objective c - Cannot find protocol declaration in Xcode -

i've experienced today while i'm building app. i've declared protocol in myobject1 , add delegate property on it. i've assign myobject2 delegate of myobject1. i've added in way usual

@interface myobject2 : uiviewcontroller <delegateofobject1>

but xcode says protocol declaration cannot found. i've check code i've declared protocol. i've try assign myobject2 delegate of other object. i've edit code this

@interface myobject2 : uiviewcontroller <uitableviewdelegate,delegateofobject1>

but xcode again cannot found declaration of protocol of delegateofobject1. i've tried delete delegateofobject1 on code , add assign myobject delegate of other object , goes this.

@interface myobject2 : uiviewcontroller <uitableviewdelegate,uitabbardelegate>

no errors have been found. i've tried again add again delegateofobject1 in code

@interface myobject2 : uiviewcontroller <uitableviewdelegate,uitabbardelegate,delegateofobject1>

at time xcode did not find error on code. tried again remove uitableviewdelegate , uitabbardelegate on code.

@interface myobject2 : uiviewcontroller <delegateofobject1>

at time no error had found same code i've write before. should cause of stuff on code?

thanks...

the error caused due import loop.