18.4. Detecting Shakes on an iOS Device
You want to know when the user shakes an iOS device.
method of your app’s window object.
method of your app’s window will get called whenever a motion has been
captured by iOS. The simplest implementation of this method is
/* Do something with the motion */
as you can see, is of type
UIEventSubtype. One of the values of type
UIEventSubtypeMotionShake, which is what we
are interested in. As soon as we detect this event, we know that the
user has shaken her iOS device. In order to get to our app’s window,
though, we need to subclass
To do so, follow these steps:
In Xcode, while you have your project opened, go to File → New File.
From the lefthand side, make sure iOS is the main category and Cocoa Touch is the subcategory.
In the list on the righthand side, select Objective-C class and then press Next, as shown in Figure 18-3.
Figure 18-3. Creating a new Objective-C class for our window
Now make sure that you are subclassing
UIWindowand then press Next, as shown in Figure 18-4.
Figure 18-4. Subclassing UIWindow
In this screen, set the file name to ...