How to detect my screen orientation in portrait locked screen in android?

You can use OrientationEventListener for this. this is class that customise it.

public abstract class SimpleOrientationListener extends OrientationEventListener {

        public static final int CONFIGURATION_ORIENTATION_UNDEFINED = Configuration.ORIENTATION_UNDEFINED;
        private volatile int defaultScreenOrientation = CONFIGURATION_ORIENTATION_UNDEFINED;
        public int prevOrientation = OrientationEventListener.ORIENTATION_UNKNOWN;
        private Context ctx;
        private ReentrantLock lock = new ReentrantLock(true);

        public SimpleOrientationListener(Context context) {
            super(context);
            ctx = context;
        }

        public SimpleOrientationListener(Context context, int rate) {
            super(context, rate);
            ctx = context;
        }

        @Override
        public void onOrientationChanged(final int orientation) {
            int currentOrientation = OrientationEventListener.ORIENTATION_UNKNOWN;
            if (orientation >= 330 || orientation < 30) {
                currentOrientation = Surface.ROTATION_0;
            } else if (orientation >= 60 && orientation < 120) {
                currentOrientation = Surface.ROTATION_90;
            } else if (orientation >= 150 && orientation < 210) {
                currentOrientation = Surface.ROTATION_180;
            } else if (orientation >= 240 && orientation < 300) {
                currentOrientation = Surface.ROTATION_270;
            }

            if (prevOrientation != currentOrientation && orientation != OrientationEventListener.ORIENTATION_UNKNOWN) {
                prevOrientation = currentOrientation;
                if (currentOrientation != OrientationEventListener.ORIENTATION_UNKNOWN)
                    reportOrientationChanged(currentOrientation);
            }

        }

        private void reportOrientationChanged(final int currentOrientation) {

            int defaultOrientation = getDeviceDefaultOrientation();
            int orthogonalOrientation = defaultOrientation == Configuration.ORIENTATION_LANDSCAPE ? Configuration.ORIENTATION_PORTRAIT
                    : Configuration.ORIENTATION_LANDSCAPE;

            int toReportOrientation;

            if (currentOrientation == Surface.ROTATION_0 || currentOrientation == Surface.ROTATION_180)
                toReportOrientation = defaultOrientation;
            else
                toReportOrientation = orthogonalOrientation;

            onSimpleOrientationChanged(toReportOrientation);
        }

        /**
         * Must determine what is default device orientation (some tablets can have default landscape). Must be initialized when device orientation is defined.
         *
         * @return value of {@link Configuration#ORIENTATION_LANDSCAPE} or {@link Configuration#ORIENTATION_PORTRAIT}
         */
        private int getDeviceDefaultOrientation() {
            if (defaultScreenOrientation == CONFIGURATION_ORIENTATION_UNDEFINED) {
                lock.lock();
                defaultScreenOrientation = initDeviceDefaultOrientation(ctx);
                lock.unlock();
            }
            return defaultScreenOrientation;
        }

        /**
         * Provides device default orientation
         *
         * @return value of {@link Configuration#ORIENTATION_LANDSCAPE} or {@link Configuration#ORIENTATION_PORTRAIT}
         */
        private int initDeviceDefaultOrientation(Context context) {

            WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
            Configuration config = context.getResources().getConfiguration();
            int rotation = windowManager.getDefaultDisplay().getRotation();

            boolean isLand = config.orientation == Configuration.ORIENTATION_LANDSCAPE;
            boolean isDefaultAxis = rotation == Surface.ROTATION_0 || rotation == Surface.ROTATION_180;

            int result = CONFIGURATION_ORIENTATION_UNDEFINED;
            if ((isDefaultAxis && isLand) || (!isDefaultAxis && !isLand)) {
                result = Configuration.ORIENTATION_LANDSCAPE;
            } else {
                result = Configuration.ORIENTATION_PORTRAIT;
            }
            return result;
        }

        /**
         * Fires when orientation changes from landscape to portrait and vice versa.
         *
         * @param orientation value of {@link Configuration#ORIENTATION_LANDSCAPE} or {@link Configuration#ORIENTATION_PORTRAIT}
         */
        public abstract void onSimpleOrientationChanged(int orientation);

    }

Then where you want to detect orientation just call

SimpleOrientationListener mOrientationListener = new SimpleOrientationListener(
                context) {

            @Override
            public void onSimpleOrientationChanged(int orientation) {
                if(orientation == Configuration.ORIENTATION_LANDSCAPE){

                }else if(orientation == Configuration.ORIENTATION_PORTRAIT){

                }
            }
        };
        mOrientationListener.enable();