Basic Sensors in iOS

Detecting Hardware Differences

Because your application will likely support multiple devices, you’ll need to write code to check which features are supported and adjust your application’s behavior as appropriate.

Camera Availability

We cover the camera in detail in Chapter 2, however it is simple matter to determine whether a camera is present in the device:

BOOL available = [UIImagePickerController
  isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];

Once you have determined that a camera is present you can enquire whether it supports video by making a call to determine the available media types the camera supports:

NSArray *media = [UIImagePickerController availableMediaTypesForSourceType:
                  UIImagePickerControllerSourceTypeCamera];

If the kUTTypeMovie media type is returned as part of the array, then the camera will support video recording:

if ( [media containsObject:(NSString *)kUTTypeMovie ] ){
    NSLog(@"Camera supports movie capture.");
}

Audio Input Availability

An initial poll of whether audio input is available can be done using the AVAudioSession class by checking the inputIsAvailable class property:

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
BOOL audioAvailable = audioSession.inputIsAvailable;

Note

You will need to add the AVFoundation.Framework (right-click/Control-click on the Frameworks folder in Xcode, then choose Add→Existing Frameworks). You’ll also need to import the header (put this in your declaration if you plan to implement the AVAudioSessionDelegate ...