No known class method for selector when using blocks - ios

Question

i am new to use block syntax and facing the below problem. The below code is calling another static method of a class that causing the problem. below code is called from click of next button on bar . is there any mistake on the syntax of this code?
-(BOOL) shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender
{
if (![sender isKindOfClass:[UIBarButtonItem class] ]) {
return true;
}
// Trim the spaces
self.stewardsNameTextField.text = [self.stewardsNameTextField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet] ];
self.trackNameTextField.text = [self.trackNameTextField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet] ];
self.curatorNameTextField.text = [self.curatorNameTextField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet] ];
bool isValid =[JLTValidator validateFields: #[self.stewardsNameTextField, self.trackNameTextField, self.curatorNameTextField, self.weatherConditionSegment, self.trackConditionSegment] withScrollToCallback: ^(UIView * invalidField) // problem is here. Is this incorrect syntax?
{
if (invalidField == self.stewardsNameTextField || invalidField == self.trackNameTextField || invalidField == self.curatorNameTextField)
{
[invalidField becomeFirstResponder];
}
else
{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
CGPoint top = CGPointMake(0, invalidField.frame.origin.y - 90);
[_scrollView setContentOffset:top animated:YES];
_scrollView.scrollIndicatorInsets=contentInsets;
}
if (!isValid) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Sorry!" message:#"Please fill out the marked fields." delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
}
return isValid;
}];
}
The definition of the static method being called to the class:
+(BOOL)validateFields:(NSArray *)fields
{
return [JLTValidator validateFields:fields withScrollToCallback:nil];
}
+(BOOL)validateFields:(NSArray *)fields andShouldDisplayMessage : (bool) shouldDisplayMessage
{
return [JLTValidator validateFields:fields withScrollToCallback:nil andShouldDisplayMessage:shouldDisplayMessage];
}
+(BOOL)validateFields:(NSArray *)fields withScrollToCallback : (void (^) (UIView *))scrollToCallback
{
return [JLTValidator validateFields:fields withScrollToCallback:scrollToCallback andShouldDisplayMessage:true];
}
+(BOOL)validateFields:(NSArray *)fields withScrollToCallback : (void (^) (UIView *))scrollToCallback andShouldDisplayMessage : (bool) shouldDisplayMessage
{
}
Whats wrong here? pls guide.

Answer 1

+(BOOL)validateFields:(NSArray *)fields withScrollToCallback : (void (^) (UIView *))scrollToCallback
The block parameter in this method doesn't return anything (you can see 'void' there). So if inside the block, you return BOOL value (isValid) is incorrect. Moreover, you returned the value that you're trying to get (isValid = ..... isValid) which is also a mistake.
I don't know what u're trying inside the block, but to solve this, you can do like below:
bool isValid =[JLTValidator validateFields: #[self.stewardsNameTextField, self.trackNameTextField, self.curatorNameTextField, self.weatherConditionSegment, self.trackConditionSegment] withScrollToCallback: ^(UIView * invalidField) // problem is here. Is this incorrect syntax?
{
if (invalidField == self.stewardsNameTextField || invalidField == self.trackNameTextField || invalidField == self.curatorNameTextField)
{
[invalidField becomeFirstResponder];
}
else
{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
CGPoint top = CGPointMake(0, invalidField.frame.origin.y - 90);
[_scrollView setContentOffset:top animated:YES];
_scrollView.scrollIndicatorInsets=contentInsets;
}
}];
if (!isValid) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Sorry!" message:#"Please fill out the marked fields." delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
}