Question

我的应用程序使用相机。要以正确的方式显示相机的预览，我必须考虑相对于物理设备方向的活动方向。 I. e。如果活动方向被锁定且永不改变，我不需要采取任何进一步的步骤 - 随着设备的旋转，预览图像将相应地旋转。但是，想象一下我的活动可以改变方向。您旋转设备 - 并预览 - 直到您达到纵向模式（假设它原来是风景），此时活动旋转以适应新的方向。但是预览图像随之旋转，现在它与相机和周围的现实不同步。我必须做的是确定活动方向并相应地旋转图像。

似乎可以使用Display.getRotation()。但显然，它不能：https://groups.google.com/forum/#!topic/android-developers/ij_0QbApKKc

问题是Android API并未解决原点问题。某些平板电脑在正常方向上返回旋转0（横向，音量按钮向上），而其他平板电脑（如我的Nexus 7 2013）则返回1。

我该如何解决这个问题？

Answer 1

您可以使用OrientationEventListener像这样的东西确定方向

    mOrientationEventListener = new OrientationEventListener(context, SensorManager.SENSOR_DELAY_NORMAL) {

            @Override
            public void onOrientationChanged(int orientation) {

                // determine our orientation based on sensor response

                Display display = ((WindowManager)getSystemService(WINDOW_SERVICE)).getDefaultDisplay();                                        

                if (display.getOrientation() == Surface.ROTATION_0) {   // landscape oriented devices
                    isLandscapeOriented = true;
                    if (orientation >= 315 || orientation < 45) {
                        if (mOrientation != ORIENTATION_LANDSCAPE_NORMAL) {                         
                            mOrientation = ORIENTATION_LANDSCAPE_NORMAL;
                        }
                    } else if (orientation < 315 && orientation >= 225) {
                        if (mOrientation != ORIENTATION_PORTRAIT_INVERTED) {
                            mOrientation = ORIENTATION_PORTRAIT_INVERTED;
                        }                       
                    } else if (orientation < 225 && orientation >= 135) {
                        if (mOrientation != ORIENTATION_LANDSCAPE_INVERTED) {
                            mOrientation = ORIENTATION_LANDSCAPE_INVERTED;
                        }                       
                    } else if (orientation <135 && orientation > 45) { 
                        if (mOrientation != ORIENTATION_PORTRAIT_NORMAL) {
                            mOrientation = ORIENTATION_PORTRAIT_NORMAL;
                        }                       
                    }                       
                } else {  // portrait oriented devices

                    if (orientation >= 315 || orientation < 45) {
                        if (mOrientation != ORIENTATION_PORTRAIT_NORMAL) {                          
                            mOrientation = ORIENTATION_PORTRAIT_NORMAL;
                        }
                    } else if (orientation < 315 && orientation >= 225) {
                        if (mOrientation != ORIENTATION_LANDSCAPE_NORMAL) {
                            mOrientation = ORIENTATION_LANDSCAPE_NORMAL;
                        }                       
                    } else if (orientation < 225 && orientation >= 135) {
                        if (mOrientation != ORIENTATION_PORTRAIT_INVERTED) {
                            mOrientation = ORIENTATION_PORTRAIT_INVERTED;
                        }                       
                    } else if (orientation <135 && orientation > 45) { 
                        if (mOrientation != ORIENTATION_LANDSCAPE_INVERTED) {
                            mOrientation = ORIENTATION_LANDSCAPE_INVERTED;
                        }                       
                    }
                }


            }
        };
    }
    if (mOrientationEventListener.canDetectOrientation()) {
        mOrientationEventListener.enable();
    }

不要忘记调用OrientationEventListener.disable（）;

修改

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

如何相对于设备的主体获得活动的真实轮换

1 个答案: