xcode error iphone app "_OBJC_CLASS_$_MyView", referenced from:

I was doing the HelloWorld example and I got this error :

"_OBJC_CLASS_$_MyView", referenced from:
objc-class-ref-to-MyView in HelloWorldAppDelegate.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

After a couple of hours searching, I finally got the solution on this link:

http://iphonedevelopertips.com/xcode/linking-error-symbol-not-found.html

so, the MyView Class wasn't included in the target ¬¬...... I just included id and done :D