Android :: Find GPS Location Once / Show Loading Dialog

I am writing an app that requires the user's current location (lastknownlocation won't be very helpful) and displays a list of all the closest "items" to them taken from the database.I have got the finding of the closest items working well but only using a hardcoded latitude and longitude location for the time being but now it is time to implement finding the actual location.Can anyone provide an example of how to have the app find the current fine location in the background and have the app wait. I only need the location once not updates as the person moves. I have implemented a location listener however I understand getting a GPS fix can be slow. I have seen other examples using last known location or implementing the location listener which continues to run and update however as my Activity needs the location coordinates before it can display anything the app just crashes. I need to show a Progress Dialog while its searching.

How can I have the locationlistener run once in the background and then remove location updates once it finds the location. I need the rest of the application to wait until it has a GPS location or timeout after say 20-30seconds. I would like a ProgressDialog up so the user knows that something is going on, but it just has to be the spinning loading animation not a percentage or anything. If possible I would like the user to be able to cancel the dialog if they are sick of waiting which then they can search by typing suburb etc instead.I have been trying to do it with threads but it is getting way more complicated than I feel it should be and still not working anyway. On iPhone this is much more simple?Can anyone provide a nice way of doing this, I have been ripping my hair out for a week on this and it is really putting me behind schedule for the rest of the app completion date.