Android - Camera preview is sideways

问题:

I am using a Preview to display what the camera see\'s on the screen.

I can get everything working fine, surface created, surface set and the surface is displayed.

However it always displays the picture at an incorrect 90 degree angle in portrait mode.

Such as in the picture:

I am aware that using the following code will set the picture straight:

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

However I have the Preview within an Activity that has other elements in it and it does not make sense for my Activity to be displayed in landscape mode. (Its disabled by default)

So I was wondering is there anyway to just change the orientation of the Preview? And leave the rest of my Activity correctly displayed in Portrait mode?

Or anyway to rotate the preview so that it is displayed correctly?

回答1:

This issue appeared to start out as a bug with certain hardware see here but can be overcome by using the call to mCamera.setDisplayOrientation(degrees) available in API 8. So this is how I implement it:

public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {            
    if (isPreviewRunning) {
        mCamera.stopPreview();
    }

    Parameters parameters = mCamera.getParameters();
    Display display = ((WindowManager)getSystemService(WINDOW_SERVICE)).getDefaultDisplay();

    if(display.getRotation() == Surface.ROTATION_0) {
        parameters.setPreviewSize(height, width);                           
        mCamera.setDisplayOrientation(90);
    }

    if(display.getRotation() == Surface.ROTATION_90) {
        parameters.setPreviewSize(width, height);                           
    }

    if(display.getRotation() == Surface.ROTATION_180) {
        parameters.setPreviewSize(height, width);               
    }

    if(display.getRotation() == Surface.ROTATION_270) {
        parameters.setPreviewSize(width, height);
        mCamera.setDisplayOrientation(180);
    }

    mCamera.setParameters(parameters);
    previewCamera();                      
}

And the previewCamera method :

public void previewCamera() {        
    try {           
        mCamera.setPreviewDisplay(mSurfaceHolder);          
        mCamera.startPreview();
        isPreviewRunning = true;
    } catch(Exception e) {
        Log.d(APP_CLASS, \"Cannot start preview\", e);    
    }
}

This was on an HTC Desire and I had to initially put in logging statements in each of the rotation checks to say what the rotation was and then debugged on the device and watched the logCat output while I rotated the device. For the HTC Desire, 0 was the phone as you would have expected (portrait), 90 degrees was turning the phone 90 degrees COUNTER-CLOCKWISE (I had assumed it would have been clockwise). In the code you\'ll see I didn\'t need to do any display rotation when the phone was at 90 or 180 degrees - the device seemed to handle this itself. Only one point not working properly: The 270 degree rotation is when you turn the device 90 degrees clockwise and the display rotation counters that ok but if you rotate the device 270 degrees counter-clockwise, it doesn\'t appear to compensate it properly.

P.S. Note the swapover of width and height in the appropriate rotations.

回答2:

try to set the display orientation. It solves my problem.

 mCamera.setDisplayOrientation(90);

回答3:

 public void surfaceCreated(SurfaceHolder holder) {
     mCamera = Camera.open();
     mCamera.setDisplayOrientation(90);
     try {
         mCamera.setPreviewDisplay(holder);
         mCamera.setPreviewCallback(new PreviewCallback() {

             @Override
             public void onPreviewFrame(byte[] data, Camera camera) {
             }
         });

     } catch (Exception e) {
         e.printStackTrace();
     }
}

try this code

回答4:

I did it taking advice of mCamera.setDisplayOrientation(90); but also rotated the bitmap because for some reason the others approaches doesnt work for me in version 2.3.3.

For rotate the bitmap i did this:

Matrix matrix = new Matrix();
matrix.postRotate(90);
imageView1 = new ImageView(this);
Bitmap bitmap = BitmapFactory.decodeFile(files[i].getAbsolutePath());
Bitmap rotatedBitmap = Bitmap.createBitmap(bitmap , 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
Bitmap scaledBitmap = Bitmap.createScaledBitmap(rotatedBitmap, 80, 80, true);
imageView1.setImageBitmap(scaledBitmap);

回答5:

I am having problem with front Camera(Upside down issue). Then i use this method

public void setCameraDisplayOrientation(Activity activity , int icameraId , Camera camera1s)
    {
        CameraInfo cameraInfo = new CameraInfo();

        Camera.getCameraInfo(icameraId, cameraInfo);

        int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();

        int degrees = 0; // k

        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 (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT)
        {
            // cameraType=CAMERATYPE.FRONT;

            result = (cameraInfo.orientation + degrees) % 360;
            result = (360 - result) % 360; // compensate the mirror

        }
        else
        { // back-facing

            result = (cameraInfo.orientation - degrees + 360) % 360;

        }
        // displayRotate=result;
        camera.setDisplayOrientation(result);


    }

回答6:

I have compared my code to the tutorial one and what finally fixed it was putting the following code into my AndroidManifext.xml: In the <activity> tag:

android:screenOrientation=\"landscape\"
android:configChanges=\"keyboardHidden|orientation\">

回答7:

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;
    }

    try {
        mCamera.stopPreview();
    } catch (Exception e) {
        e.printStackTrace();
    }

    Camera.Parameters parameters = mCamera.getParameters();
    Display display = ((WindowManager) getContext().getSystemService(WINDOW_SERVICE)).getDefaultDisplay();

    if (display.getRotation() == Surface.ROTATION_0) {
        parameters.setPreviewSize(h, w);
        mCamera.setDisplayOrientation(90);
    }

    if (display.getRotation() == Surface.ROTATION_90) {
        parameters.setPreviewSize(w, h);
        mCamera.setDisplayOrientation(0);
    }

    if (display.getRotation() == Surface.ROTATION_180) {
        parameters.setPreviewSize(h, w);
        mCamera.setDisplayOrientation(270);
    }

    if (display.getRotation() == Surface.ROTATION_270) {
        parameters.setPreviewSize(w, h);
        mCamera.setDisplayOrientation(180);
    }

    previewCamera();
}

public void previewCamera() {
    try {
        mCamera.setPreviewDisplay(mHolder);
        mCamera.startPreview();
    } catch (Exception e) {
        //Log.d(APP_CLASS, \"Cannot start preview\", e);
        e.printStackTrace();
    }
}

回答8:

This piece of line worked for me perfectly

 static {
    ORIENTATIONS.append(Surface.ROTATION_0, 90);
    ORIENTATIONS.append(Surface.ROTATION_90, 180);
    ORIENTATIONS.append(Surface.ROTATION_180, 270);
    ORIENTATIONS.append(Surface.ROTATION_270, 360);
}