Not getting orientation using OrientationEventListener in android

I need to determine the orientation of the device, for which I wrote the code below. But I cannot get orientation. This is my oncreate () in MainActivity ... If I need to change anything please let me know

protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

    mOrientationListener = new OrientationEventListener(getApplicationContext()) 
    {
        @Override
        public void onOrientationChanged(int orientation) 
        {
            if(orientation == 0)
            {
                setContentView(R.layout.activity_main_portrait);
            }
            else
            {
                setContentView(R.layout.activity_main_landscape);
            }
        }
    };
    if (mOrientationListener.canDetectOrientation()) 
    {          
        mOrientationListener.enable();
    }

    mImgPreview = (ImageView) findViewById(R.id.imgpreview);
    mVideoPreview = (ImageView) findViewById(R.id.videopreview);
    mAudioPreview = (ImageView) findViewById(R.id.audiopreview);

    /*-------Intent to view Image Gallery---------*/
    mImgPreview.setOnClickListener(new OnClickListener() 
    {
        @Override
        public void onClick(View v) 
        {
            Intent intent = new Intent(getApplicationContext(), ImageList.class);
            startActivity(intent);
        }
    });

    /*-------Intent to view Video Gallery---------*/
    mVideoPreview.setOnClickListener(new OnClickListener() 
    {
        @Override
        public void onClick(View v) 
        {
            Intent intent = new Intent(getApplicationContext(), Video.class);
            startActivity(intent);
        }
    });

    /*--------Intent to view Audio Gallery--------*/
    mAudioPreview.setOnClickListener(new OnClickListener() 
    {

        @Override
        public void onClick(View v) 
        {
            Intent intent = new Intent(getApplicationContext(), AudioPlayer.class);
            startActivity(intent);
        }
    });
}

      

        
        
        
      

    

// Thanks in Advance