I'm trying to detect if the iOS device has a camera. I know there are ways to detect, but i need help making an alert, that if there is no camera, it will alert the user.

Heres my code.... its down where it takes a pic

    #import "CameraViewController.h"

@implementation CameraViewController


@synthesize imageView;
@synthesize takePictureButton;
@synthesize selectFromCameraRollButton;




/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/



// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
     [super viewDidLoad];
    /*if(! [UIImagePickerController isSourceTypeAvailable:
       UIImagePickerControllerSourceTypeCamera])
    {
        takePictureButton.hidden = YES;
        selectFromCameraRollButton.hidden = YES;
    }*/
 }



/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [imageView release];
    [takePictureButton release];
    [selectFromCameraRollButton release];
    [super dealloc];
}

 -(IBAction)getCameraPicture:(id)sender
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsImageEditing = YES;
    picker.sourceType = (sender == takePictureButton) ? UIImagePickerControllerSourceTypeCamera :
    UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    [self presentModalViewController: picker animated:YES];
    [picker release];
    upload.hidden = NO;


}

-(IBAction)selectExitingPicture
{
    if([UIImagePickerController isSourceTypeAvailable:
       UIImagePickerControllerSourceTypePhotoLibrary])
    {
        UIImagePickerController *picker= [[UIImagePickerController alloc]init];
        picker.delegate = self;
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        [self presentModalViewController:picker animated:YES];
        [picker release];
        upload.hidden = NO;

    }


}

-(void)imagePickerController:(UIImagePickerController *)picker
  didFinishPickingImage : (UIImage *)image
editingInfo:(NSDictionary *)editingInfo
{
    imageView.image = image;
    [picker dismissModalViewControllerAnimated:YES];
}


-(void)imagePickerControllerDidCancel:(UIImagePickerController *) picker
{
    [picker dismissModalViewControllerAnimated:YES];
    upload.hidden = NO;
}


- (IBAction)uploadImage {
    /*
     turning the image into a NSData object
     getting the image back out of the UIImageView
     setting the quality to 90
     */
    NSData *imageData = UIImageJPEGRepresentation(imageView.image, 90);
    // setting up the URL to post to




    //over here 
    NSString *urlString = @"/over here puut your url";

    // setting up the request object now
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"POST"];

    /*
     add some header info now
     we always need a boundary when we post a file
     also we need to set the content type

     You might want to generate a random boundary.. this is just the same 
     as my output from wireshark on a valid html post
     */
    NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
    [request addValue:contentType forHTTPHeaderField: @"Content-Type"];

    /*
     now lets create the body of the post
     */
    NSMutableData *body = [NSMutableData data];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];    
    [body appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"ipodfile.jpg\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[NSData dataWithData:imageData]];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    // setting the body of the post to the reqeust
    [request setHTTPBody:body];

    // now lets make the connection to the web
    NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

    NSLog(returnString);
}




@end

• iphone
• camera
• uialertview
• detect
• alertview

You can:

[UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary];

http://blog.mugunthkumar.com/coding/iphone-tutorial-better-way-to-check-capabilities-of-ios-devices/

Then to create an alert, just use the [[UIAlertView alloc] initWithTitle...] method, and call show on it after it is created.