Question

I am building a custom slider to my application.

I found a library on Github as inspiration.

I have created the file: NKSlider as a subclass of UIView and implemented on it the drawRect as the library did and implemented the methods: touchesMoved:withEvent: and touchesBegan:withEvent:. But none of the touches events are being called.

this is how i add this custom view to my view controller:

NKHandler *nk = [[NKHandler alloc] init];
nk.frame = CGRectMake(20, 20, 280, 36);
[self.view addSubview:nk];
[self.view addSubview:[[NKHandler alloc] initWithFrame:CGRectMake(20, 60, 280, 100)]];

and this are the classes. What am i doing wrong??

the .h

#import <UIKit/UIKit.h>

@interface NKHandler : UIView

@end

and .m

#import "NKHandler.h"

static inline CGPoint CGPointTopCenter(CGRect rect) {
  CGPoint p; p.x = rect.origin.x + (rect.size.width / 2); p.y = rect.origin.y; return p;
}
static inline CGPoint CGPointBottomCenter(CGRect rect) {
  CGPoint p; p.x = rect.origin.x + (rect.size.width / 2); p.y = rect.origin.y + rect.size.height; return p;
}
static inline CGPoint CGPointLeftCenter(CGRect rect) {
  CGPoint p; p.x = rect.origin.x; p.y = rect.origin.y + (rect.size.height / 2); return p;
}
static inline CGPoint CGPointRightCenter(CGRect rect) {
  CGPoint p; p.x = rect.origin.x + rect.size.width; p.y = rect.origin.y + (rect.size.height / 2); return p;
}

@implementation NKHandler {
  int _selectedStep;
}

-(id)init {
  self = [super init];
  if (self) {
    self.backgroundColor = [UIColor clearColor];

    self.clipsToBounds = NO;
    self.opaque = YES;

    _selectedStep = 5;   
  }
  return self;
}

-(void) setStep:(int) step {
  _selectedStep = step;
  [self setNeedsDisplay];
}

-(void)layoutSubviews {
  ... layout stuff ...
}
-(void)drawRect:(CGRect)rect {
  ... Boring drawing stuff ..
}

#pragma mark - Touch Handling

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  NSLog(@"%s", __PRETTY_FUNCTION__);
  [self setStep:(_selectedStep+1)%11];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  NSLog(@"%s", __PRETTY_FUNCTION__);
}

@end

Answer 1

nk.userInteractionEnabled = YES;