objective c - Custom delegate does not working in iOS -

my custom delegate not work. used custom delegate time it's not working. want pass data (uislider value after change) uiviewcontroller class subclass of uiview. here code. please me out. -

ratingviewcontroller.h -

#import <uikit/uikit.h>  @class starratingview; //define class, protocol can see class  @protocol delegateforslider <nsobject>   //define delegate protocol  - (void) getvalue:(cgfloat) value;  //define delegate method implemented within class  @end   @interface ratingviewcontroller : uiviewcontroller  @property (nonatomic, weak) id <delegateforslider> delegate; //define delegateforslider delegate @property (weak, nonatomic) iboutlet uiview *ratingview; - (ibaction)slidervaluechange:(id)sender; @property (weak, nonatomic) iboutlet uislider *slider;  @end 

ratingviewcontroller.m -

#import "ratingviewcontroller.h" #import "starratingview.h"  @interface ratingviewcontroller ()  @end  @implementation ratingviewcontroller  - (void)viewdidload {     [super viewdidload];     // additional setup after loading view.      starratingview* starviewwithanimated = [[starratingview alloc]initwithframe:cgrectmake(5, 8, 100, 50) andrating:49];     [self.ratingview addsubview:starviewwithanimated]; }  - (ibaction)slidervaluechange:(id)sender {     nslog(@"value changed");     [self.delegate getvalue:self.slider.value]; }  @end 

and in class want uislider value. starratingview.h -

#import <uikit/uikit.h> #import "ratingviewcontroller.h"  @interface starratingview : uiview <delegateforslider>  - (id)initwithframe:(cgrect)frame andrating:(int)rating;  @end 

starratingview.m -

#import "starratingview.h"  @interface starratingview()  @property (strong, nonatomic) ratingviewcontroller *ratingviewcontroller; @property (nonatomic, strong) uilabel* label;  @end  @implementation starratingview  - (id)initwithframe:(cgrect)frame andrating:(int)rating {     self = [super initwithframe:frame];     if (self) {         _ratingviewcontroller.delegate = self;          //add label after star view show rating percentage         self.label = [[uilabel alloc]initwithframe:cgrectmake(0, 0,frame.size.width, frame.size.height)];         self.label.font = [uifont systemfontofsize:18.0f];         self.label.text = [nsstring stringwithformat:@"%d%%",rating];         self.label.textalignment = nstextalignmentright;         self.label.textcolor = [uicolor whitecolor];         self.label.backgroundcolor = [uicolor bluecolor];         [self addsubview:self.label];     }      return self; }  -(void) getvalue:(cgfloat)value {     nslog(@"got value : %f", value);//this line print nothing, mean never fire }  @end 

you need set delegate in ratingviewcontroller.m's viewdidload method. delegate isn't being set because when initwithframe:andrating: called, _ratingviewcontroller nil.

also, bad practice have reference uiviewcontroller in uiview. not create retain cycle, ignores half reason of using delegates: add flexibility object conforms delegateforslider can set starratingview's delegate property.

for more information on delegation check out this programming overflow post , apple's docs