Re: accelerometer puzzle
Re: accelerometer puzzle
- Subject: Re: accelerometer puzzle
- From: David Duncan <email@hidden>
- Date: Mon, 29 Nov 2010 12:39:52 -0800
On Nov 29, 2010, at 12:31 PM, David Rowland wrote:
> When I build, I get a warning,
>
> type 'id <UIApplicationDelegate>' does not conform to the 'UIAccelerometerDelegate' protocol
Whatever is being referred to on the line you are getting this warning is only typed as "id<UIApplicationDelegate>" so the compiler doesn't know that the object actually corresponds to the UIAccelerometerDelegate protocol as well. If you know better, you can type cast to silence the warning (since I imagine you are using [[UIApplication sharedApplication] delegate] to get the value).
> Yet in running, the method is called and behaves as it should. It is the only method in the protocol, and it's optional. How could I fail to conform to the protocol?
Objective-C is a dynamic enough language that it cannot fully check for conformance at compile time (which is why the message above is a warning and not an error). Technically you don't even need to conform to the protocol, you can just implement the methods and go, but implementing the protocol allows for error checking by the compiler – but only when the compiler can actually see the protocol declarations in the first place (which is not the case above).
--
David Duncan
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