构建应用以在单个UITableView中显示两个列表的最佳方法是什么（在数据集之间切换）

Question

I'm relatively new to iOS development and am just wanting a few pointers as to what will be the best way to go about doing this. I am building an app with a tab bar and one of those tabs will be a table view at the top of which is a segmented control with two buttons allowing you to swap between datasets.

The first question I have is:

The data is relatively simple but there are about 6000 records would it be best to use a simple NSDictionary as the data source or should I look into using Core Data. Users of the app will simply be able to select a record to add it to a favourites list, or deselect it.

Secondly:

Should I use two different view controllers and swap them in and out depending on which option is selected or should I use a single view controller and swap the data in that class to populate the table.

I'm a registered Apple Dev so I have access to their examples but often can find them difficult to follow, any pointers to resources/tutorials would be VERY appreciated.

Answer 1

First off, for anything nontrivial always consider Core Data - in your case especially so. A 6000-object dictionary can easily get unwieldy to manage.

As for the view controllers, I believe the canonical thing to do is to use a single table view controller (since you remain on a single UITabBarController tab), but change out its data source, or just change the data returned from that source.

If you need it to look reasonably smooth, you can play with the built-in UITableView animation methods - I believe the AP application changed out its news stories by animating out all the old ones and animating in all the new ones within a single table view, so the effect was of a complete dataset change but without the extra view controller.

Generally I've found the Apple examples and tutorials to be the best available, but there's no substitute for just building apps and playing around with the technologies yourself - if you don't understand an example, try to reimplement it yourself and see what's giving you trouble. If you're truly stuck on something, come back and ask another question!

Answer 2

First question:

If your dataset is fairly simple, I would recommend sticking with an array of dictionaries; or, if order is well-defined, and each row has a meaningful unique key, simply use a dictionary.

There's a complexity tradeoff involved in using a large framework like Core Data, and until you have—for instance—relationships expressed in your object model, I don't think the tradeoff is worth taking.

That said, there are performance issues to take into account when making these kinds of decisions. You have 6,000 records, but is each just a key and a value? That wouldn't be such a big deal. But if you have a number of columns, and sorting is an issue, Core Data's SQLite backend would help you out a great deal.

If the array or dictionary is filled with standard Foundation data types, you'd get serialization for free, since all of them implement NSCoding.

Second question:

Read through Apple's article on the model-view-controller design paradigm . The thing to note about what you're trying to do here is that since you're only looking to vary your data, only your model should be changing.

UITableView is designed to make that easy. It's a view, so it doesn't store its data, but it has a dataSource property which it queries to display information. So when your user switches datasets, simply switch your table view's data source.