率。

您需要使用 TextureView 的 getTransform 和 setTransform 函数来添加必要的旋转。

具体来说：

使用 getTransform 读入当前转换
将该变换乘以您根据 UI 方向计算的必要旋转变换
使用 setTransform 将其设置为 TextureView 变换

Camera2Basic 示例应用的代码在这里可能会有所帮助，但我不确定它是否设置为纵向：https://github.com/googlesamples/android-Camera2Basic/blob/master/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java

【讨论】：