Question

我正在尝试在片段中设置相机预览，并在预览上添加一些xml元素，如按钮和符号。但是使用addview时，相机的预览会因设备比例和相机而异。有时它会在顶部，有时它会在底部将捕捉按钮推出布局。

注意：我一直在尝试将包含预览的{"not_auth":"Invalid credentials. Please try again"}设置为framelayout或centercrop。然而，在以编程方式添加预览usign alignparenttop之后，它会在某些设备中将元素从布局视图中推出时继续显示未对齐。同时在某些设备中，它会显示与顶部对齐的布局以及位于framlayout上方的元素。

这是我的片段代码

addView

我的片段XML：

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_round.
    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);
                        Log.d(TAG,"0 degree camera orientation got hit");
                        break;
                    case Surface.ROTATION_90:
                        previewWidth = mPreviewSize.width;
                        previewHeight = mPreviewSize.height;
                        //added to fix rotation issue
                        Log.d(TAG,"90 degree camera orientation got hit");

                        break;
                    case Surface.ROTATION_180:
                        previewWidth = mPreviewSize.height;
                        previewHeight = mPreviewSize.width;
                        //added to fix rotation issue
                        mCamera.setDisplayOrientation(0);
                        Log.d(TAG,"180 degree camera orientation got hit");
                        break;
                    case Surface.ROTATION_270:
                        previewWidth = mPreviewSize.width;
                        previewHeight = mPreviewSize.height;
                        mCamera.setDisplayOrientation(180);
                        Log.d(TAG,"270 degree camera orientation got hit");
                        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)
    {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) height / width;

        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = height;

        for (Camera.Size size : sizes) {
            double ratio = (double) size.height / size.width;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;

            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }

        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;
}
}

以编码方式将片段xml中的相机预览添加到帧布局中

0 个答案: