iPad universal app has method with 'not found in protocol' warning, but it works

Question

My iPad universal app has a method I implemented from here:

Best way to programmatically detect iPad/iPhone hardware

-(BOOL)isPad
{
  BOOL isPad;
  NSRange range = [[[UIDevice currentDevice] model] rangeOfString:@"iPad"];
  if(range.location==NSNotFound) isPad=NO;
  else isPad=YES;
  return isPad;
}

When I write my code like this:

if( [[[UIApplication sharedApplication] delegate] isPad] ) // do something

I get the warning:

'-isPad' not found in protocol

However, it's declared in my app delegate class:

-(BOOL)isPad;

And in the implementation (above).

Any ideas why this is?

Thanks in advance.

score 1 · Accepted Answer · answered Jul 08 '10 at 12:55

1

-delegate returns an id<UIApplicationDelegate>. Even if your app delegate supports -isPad, the UIApplicationDelegate does not, which is the warning is about.

You need to cast the return value to your class to eliminate the warning.

YourAppDelClass* appDel = [UIApplication sharedApplication].delegate;
if ([appDel isPad]) {
   ...

answered Jul 08 '10 at 12:55

kennytm

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Yes, that's how I solved it, by creating a ref variable. Thanks for the help – just_another_coder Jul 08 '10 at 13:16
Would I be able to cast it in a define statement in an h file? – just_another_coder Jul 08 '10 at 13:17
Yes - #define kIsPad [(MyAppDelegate*)[[UIApplication sharedApplication] delegate] isPad] – just_another_coder Jul 08 '10 at 13:21

score 0 · Answer 2 · answered Jul 08 '10 at 11:35

0

The compiler expects to find isPad declared in the uiapplicationdelegate protocol. Try making it an instance method of uiapplication instead.

answered Jul 08 '10 at 11:35

ennuikiller

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I made a reference variable and used that to call the method and it removed the warning. Thanks – just_another_coder Jul 08 '10 at 11:49
It would be simpler to call it the way I did it in the question, creating a ref variable every time is a pain. – just_another_coder Jul 08 '10 at 12:03

iPad universal app has method with 'not found in protocol' warning, but it works

2 Answers2