Database Reference
In-Depth Information
Less More
Memory
Slow Fast
Speed
iOS
OS X
On iOS devices in particular, there is less available RAM and as a result, you can't
load as much data. With fewer model objects in RAM, your app's operations will be
slower due to frequent slow disk access. If you use too much RAM, your app will
receive low memory warnings and the system may even terminate your app!
The more model objects you load into RAM, the faster your app will be, but then
your app will be using more RAM. You can minimize RAM usage, but then your app
will be slower because more of your model objects are on disk.
The starter project
The starter project,
Employee Directory
, is a tab-bar based app full of employee
information. It's like the Contacts app, but for a single fictional company.
Open the starter project for this chapter in the
EmployeeDirectory-Starter
folder
and build and run it in Xcode.
The app will take a long time to launch and once it does launch, it will feel sluggish
and may even crash as you use it. Rest assured, this is by design!
Note:
It's possible the starter project may not even launch on your system. I
made the app to be as sluggish as possible while still able to run on most
systems, so that the performance improvements you'll make will be easily
noticeable.
If the app refuses to work on your system, continue to follow along. The first
set of changes you make should enable the app to work on even the slowest
devices.
As you can see in the following screenshots, the first tab includes a table view and
a custom cell with basic information, such as name and department, for all
employees. Tapping on a cell reveals more details for the selected employee, such
as start date and remaining vacation days.
