I want to check if the iOS version of the device is greater than 3.1.3 I tried things like: [[UIDevice currentDevice].systemVersion floatValue] but it does not work, I just want a: if (version > 3.1.3) { } How can I achieve this? 36 s 36
How do I convert an NSString value to NSData? 14 s 14 NSString* str = @”teststring”; NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding];
I’m updating an old app with an AdBannerView and when there is no ad, it slides off screen. When there is an ad it slides on the screen. Basic stuff. Old style, I set the frame in an animation block. New style, I have a IBOutlet to the auto-layout constraint which determines the Y position, … Read more
I’m developing a Cocoa application, and I’m using constant NSStrings as ways to store key names for my preferences. I understand this is a good idea because it allows easy changing of keys if necessary. Plus, it’s the whole ‘separate your data from your logic’ notion. Anyway, is there a good way to make these … Read more
In Swift, how does one call Objective-C code? Apple mentioned that they could co-exist in one application, but does this mean that one could technically re-use old classes made in Objective-C whilst building new classes in Swift? 17 s 17 Using Objective-C Classes in Swift If you have an existing class that you’d like to … Read more
I don’t think I fundamentally understand what an enum is, and when to use it. For example: typedef enum { kCircle, kRectangle, kOblateSpheroid } ShapeType; What is really being declared here? 13 s 13 Three things are being declared here: an anonymous enumerated type is declared, ShapeType is being declared a typedef for that anonymous … Read more
Are there any shortcuts to (stringByAppendingString:) string concatenation in Objective-C, or shortcuts for working with NSString in general? For example, I’d like to make: NSString *myString = @”This”; NSString *test = [myString stringByAppendingString:@” is just a test”]; something more like: string myString = “This”; string test = myString + ” is just a test”; 30 … Read more
How can I check if a string (NSString) contains another smaller string? I was hoping for something like: NSString *string = @”hello bla bla”; NSLog(@”%d”,[string containsSubstring:@”hello”]); But the closest I could find was: if ([string rangeOfString:@”hello”] == 0) { NSLog(@”sub string doesnt exist”); } else { NSLog(@”exists”); } Anyway, is that the best way to … Read more
I’m getting the following warning by the ARC compiler: “performSelector may cause a leak because its selector is unknown”. Here’s what I’m doing: [_controller performSelector:NSSelectorFromString(@”someMethod”)]; Why do I get this warning? I understand the compiler can’t check if the selector exists or not, but why would that cause a leak? And how can I change … Read more
What I want to do seems pretty simple, but I can’t find any answers on the web. I have an NSMutableArray of objects, and let’s say they are ‘Person’ objects. I want to sort the NSMutableArray by Person.birthDate which is an NSDate. I think it has something to do with this method: NSArray *sortedArray = … Read more
