我一直在处理一段代码来预览和捕获片段中的照片。我是通过在相机上关注Airpair指南来做到这一点的。
问题是：Android相机预览旋转了90度，因此在某些设备中看起来也很紧张。
注意：我在我的三星Galaxy Alpha（4.9英寸屏幕）上试过这个并且它运行正常。然而，在华为P8（5英寸屏幕）和nexus 5x（5.2英寸屏幕）中，它显示了90度旋转拉伸预览。
我见过其他人在'SO'上发布了类似的问题，但是这些解决方案已经集成到了这个代码中。
例如覆盖protected void onLayout(boolean changed, int left, int top, int right, int bottom)用于修复旋转。
如果你能指出我一直缺少的东西，我将不胜感激。
/**
* A simple {@link Fragment} subclass.
*/
public class KycCameraFragment extends Fragment {
public static final String TAG = "KycCameraFragment";
// Native camera.
private Camera mCamera;
// View to display the camera output.
private CameraPreview mPreview;
// Reference to the containing view.
private View mCameraView;
public KycCameraFragment() {
// Required empty public constructor
}
@Override
public void onStart() {
super.onStart();
// register the event to listen.
GlobalBus.getBus().register(this);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_kyc_camera, container, false);
// Create our Preview view and set it as the content of our activity.
boolean opened = safeCameraOpenInView(view);
if(opened == false){
Log.d("CameraGuide","Error, Camera failed to open");
return view;
}
// Trap the capture button.
Button captureButton = (Button) view.findViewById(R.id.button_capture);
captureButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
// get an image from the camera
mCamera.takePicture(null, null, mPicture);
}
}
);
return view;
}
@Subscribe(sticky = true)
public void getMessage(Events.FragmentIdTypeMessage fragmentIdTypeMessage) {
TextView _tvEKYCCamera = (TextView) getView().findViewById(R.id.tvEKYCCamera);
_tvEKYCCamera.setText("Message from Fragment ID type" + " " + fragmentIdTypeMessage.getMessage());
Toast.makeText(getContext(),
"Message Received: " + fragmentIdTypeMessage.getMessage(),
Toast.LENGTH_SHORT).show();
}
@Override
public void onDestroyView() {
super.onDestroyView();
// unregister the registered event.
releaseCameraAndPreview();
GlobalBus.getBus().unregister(this);
}
/**
* Recommended "safe" way to open the camera.
* @param view
* @return
*/
private boolean safeCameraOpenInView(View view) {
boolean qOpened = false;
releaseCameraAndPreview();
mCamera = getCameraInstance();
mCameraView = view;
qOpened = (mCamera != null);
if(qOpened == true){
mPreview = new CameraPreview(getActivity().getBaseContext(), mCamera,view);
FrameLayout preview = (FrameLayout) view.findViewById(R.id.camera_preview);
preview.addView(mPreview);
mPreview.startCameraPreview();
}
return qOpened;
}
/**
* Safe method for getting a camera instance.
* @return
*/
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
e.printStackTrace();
}
return c; // returns null if camera is unavailable
}
/**
* Clear any existing preview / camera.
*/
private void releaseCameraAndPreview() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
if(mPreview != null){
mPreview.destroyDrawingCache();
mPreview.mCamera = null;
}
}
/**
* Surface on which the camera projects it's capture results. This is derived both from Google's docs and the
* excellent StackOverflow answer provided below.
*
* Reference / Credit: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
*/
class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
// SurfaceHolder
private SurfaceHolder mHolder;
// Our Camera.
private Camera mCamera;
// Parent Context.
private Context mContext;
// Camera Sizing (For rotation, orientation changes)
private Camera.Size mPreviewSize;
// List of supported preview sizes
private List<Camera.Size> mSupportedPreviewSizes;
// Flash modes supported by this camera
private List<String> mSupportedFlashModes;
// View holding this camera.
private View mCameraView;
public CameraPreview(Context context, Camera camera, View cameraView) {
super(context);
// Capture the context
mCameraView = cameraView;
mContext = context;
setCamera(camera);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setKeepScreenOn(true);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
/**
* Begin the preview of the camera input.
*/
public void startCameraPreview()
{
try{
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
}
catch(Exception e){
e.printStackTrace();
}
}
/**
* Extract supported preview and flash modes from the camera.
* @param camera
*/
private void setCamera(Camera camera)
{
// Source: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
mCamera = camera;
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
mSupportedFlashModes = mCamera.getParameters().getSupportedFlashModes();
// Set the camera to Auto Flash mode.
if (mSupportedFlashModes != null && mSupportedFlashModes.contains(Camera.Parameters.FLASH_MODE_AUTO)){
Camera.Parameters parameters = mCamera.getParameters();
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);
mCamera.setParameters(parameters);
}
requestLayout();
}
/**
* The Surface has been created, now tell the camera where to draw the preview.
* @param holder
*/
public void surfaceCreated(SurfaceHolder holder) {
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Dispose of the camera preview.
* @param holder
*/
public void surfaceDestroyed(SurfaceHolder holder) {
if (mCamera != null){
mCamera.stopPreview();
}
}
/**
* React to surface changed events
* @param holder
* @param format
* @param w
* @param h
*/
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
Camera.Parameters parameters = mCamera.getParameters();
// Set the auto-focus mode to "continuous"
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
// Preview size must exist.
if(mPreviewSize != null) {
Camera.Size previewSize = mPreviewSize;
parameters.setPreviewSize(previewSize.width, previewSize.height);
}
mCamera.setParameters(parameters);
mCamera.startPreview();
} catch (Exception e){
e.printStackTrace();
}
}
/**
* Calculate the measurements of the layout
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// Source: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null){
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
/**
* Update the layout based on rotation and orientation changes.
* @param changed
* @param left
* @param top
* @param right
* @param bottom
*/
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom)
{
// Source: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
if (changed) {
final int width = right - left;
final int height = bottom - top;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null){
Display display = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
switch (display.getRotation())
{
case Surface.ROTATION_0:
previewWidth = mPreviewSize.height;
previewHeight = mPreviewSize.width;
mCamera.setDisplayOrientation(90);
break;
case Surface.ROTATION_90:
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
break;
case Surface.ROTATION_180:
previewWidth = mPreviewSize.height;
previewHeight = mPreviewSize.width;
break;
case Surface.ROTATION_270:
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
mCamera.setDisplayOrientation(180);
break;
}
}
final int scaledChildHeight = previewHeight * width / previewWidth;
mCameraView.layout(0, height - scaledChildHeight, width, height);
}
}
/**
*
* @param sizes
* @param width
* @param height
* @return
*/
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int width, int height)
{
// Source: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
Camera.Size optimalSize = null;
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) height / width;
// Try to find a size match which suits the whole screen minus the menu on the left.
for (Camera.Size size : sizes){
if (size.height != width) continue;
double ratio = (double) size.width / size.height;
if (ratio <= targetRatio + ASPECT_TOLERANCE && ratio >= targetRatio - ASPECT_TOLERANCE){
optimalSize = size;
}
}
// If we cannot find the one that matches the aspect ratio, ignore the requirement.
if (optimalSize == null) {
// TODO : Backup in case we don't get a size.
}
return optimalSize;
}
}
/**
* Picture Callback for handling a picture capture and saving it out to a file.
*/
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null){
Toast.makeText(getActivity(), "Image retrieval failed.", Toast.LENGTH_SHORT)
.show();
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
// Restart the camera preview.
safeCameraOpenInView(mCameraView);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
};
/**
* Used to return the camera File output.
* @return
*/
private File getOutputMediaFile(){
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MM");
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("CameraGuide", "Required media storage does not exist");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
Toast.makeText(getActivity(),"Your picture has been saved!", Toast.LENGTH_LONG).show();
// DialogHelper.showDialog( "Success!","Your picture has been saved!",getActivity());
return mediaFile;
}
}
片段布局：
RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary"
>
<!-- TODO: Update blank fragment layout -->
<TextView
android:id="@+id/tvEKYCCamera"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="@string/hello_blank_fragment" />
<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerInParent="true"
android:orientation="vertical"
android:gravity="center"
>
<View
android:id="@+id/myRectangleView"
android:layout_width="300dp"
android:layout_height="300dp"
android:background="@drawable/rectangle"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Place ID Within Here"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_alignParentBottom="true"
android:orientation="horizontal"
android:gravity="center">
<Button
android:id="@+id/button_capture"
android:text=""
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_margin="10dp"
android:background="@drawable/camera_button"
/>
</LinearLayout>
答案 0 :(得分：0)
经过一些实验，我发现通过设置case Surface.ROTATION_90:而覆盖protected void onLayout(boolean changed, int left, int top, int right, int bottom)解决了方向问题。
显然有些相机的默认方向是0度，大约是90度。
以下是我可能面临同样问题的人所做的改变：
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom)
{
// Source: http://stackoverflow.com/questions/7942378/android-camera-will-not-work-startpreview-fails
if (changed) {
final int width = right - left;
final int height = bottom - top;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null){
Display display = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
switch (display.getRotation())
{
case Surface.ROTATION_0:
previewWidth = mPreviewSize.height;
previewHeight = mPreviewSize.width;
mCamera.setDisplayOrientation(90);
break;
case Surface.ROTATION_90:
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
//added to fix rotation issue
mCamera.setDisplayOrientation(90);
break;
case Surface.ROTATION_180:
previewWidth = mPreviewSize.height;
previewHeight = mPreviewSize.width;
//added to fix rotation issue
mCamera.setDisplayOrientation(180);
break;
case Surface.ROTATION_270:
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
mCamera.setDisplayOrientation(180);
break;
}
}
final int scaledChildHeight = previewHeight * width / previewWidth;
mCameraView.layout(0, height - scaledChildHeight, width, height);
}
}