Halfway Done

Mobile Makers Day 19 — NSNotificationCenter and UIScrollView

Today we learned about NSNotification Center and also UIScrollView (and how much of a pain it is). I am very excited about NSNotification Center since it seems exceptionally powerful. To me it is almost like delegation from different classes to one notification class. I’m not exactly sure when to use it though.

Question: What is a rule of thumb for using NSNotificationCenter versus Delegation?

I’ve built UIScrollViews before and they are still a pain just like they used to be. It takes some fiddling around with, especially when trying to tweek them in the UI, but they are doable.

In our challenge today, we created an app called PeekABoo which is like a photo based contact app. I was concentrating on trying to get the UIImagePicker working so that you are able to take pictures and use them in the app. I don’t think a lot of students went so far as to implement the camera functionality and it still has several quirks that I had previously run into. I am still very confused as to why these quirks are still there. Here are a few that I ran into:

When taking an photo on your phone, it stores the image sideways and you have to rotate it’s corresponding UIImageView 90 degrees clockwise. Why?

Another think that I surprisedly ran into again was scroll stutter on a collection view. I am surprised that, with photos taken from the phone camera and placed into a collection view, the collection view would stutter when dequeued cells were scrolled on and off the screen. I’m not sure if it is the size of the images (I tried to save them as JPEGs with medium to tight compression) or if it is becuase it is translated into NSData and accessed via CoreData. I am really not sure and surprised that it is still there. I will have to research this yet again (practically 2 years and 2 sdk’s later).

Finally, everyone seems to be pumped up about the final projects and ideas are flying around. I was getting a little bit worried about coming up with ideas as other folks seem to be already working on some. I feel that I need to start transitioning into that mode.