Three things are being declared here: an anonymous enumerated type is declared, ShapeType is being declared a typedef for that anonymous enumeration, and the three names kCircle, kRectangle, and kOblateSpheroid are being declared as integral constants. Let’s break that down. In the simplest case, an enumeration can be declared as enum tagname { … }; … Read more
An option: [NSString stringWithFormat:@”%@/%@/%@”, one, two, three]; Another option: I’m guessing you’re not happy with multiple appends (a+b+c+d), in which case you could do: NSLog(@”%@”, [Util append:one, @” “, two, nil]); // “one two” NSLog(@”%@”, [Util append:three, @”https://stackoverflow.com/”, two, @”https://stackoverflow.com/”, one, nil]); // three/two/one using something like + (NSString *) append:(id) first, … { NSString … Read more
NSString *string = @”hello bla bla”; if ([string rangeOfString:@”bla”].location == NSNotFound) { NSLog(@”string does not contain bla”); } else { NSLog(@”string contains bla!”); } The key is noticing that rangeOfString: returns an NSRange struct, and the documentation says that it returns the struct {NSNotFound, 0} if the “haystack” does not contain the “needle”. And if … Read more
Solution The compiler is warning about this for a reason. It’s very rare that this warning should simply be ignored, and it’s easy to work around. Here’s how: if (!_controller) { return; } SEL selector = NSSelectorFromString(@”someMethod”); IMP imp = [_controller methodForSelector:selector]; void (*func)(id, SEL) = (void *)imp; func(_controller, selector); Or more tersely (though hard … Read more
Compare method Either you implement a compare-method for your object: – (NSComparisonResult)compare:(Person *)otherObject { return [self.birthDate compare:otherObject.birthDate]; } NSArray *sortedArray = [drinkDetails sortedArrayUsingSelector:@selector(compare:)]; NSSortDescriptor (better) or usually even better: NSSortDescriptor *sortDescriptor; sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@”birthDate” ascending:YES]; NSArray *sortedArray = [drinkDetails sortedArrayUsingDescriptors:@[sortDescriptor]]; You can easily sort by multiple keys by adding more than one to … Read more
It is possible to disable ARC for individual files by adding the -fno-objc-arc compiler flag for those files. You add compiler flags in Targets -> Build Phases -> Compile Sources. You have to double click on the right column of the row under Compiler Flags. You can also add it to multiple files by holding … Read more
This question seems to be very popular here on Stack Overflow so I thought I would try and give a better answer to help out people starting in the world of iOS like me. Passing Data Forward Passing data forward to a view controller from another view controller. You would use this method if you wanted … Read more
You will only need a ScrollView if the contents you have now do not fit in the iPhone screen. (If you are adding the ScrollView as the superview of the components just to make the TextField scroll up when keyboard comes up, then it’s not needed.) The standard way to prevent the TextFields from being … Read more
The last two are identical; “atomic” is the default behavior (note that it is not actually a keyword; it is specified only by the absence of nonatomic — atomic was added as a keyword in recent versions of llvm/clang). Assuming that you are @synthesizing the method implementations, atomic vs. non-atomic changes the generated code. If … Read more