package com.michaldabski.utils;

import android.util.SparseArray;
import android.view.View;

public class ViewHolder
{
	final View root;
	final SparseArray<View> views = new SparseArray<View>(3);
	
	public ViewHolder(View root)
	{
		this.root = root;
	}
	
	@SuppressWarnings("unchecked")
	public <T extends View> T getViewById(int id)
	{
		T view = (T) views.get(id);
		if (view == null)
		{
			views.put(id, (view = (T) root.findViewById(id)));
			if (view == null)
				throw new NullPointerException("Cannot find requested view id "+String.valueOf(id));
		}
		return view;
	}
}

package com.michaldabski.utils;

import android.util.SparseArray;
import android.view.View;

public class ViewHolder
{
	final View root;
	final SparseArray<View> views = new SparseArray<View>(3);
	
	public ViewHolder(View root)
	{
		this.root = root;
	}
	
	@SuppressWarnings("unchecked")
	public <T extends View> T getViewById(int id)
	{
		T view = (T) views.get(id);
		if (view == null)
		{
			views.put(id, (view = (T) root.findViewById(id)));
			if (view == null)
				throw new NullPointerException("Cannot find requested view id "+String.valueOf(id));
		}
		return view;
	}
	
	public boolean hasView(int id)
	{
		if (views.get(id) != null) return true;
		else
		{
			View view = this.root.findViewById(id);
			if (view == null) return false;
			else
			{
				views.put(id, view);
				return true;
			}
		}
	}
}

Add hasView() method to viewHolder