Top "Objective-c" questions

This tag should be used only on questions that are about Objective-C features or depend on code in the language.

iOS: Warning "attempt to present ViewController whose view is not in the window hierarchy"

I am getting following warning when I try to present a ActivityController on navigation controller, Attempt to present <UIActivityViewController: 0…

ios objective-c uiactivityviewcontroller presentviewcontroller uiview-hierarchy
resize superview after subviews change dynamically using autolayout

I cant for the love of god the the hang of this resizing superview. I have a UIView *superview with 4 …

ios objective-c uiview autolayout autoresize
How to get rid of the 'undeclared selector' warning

I want to use a selector on an NSObject instance without the need for an implemented protocol. For example, there's …

objective-c selector categories
What does @synchronized() do as a singleton method in objective C?

I just created a singleton method, and I would like to know what the function @synchronized() does, as I use …

objective-c ios cocoa-touch
Converting a string to an NSDate

How is it possible to convert a string to an NSDate on iOS?

objective-c cocoa-touch nsstring formatting nsdate
Setting constraints programmatically

I'm experimenting with how to use UIScrollView. After much trouble, I finally got the hang of it. But now I've …

ios objective-c uiviewcontroller uiscrollview nslayoutconstraint
How do I change the color of the text in a UIPickerView under iOS 7?

I'm aware of the pickerView:viewForRow:forComponent:reusingView method, but when using the view it passes in reusingView: how do …

ios objective-c uiview ios7 uipickerview
How can I mask a UIImageView?

I am trying to mask an image with something like this: Would you please help me? I am using this …

ios objective-c uiimage mask
NSLog/printf specifier for NSInteger?

A NSInteger is 32 bits on 32-bit platforms, and 64 bits on 64-bit platforms. Is there a NSLog specifier that always matches …

objective-c cocoa 32bit-64bit nslog nsinteger
How can I enable zoom in on UIWebView which inside the UIScrollView?

I have a UIWebView which inside a UIScrollView (scrollview contain another component) I tried to enable multitouch both on Interface …

objective-c ios cocoa-touch uiwebview zoom