Android : Not getting orientation by using OrientationEventListener in android

I need to detect an orientation of an device, for that I have written a code below. But I am unable get orientation. Please help.

mOrientationListener = new OrientationEventListener(getApplicationContext()) 
{
    @Override
    public void onOrientationChanged(int orientation) 
    {
        if(orientation == 1)
        {
            setContentView(R.layout.activity_main_portrait);
        }
        else
        {
            setContentView(R.layout.activity_main_landscape);
        }
    }
};