我已经查看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
提供尺寸的功能如下所示......
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，当我更改设备的方向时，预览图片会保持风景。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才能正确旋转？
答案 0 :(得分：32)
正确调整相机预览方向的代码有点复杂，因为必须考虑
Camera.setDisplayOrientation的文档包含有关如何正确处理此问题的示例代码。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后调用此方法（onSurfaceChanged可用作指示符）或设备UI旋转（onConfigurationChanged将用作指示符）。
答案 1 :(得分：8)
我能够通过将以下代码放在onSurfaceChanged（）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());
}
但是这会产生另一个问题，或者说更好的问题，并没有解决问题 - 虽然正确定位，预览图像仍然只占用了景观视图所用的相同空间。我最终只是放弃并强迫横向进行：
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
并设计了我的横向布局。祝你好运，我希望有人能解决这个次要问题！
答案 2 :(得分：6)
尝试这一点，但我尝试使用三星Galaxy Tab
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;
}
}
答案 3 :(得分：2)
我通过添加：
解决了这个问题setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
到onCreate事件。
答案 4 :(得分：2)
请试试这个..
@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();
}
}
答案 5 :(得分：2)
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;
}
}
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);
}
3：确保您在此活动之前添加了摄像头permiison以支持活动中的牛轧糖，因为此活动中没有呼叫摄像机的权限，因为已创建活动的表面创建呼叫，并且您的权限将等待打开摄像头
答案 6 :(得分：-1)
仅添加
mCamera.setDisplayOrientation(90);