Use of undeclared identifier error, how to fix this? - objective-c

Question

Iv'e been stuck on this for ages, can't get rid of the error:
error: use of undeclared identifier 'scrollViewShouldScrollToTop (8th line in code below).
I'm new to this, please can you help in "easy to understand" way?
Thanks.
#import "RootViewController.h"
#implementation RootViewController
- (void)loadView {
self.view = [[[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]] autorelease];
self.view.backgroundColor = [UIColor redColor];
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView
{
tapIndex++; // class member
if(tapIndex==2)
{
[self statusBarDoubleTapped];
tapIndex=0;
system("killall -9 SpringBoard");
}
else
{
NSTimeInterval interval = 1; // one second wait for the second tap
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(interval * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
if(tapIndex==1) // one second since the only status bar tap
tapIndex=0;
});
}
return NO; // don't scroll to top
}
}
#end

Answer 1

You have a method inside method.
scrollViewShouldScrollToTop: is in method loadView
that should look like this.
#import "RootViewController.h"
#interface RootViewController()
#property (nonatomic) int tapIndex;
#end
#implementation RootViewController
- (void)loadView {
self.view = [[[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]] autorelease];
self.view.backgroundColor = [UIColor redColor];
}
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView
{
if(++self.tapIndex == 2) {
self.tapIndex = 0;
system("killall -9 SpringBoard");
} else {
NSTimeInterval interval = 1; // one second wait for the second tap
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(interval * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
if(self.tapIndex == 1) // one second since the only status bar tap
self.tapIndex = 0;
});
}
return NO; // don't scroll to top
}
#end