How to set alignment for UIScrollView in ios - ios

Question

i am creating an application, where i am using UIScrollView for displaying the number of available colors of each product. I am getting number of available colors at run time, so i have used for loop and displaying on my scroll view. Its working fine, but the problem if i am getting only one available color then my output is coming as below screen :
But the output should be as below screen :
It seems like i need to do kind of center alignment for my UIScrollView, so every available color will suppose to display from center. here is my code :
UIScrollView *availableColorScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 80)];
availableColorScrollView.backgroundColor = [UIColor clearColor];
availableColorScrollView.showsHorizontalScrollIndicator = YES;
availableColorScrollView.showsVerticalScrollIndicator=NO;
availableColorScrollView.pagingEnabled = YES;
for (int i = 0; i < arrayAvlbleColors.count; i++) {
CGRect frame;
frame.origin.x = 23 * i;
frame.origin.y = 0;
frame.size = availableColorScrollView.frame.size;
UIView *subview = [[UIView alloc] initWithFrame:frame];
UILabel *label = [[UILabel alloc] init];
[label setFrame:CGRectMake(15, 14, 16, 16)];
[label.layer setCornerRadius:8];
NSString *strColorCode = [arrayAvlbleColors objectAtIndex:i];
strColorCode = [strColorCode substringFromIndex:1];
[label setBackgroundColor:[self colorWithHexString:strColorCode]];
[subview addSubview:label];
[availableColorScrollView addSubview:subview];
}
[self.view addSubview:availableColorScrollView];
availableColorScrollView.contentSize = CGSizeMake(24 * arrayAvlbleColors.count, availableColorScrollView.frame.size.height);
Please suggest me to achieve my output, Thanks!

Answer 1

this is the simple answer but working fine if u taken any Mainview or subview or else,
set the frame size/2 for height and width it automatically set it into center of the subview.
here i used static color , customize urself
just change your line this
NSString *strColorCode = [arrayAvlbleColors objectAtIndex:i];
strColorCode = [strColorCode substringFromIndex:1];
[label setBackgroundColor:[self colorWithHexString:strColorCode]];
[subview addSubview:label];
[availableColorScrollView addSubview:subview];
into
NSString *strColorCode = [arrayAvlbleColors objectAtIndex:i];
strColorCode = [strColorCode substringFromIndex:1];
[label setBackgroundColor:[self colorWithHexString:strColorCode]];
//use any one
//option no 1:
//[label setCenter:subview.center];
//option no 2:
[ label setCenter:CGPointMake(subview.frame.size.width / 2, subview.frame.size.height / 2)];
[subview addSubview:label];
[availableColorScrollView addSubview:subview];
final out put is

Answer 2

You can calculate your scrollview content to be placed in centre like this:
float contentWidth = 23 * arrayAvlbleColors.count;
Now you have content width to subtract from scrollView's width
float centerPadding = 0.0f;
float width = availableColorScrollView.frame.size.width;
centerPadding = width - contentWidth;
if(centerPadding < 0)
{
//content cannot be placed in center as content is bigger than width
centerPadding = 0.0f;
}
We have padding to center our content in scrollView, so use it in for loop like this :
frame.origin.x = (23 * i) + centerPadding;