Declaring the Required Device Capabilities

Declaring the Required Device Capabilities

If your application requires device-related features in order to run, you must add a list of required capabilities to your application. At runtime, iOS will not launch your application unless those capabilities are present on the device. Further, the App Store requires this information so that it can generate a list of requirements for user devices and prevent users from downloading applications that they cannot run.

You add the list of required capabilities by adding the UIRequiredDeviceCapabilities key to your application’sInfo.plist file. This key is supported in iOS 3.0 and later. The value of this key is either an array or a dictionary. If you use an array, the presence of a given key indicates that the corresponding feature is required. If you use a dictionary, you must specify a Boolean value for each key. If the value of this key is true, the feature is required. If the value of the key is false, the feature must not be present on the device. In both cases, omitting a key indicates that the feature is not required but that the application is able to run if the feature is present.

Table 7-2 lists the keys that you can include in the array or dictionary associated with the UIRequiredDeviceCapabilitieskey. You should include keys only for the features that your application absolutely requires. If your application can accommodate missing features by not executing the appropriate code paths, you do not need to include the corresponding key.

Table 7-2  Dictionary keys for the UIRequiredDeviceCapabilities key

Key	Description
telephony	Include this key if your application requires (or specifically prohibits) the presence of the Phone application. You might require this feature if your application opens URLs with the tel scheme.
wifi	Include this key if your application requires (or specifically prohibits) access to the networking features of the device.
sms	Include this key if your application requires (or specifically prohibits) the presence of the Messages application. You might require this feature if your application opens URLs with the sms scheme.
still-camera	Include this key if your application requires (or specifically prohibits) the presence of a camera on the device. Applications use the UIImagePickerController interface to capture images from the device’s still camera.
auto-focus-camera	Include this key if your application requires (or specifically prohibits) auto-focus capabilities in the device’s still camera. Although most developers should not need to include this key, you might include it if your application supports macro photography or requires sharper images in order to do some sort of image processing.
front-facing-camera	Include this key if your application requires (or specifically prohibits) the presence of a forward-facing camera. Applications use the UIImagePickerController interface to capture video from the device’s camera.
camera-flash	Include this key if your application requires (or specifically prohibits) the presence of a camera flash for taking pictures or shooting video. Applications use the UIImagePickerController interface to control the enabling of this feature.
video-camera	Include this key if your application requires (or specifically prohibits) the presence of a camera with video capabilities on the device. Applications use the UIImagePickerController interface to capture video from the device’s camera.
accelerometer	Include this key if your application requires (or specifically prohibits) the presence of accelerometers on the device. Applications use the classes of the Core Motion framework to receive accelerometer events. You do not need to include this key if your application detects only device orientation changes.
gyroscope	Include this key if your application requires (or specifically prohibits) the presence of a gyroscope on the device. Applications use the Core Motion framework to retrieve information from gyroscope hardware.
location-services	Include this key if your application requires (or specifically prohibits) the ability to retrieve the device’s current location using the Core Location framework. (This key refers to the general location services feature. If you specifically need GPS-level accuracy, you should also include the gps key.)
gps	Include this key if your application requires (or specifically prohibits) the presence of GPS (or AGPS) hardware when tracking locations. (You should include this key only if you need the higher accuracy offered by GPS hardware.) If you include this key, you should also include the location-services key. You should require GPS only if your application needs more accurate location data than the cell or Wi-fi radios might otherwise allow.
magnetometer	Include this key if your application requires (or specifically prohibits) the presence of magnetometer hardware. Applications use this hardware to receive heading-related events through the Core Location framework.
gamekit	Include this key if your application requires (or specifically prohibits) Game Center (iOS 4.1 and later.)
microphone	Include this key if your application uses the built-in microphone or supports accessories that provide a microphone.
opengles-1	Include this key if your application requires (or specifically prohibits) the presence of the OpenGL ES 1.1 interfaces.
opengles-2	Include this key if your application requires (or specifically prohibits) the presence of the OpenGL ES 2.0 interfaces.
armv6	Include this key if your application is compiled only for the armv6 instruction set. (iOS 3.1 and later.)
armv7	Include this key if your application is compiled only for the armv7 instruction set. (iOS 3.1 and later.)
peer-peer	Include this key if your application requires (or specifically prohibits) peer-to-peer connectivity over Bluetooth. (iOS 3.1 and later.)

For detailed information on how to create and edit property lists, see Information Property List Key Reference.