-(void)showLoadingView
{
	CGRect transparentViewFrame = CGRectMake(0.0, 0.0,320.0,480.0);
	transparentView = [[UIView alloc] initWithFrame:transparentViewFrame];
	transparentView.backgroundColor = [UIColor lightGrayColor];
	transparentView.alpha = 0.9;

	UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
	spinner.center = transparentView.center;
	[spinner startAnimating];

	UILabel *messageLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 280, 320, 30)];
	messageLabel.textAlignment = UITextAlignmentCenter;
	messageLabel.text = @"please wait...";

	[transparentView addSubview:spinner];
	[transparentView addSubview:messageLabel];

	[self.view addSubview:transparentView];

	[messageLabel release];
	[spinner release];
	[transparentView release];
}

Now, you should call this function whenever needed. Let’s say you have a background process that will run while the transparent loading view is shown, below is the code to handle this situation:

-(void)myAction:(id)sender
{
	[self showLoadingView];

	[self performSelectorInBackground:@selector(myActionBackground:) withObject:sender];
}

-(void)myActionBackground:(id)sender
{
        NSAutoreleasePool *apool = [[NSAutoreleasePool alloc] init];
	//your code
        [apool release];
}

Memcache provides convenience to store a frequent query in memory, so that you don’t have to make the same execution over and over again. For the iPhone application I build (Fragman), I build a GAE/J backend for managing movie names, IMDB URLs, thumb images, video files, etc. It interacts with the Obj-c code via calls encoded in JSON.

Since the categories are updated so frequently (new trailer, top 250 , soap opera trailers), every time the user starts the application from her iPhone, the corresponding categories Id(key) lists are  created which includes all the aspects mentioned above,

what I see, after people start to use the application that, most of the time, the application got stuck with the time constraint of GAE and this causes inconvenience, so I decided to hold the category lists’s JSON in memory. Following is the code ,

this is the servlet for creating the JSON which is called after say upcoming movie list is changed. This servlet updates the memcached list

        List keyList = new ArrayList();
	static Cache cache;
	static
	{
		try
		{
			CacheFactory cacheFactory =

CacheManager.getInstance().getCacheFactory();
			cache = cacheFactory.createCache(

Collections.emptyMap());
		}
		catch (CacheException e)
		{
			// ...
		}
		//.....
                public void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException

	        {
                       //................
                       if(cache.containsKey(mode))
		       {
			     cache.remove(mode);
		       }
		       cache.put(mode, keyList);
	        }

                //........

          }

And this is the servlet that fetch the Fragman beans from the datastore with the given keys (key list is got from the memecached list)

          keyList = (List)cache.get(mode);

By doing this, I reduce the time that the servlet that creates the JSON takes.