Custom UIView not receiving touch events - ios

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;

Answer 2

If userInteractionEnabled trick not works maybe you should check the view's parentview autosizing attributes.
I changed it like this see below, because storyboard loaded it 'originally' in portrait mode, but I presented it in landscape, so the parent's view height become 0 px. And even dow the view itself kept its height the parents become 0 px so view did not get the event.

Answer 3

This is probably a super edge case, but I had this problem when accidentally had my custom view class descend from UICollectionViewCell in code, but in the XIB it the element used was UIView.

Answer 4

I've seen this line cause trouble with UIView events:
contentView.translatesAutoresizingMaskIntoConstraints = NO;
This line can cause headaches after you've pushed and popped a view controller, using the pushViewController and popViewControllerAnimated methods. Once your contentView is displayed again, you may find event handling doesn't work.