UIScrollview does not react to any touch? - ios

Question

I am trying to do a simple scroll, but the views do not move after a touch, I am not sure why, the scrollview should handle the gesture, but something might be missing. Would someone know where?
Here is the code : I create a small horizontal scroll view, with some views inside. The views appear well, I am testing it on a device for the touch :
- (void)viewDidLoad {
[super viewDidLoad];
//horizontal scroll view
HorizScroll *ho = [[HorizScroll alloc] initWithFrame:CGRectMake(0, 0, 500, 100)];
for ( int i=0; i<3; i++){
MyView* mv = [[MyView alloc] init];
[ho addSubview:mv];
}
//ho.zoomScale = 0.3f;
[self.view addSubview:ho];
}
#implementation HorizScroll
- (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
}
return self;
}
-(void)addSubview:(UIView *)view{
[super addSubview:view];
NSUInteger numSubviews = self.subviews.count;
[view setFrame:CGRectMake(CGRectGetWidth(view.bounds)*(numSubviews),
0,
CGRectGetWidth(view.bounds),
CGRectGetHeight(view.bounds) )];
[self setContentSize:CGSizeMake(CGRectGetWidth(view.bounds)*(numSubviews),
CGRectGetHeight(view.bounds) )];
}
#implementation MyView
-(int)getRandomNumberBetween:(int)from to:(int)pto {
return (int)(from + arc4random() % (pto-from+1));
}
-(instancetype)init{
if ( self = [super init] ){
CGFloat red = [self getRandomNumberBetween:1 to:255];
self.backgroundColor = [UIColor colorWithRed:red/256.0
green:[self getRandomNumberBetween:1 to:255]/256.0
blue:[self getRandomNumberBetween:1 to:255]/256.0
alpha:1.0];
}
return self;
}
-(instancetype)initWithFrame:(CGRect)frame{
if ( self = [super initWithFrame:frame] ){
self.frame = CGRectMake(counterX, 0, 100, 100);
counterX += 50;
}
return self;
}

Answer 1

You need to set contentSize of scrollview to be larger than its frame size. so add this line after [self.view addSubview:ho].
ho.contentSize = CGSizeMake(501.f, 100.f);
or before [self.view addSubview:ho] and comment out the line:
[self setContentSize:CGSizeMake(CGRectGetWidth(view.bounds)*(numSubviews),
CGRectGetHeight(view.bounds))];
which is not necessary since you can set it after all subviews are added.