Spent most of the week on a new client iPhone app. Quite an interest project for a fairly big client, hopefully it should result in a large number of downloads when I get it finished. The first thing I needed to do was to interface with their OAuth API. This was as fiddly as ever, not helped by the fact that their API returned XML during the OAuth handshaking when every (well, both) OAuth API I’ve worked with in the past has returned URL encoded key/value pairs. Got past that though and managed to get the OAuth stuff working well. I then integrated the code that I worked on recently for showing data in a hierarchical format. That worked pretty well, I’m really stretching the limits of what that code can do now but considering that code was based on the iPhone’s iPod application and the app I’m building is related to music playing it should work out quite well.

In essence the app needs to do the following:

  1. Authenticate with the client’s API
  2. Download user information
  3. Present that information to the user
  4. Allow the user to select items to download from the server
  5. Download the selected items
  6. Allow the user to interact with the downloaded items

I’m now 4 days into the project (took Friday off) and I believe I’ve completed the first 4 of those tasks with just the last two to go. I’m hoping the downloading will be simple enough as I’ve covered something very similar in the chess app just a few weeks ago, and then hopefully the interacting won’t take too long either. I’m really trying to get the bulk of the work on this one finished early so there’s more time to spend testing and fixing bugs later. As you’ve probably noticed I’ve found recently that the iPhone apps have been taking longer than I’ve been predicting!

Friday was spent working on my existing client’s slightly buggy iPhone app. It was being reported that the current version of the app with my changes was running slower than the last version before I got involved. Obviously this reflects badly on me so I was eager to find out what I was doing wrong. The problem basically came down to a point where the original developer had allowed an in-memory dataset to become invalid. It didn’t matter in that version of the app though because no-one would be able to see that it was invalid, whereas my version allowed some editing. This meant that when I added a new item to the dataset that overlapped on an existing one I was downloading all the data from the server again. This meant two network connections per-action and so was making the action doubly slow, especially noticeable over a 3G or GPRS connection. Fortunately I was able to handle the overlapping on the device so that only in very specific cases do I need to request all the data again (basically when one item gets broken into two items, they will both get new identifiers so I need to call back to the server to find out what the new identifiers are).

This week I’m back on the new client app all week, really hoping to get it finished, possibly even a day or two early to allow maximum time for testing.