In my app I see terrible performance when I add some custom components to a UIImageView. It’s most likely the aforementioned custom components and they will need to be improved upon, but I’d like to be able to measure said improvements down the road. I’d also like to see how many times the UIImageView is drawn during the animation of a particular view.
One strategy that I’ve kicked around is subclassing UIImageView (only for the purpose of benchmarking) and having overridden ‘draw’ methods in my subclass log something and then call the super class’s method.
This would be fine, save for drawRect won’t be called for subclasses of UIImageView. Are there ‘drawing’ methods for UIImageView that I could override in this manner?
In theory, I could accomplish something similar by substituting a subclass of UIImageView with a subclass of UIView, but this will become a bit more invasive and I’d only like to do this as a last resort.
Finally, am I down a rabbit trail and there’s a really obvious solution (or tool) staring me in the face? I know Instruments can provide some profiling in terms of frame rates in this area, but I don’t see a solution to my problem with my limited knowledge of the tool.
Use Instruments.
It’s made for these things. You even said it yourself.
The "Instruments User Guide" is a good place to start if you’ve never used it before.
Learning how to use instruments is time well spent. You will always have use for it when performance tuning your app, looking for memory leaks, etc.
If you really are determined to know the execution time of a method then you could have a look at DTrace. It’s very powerful but a much harder than Instruments. You can also use it to build your custom tools in Instruments.