I am creating an app with a WebView and a menu on top of the page. I made that menu is invisible and would only appear when a button is clicked. That worked fine but that button couldn't fit anywhere nicely so instead of clicking a button I made it so that the menu would appear when you double tap on the screen. 
So here's the problem. Double tap only works on empty space, but not on WebView. How would I make it work, so it would appear/disappear whenever I double tap the screen?

```
public class MainActivity extends Activity implements OnGestureListener{

private WebView webView;
LinearLayout toolbar;
private GestureDetector gd;

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
    WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.activity_main);

    webView =((WebView)findViewById(R.id.webView1));
    webView.setWebViewClient(new WebViewClient());
    WebSettings webSettings = webView.getSettings();
    webSettings.setJavaScriptEnabled(true);

    webView.setVerticalScrollBarEnabled(true);

    webView.loadUrl("URL_HERE");

    gd = new GestureDetector(this);

    gd.setOnDoubleTapListener(new OnDoubleTapListener()  
    {  
        @Override  
        public boolean onDoubleTap(MotionEvent e)  
        {  
            LinearLayout toolbar= (LinearLayout)findViewById(R.id.toolbar);

            if(toolbar.getVisibility() == View.GONE){
                toolbar.setVisibility(View.VISIBLE);

            }
            else {
                toolbar.setVisibility(View.GONE);

            }
            return false;  
        }  

        @Override  
        public boolean onDoubleTapEvent(MotionEvent e)  
        {  
            return false;  
        }  

        @Override  
        public boolean onSingleTapConfirmed(MotionEvent e)  
        {  
            return false;  
        }  
    });  

}

@Override  
public boolean onTouchEvent(MotionEvent event)  
{  
    return gd.onTouchEvent(event);//return the double tap events  
}  

@Override  
public boolean onDown(MotionEvent e)  
{  
    return false;  
}  

@Override  
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)  
{  
    return false;  
}  

@Override  
public void onLongPress(MotionEvent e)  
{  
}  

@Override  
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)  
{  
    return false;  
}  

@Override  
public void onShowPress(MotionEvent e)  
{  
}  

@Override  
public boolean onSingleTapUp(MotionEvent e)  
{  
    return false;  
}  

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}
}

```

Any help will be appreciated.