21.1. Detecting the Availability of an Accelerometer
Problem
In your program, you want to detect whether the accelerometer hardware is available.
Solution
Use the isAccelerometerAvailable
method of CMMotionManager
to detect the accelerometer
hardware. The isAccelerometerActive
method can also be used to detect whether the accelerometer hardware is
currently sending updates to the program.
Let’s first make sure we have imported the required header files:
#import "AppDelegate.h"
#import <CoreMotion/CoreMotion.h>
@implementation
AppDelegate
Next, go on to detect the availability of an accelerometer in the implementation file of our app delegate:
-
(
BOOL
)
application:
(
UIApplication
*
)
application
didFinishLaunchingWithOptions:
(
NSDictionary
*
)
launchOptions
{
CMMotionManager
*
motionManager
=
[[
CMMotionManager
alloc
]
init
];
if
([
motionManager
isAccelerometerAvailable
]){
NSLog
(
@"Accelerometer is available."
);
}
else
{
NSLog
(
@"Accelerometer is not available."
);
}
if
([
motionManager
isAccelerometerActive
]){
NSLog
(
@"Accelerometer is active."
);
}
else
{
NSLog
(
@"Accelerometer is not active."
);
}
self
.
window
=
[[
UIWindow
alloc
]
initWithFrame
:
[[
UIScreen
mainScreen
]
bounds
]];
self
.
window
.
backgroundColor
=
[
UIColor
whiteColor
];
[
self
.
window
makeKeyAndVisible
];
return
YES
;
}
Accelerometer hardware might be available on the iOS device running your program. This, however, does not mean the accelerometer hardware is sending updates to your program. If the accelerometer or gyroscope is sending updates to your ...
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