Instruments - iOS Programming: The Big Nerd Ranch Guide - page 604

the Run button in the Xcode workspace with the exception of Archive .) Selecting a
scheme action here shows its options in the details pane. Take a moment to look over the
actions and the available options. Notice that some actions have multiple tabs that cat-
egorize their options.
Creating a new scheme
As projects become larger and more complicated, they require more specific testing and
debugging. To avoid having to constantly edit one scheme, we typically create new
schemes for common situations. For example, if we have an application that consumes a
lot of memory, we might want to routinely run the Allocations instrument on it. Instead of
having Instruments ask which instrument to use when we profile the application, we can
set up a new scheme that always runs Allocations .
Let's set up this scheme for the TouchTracker target. From the Scheme pop-up menu, se-
lect New Scheme... . When the sheet drops down, enter Allocations into the name and
make sure TouchTracker is selected as the target ( Figure 21.22 ). Click OK .
Figure 21.22 Creating a new scheme
Reopen the scheme editor sheet either by selecting Edit Scheme... from the Scheme pop-
up menu or using the keyboard shortcut Command-Shift-<. Then click the Scheme pop-up
menu in the scheme editor and select Allocations . Select the Profile action from the left
table. On the detail pane, change the Instrument pop-up to Allocations and click OK ( Fig-
ure 21.23 ) .
Figure 21.23 An allocations-only scheme