Viewport issue on iOS

viewport-issue-ios.java

package test.run;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.HeadElement;
import com.google.gwt.dom.client.MetaElement;
import com.google.gwt.dom.client.NodeList;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.RootPanel;

public class ViewportTestEntryPoint implements EntryPoint
{
	private MetaElement mViewport = null;
	
	private Button mStartButton = null;
	
	@Override
	public void onModuleLoad()
	{
		mStartButton = new Button();
		mStartButton.setText("Click here");
		mStartButton.getElement().getStyle().setFontSize(48, Unit.PX);
		mStartButton.addClickHandler(new ClickHandler()
		{
			@Override
			public void onClick(ClickEvent aEvent)
			{
				mStartButton.setEnabled(false);
				
				Timer theTimer = new Timer()
				{
					@Override
					public void run()
					{
						optimizeHostPage();
					}
				};
				
				theTimer.schedule(1000);
			}
		});
		
		RootPanel.get().add(mStartButton);
	}

	protected void optimizeHostPage()
	{
		// Disable window scrolling.
		Window.enableScrolling(false);
		
		// Change viewport settings.
		if (mViewport == null) {
			NodeList<Element> theMetaElements = Document.get().getElementsByTagName("meta");
			for (int i = 0; i < theMetaElements.getLength(); i++) {
				Element theElement = theMetaElements.getItem(i);
				if (theElement.getAttribute("name").equalsIgnoreCase("viewport")) {
					mViewport = MetaElement.as(theElement);
					break;
				}
			}
			
			if (mViewport == null) {
				mViewport = Document.get().createMetaElement();
				mViewport.setName("viewport");
			}
		}
		
		mViewport.setContent("width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes");
		
		getHeadElement().appendChild(mViewport);
	}
	
	protected HeadElement getHeadElement()
	{
		Element theElement = Document.get().getElementsByTagName("head").getItem(0);
		assert theElement != null : "HTML Head element required";
		HeadElement theHeadElement = HeadElement.as(theElement);
		return theHeadElement;
	}
}