ios - Swift: How to implement User Defined Runtime Attributes -

so implementing custom "chooser" toolbar, ios equivalent of radio button set (uisegmentedcontrol). horizontal bar divided options.

to this, created subclass of uicontrol called segmentedcontrol , implemented custom drawing. however, such view, need option set available options are. have accessed view controller's viewdidload() , set there, using interface builder kind of stuff.

so discovered wonderful thing called "user defined runtime attributes." created string attribute key buttonvalues , set value (this simple male/female chooser went "male|female"). found out can access these values using function self.valueforkey() , pass in key. made parser turn string array , added functionality drawrect() function use array set buttons.

when ran app, got error "key value coding-compliance."

so looked up, , found out class has have backing variables store attributes. fine, added instance variable called buttonvalues , initialized "". app runs fine value comes out empty self.valueforkey() function. looked tutorials on how set user defined runtime attributes don't go enough detail. talk key value coding-compliance it's should know.

i know must work properly, in gory detail.

for purposes can use either user-defined runtime attributes or expose class , properties editable in interface builder. either way, you'll want declare properties implicitly unwrapped optional variables -- iboutlets created same way. if need make other changes once properties have value, give them didset property observers. properties @ default value during initialization (or nil if no default set) , set when view added superview.

user defined runtime attributes

this works more or less you've described above -- here's simplest version:

class labeledview : uiview {     var viewlabel: string! {     didset {         println("didset viewlabel, viewlabel = \(self.viewlabel)")     }     }      init(coder adecoder: nscoder!)  {         super.init(coder: adecoder)         println("init coder, viewlabel = \(self.viewlabel)")     } } 

then set viewlabel attribute "hello" on view in storyboard, so:

when build & run, console show property being set correctly:

init coder, viewlabel = nil didset viewlabel, viewlabel = hello 

@ibdesignable & @ibinspectable

this gives custom view nicer interface in ib -- set @ibdesignable attribute on class , @ibinspectable attributes on each property. here's same class:

@ibdesignable class labeledview : uiview {     @ibinspectable var viewlabel: string!      init(coder adecoder: nscoder!)  {         super.init(coder: adecoder)     } } 

now can set inspectable properties @ top of attributes inspector in interface builder: