提高uitableview的性能

Question

I have this application that I am letting the user set up a search query based of values selected by them from a bunch of xml data that will then be used to search the database for stuff.

At the moment I have 3 cells that can accept search parameters for the query, each cell loads its data onto the same uitableview so I have to do abit of fudging with my if statements to make sure everything works correctly for the correct dataset.

the first cell allows the user to pick a motorbike manufacture, all of the manufactures are listed on the table view. the xml that is being loaded has a key value that is related to the second list which lists the model of every manfacture. I am wanting to set up the list of manufactures based of the manufacture selection as soon as the user selectes a tableviewcell.

so that when the user is back to the main view then selects the second cell the (dictionary) that i have created loads really fast.

At the moment everything is done each time the subview is loaded.. so because my manufacture list is so big, when the user selects the manufacture they would like to search when the come back to the subview with the manufactre selected the id has to be compaired to every single model of every single manufacture to get the list to display which takes a very long time.

I would like to know how you would attempt something like this. below is a flow chart of how I am thinking to do it. I would like some comments/suggestions on if you think im doing it right or not and also how to even attempt this.

any help would be greatly appreciated (if you cannot read the text in the image you can right click save to desktop and its alot bigger)

Answer 1

To do this properly you probably want to use some sort of data structure in your application which allows fast querying rather than doing multiple parses of your xml input file.

For a simple "first-cut" solution you could parse the XML file into an NSDictionary and query this for Manufacturer -> Model relationships. You can build the NSDictionary once off the XML file then persist the result somewhere and searching will be much faster than looking through the XML each time.

For something more robust it'd be worth looking into using CoreData to store your Manufacturer -> Model relationship. This would take more code on your behalf but would give you a much nicer object model.