iOS 5 Programming Cookbook

11.1. Detecting and Probing the Camera

Problem

You want to know whether the iOS device running your application has a camera that you can access. This is an important check to make before attempting to use the camera, unless you are sure your application will never run on a device that lacks one.

Solution

Use the isSourceTypeAvailable: class method of UIImagePickerController with the UIImagePickerControllerSourceTypeCamera value, like so:

- (BOOL) isCameraAvailable{
  
  return [UIImagePickerController isSourceTypeAvailable:
          UIImagePickerControllerSourceTypeCamera];
  
}

- (BOOL)            application:(UIApplication *)application
  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
  
  if ([self isCameraAvailable]){
    NSLog(@"Camera is available.");
  } else {
    NSLog(@"Camera is not available.");
  }
  
  self.window = [[UIWindow alloc] initWithFrame:
                 [[UIScreen mainScreen] bounds]];
  
  self.window.backgroundColor = [UIColor whiteColor];
  [self.window makeKeyAndVisible];
  return YES;
}

Discussion

Before attempting to display an instance of UIImagePickerController to your user for taking photos or shooting videos, you must detect whether the device supports that interface. The isSourceTypeAvailable: class method allows you to determine three sources of data:

• The camera, by passing the UIImagePickerControllerSourceTypeCamera value to this method.

• The Photo Library, by passing the UIImagePickerControllerSourceTypePhotoLibrary value to this method. This browses the root folder of the Photos directory on the device.

• The camera ...