How to know if iPhone camera is ready to take picture?

iphone, uiimagepickercontroller

Solution

As @djromero said there is a solution by using `AVFoundation` (but not instead of `UIImagePickerController`. You just use `AVFoundation` to get a notification back).

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(cameraIsReady:)
                                             name:AVCaptureSessionDidStartRunningNotification object:nil];

And then, once the camera is ready you got your notification:

- (void)cameraIsReady:(NSNotification *)notification
{   
    NSLog(@"Camera is ready...");
    // Whatever
}

I have just tested it by calling `takePicture` after `UIImagePickerController` presentation (where I got the 'camera is not ready' message) and right inside my notification callback, where it worked like a charm.

Side-note:

`[camera isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]` always returns `Yes` because it only checks that there is a camera device available. As a matter of fact, Apple recommends that you always must check that this returns `Yes` and that you have a non nil delegate (to provide a way to `dismiss` the picker through the standard interface) before you try to initialize and present the controller.

Problem

When `[camera takePicture]` is called before the camera is ready, it spits out this message: `UIImagePickerController: ignoring request to take picture; camera is not yet ready.` How can I know when it is ready to take a photo? `[camera isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]` always returns true, even when it's apparently not ready.

Original source