Graphics Reference
In-Depth Information
NOTE
Nondeletable iPhone/iPod Touch
Applications
When you press and hold your finger on the
application icons on your iPhone/iPod touch,
you notice that certain applications won't
have the little close box in the upper-left
corner. One quick glance tells you that these
are the default applications that ship with
the device (for example, Camera, Clock,
Photos, Settings, Safari, Weather, and so on).
If you have found better third-party applica-
tions for these (well, maybe with the excep-
tion of Settings), you might consider dumping
the unused default applications onto their
own screen.
FIGURE 4-4
The iPhone/iPod Touch
in Edit Mode
This user interface cue helps the user know that the iPhone/iPod touch is now in a differ-
ent state, and you can now make changes to something. It might not be immediately
obvious what that something is; however, once you start tap-dragging, it becomes appar-
ent what you are supposed to do. Cues like this enhance the user experience and make
applications incredibly intuitive. This is one of Core Animation's most useful features, so
let's see how it is done.
Implementing the Icon Shake Using Keyframe Animation
We implement this icon shaking animation with Cocoa on OS X, though the implemen-
tation on the iPhone is similar. We begin by creating the animation and playing it over a
longer duration to show how each parameter of the animation affects what it looks like
when run. Then we set the duration to run at a time that is more on par with what you
actually see on the iPhone/iPod touch.
You might want to open the sample project to see what the effect looks like. We have
provided an example project for both OS X and the iPhone. They are called Icon Dance
for OS X and Icon Dance iPhone for the iPhone.
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