@interface ViewController ()<UIScrollViewDelegate>

{

    UIScrollView *backScrollView;

    UIImageView *scrollIndexerImageView;

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    backScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(10, 20, 200, 300)];

    backScrollView.backgroundColor = [UIColor greenColor];

    backScrollView.contentSize = CGSizeMake(200, 900);

    backScrollView.showsHorizontalScrollIndicator = NO;

    backScrollView.showsVerticalScrollIndicator = NO;

    backScrollView.delegate = self;

    [self.view addSubview:backScrollView];

    scrollIndexerImageView = [[UIImageView alloc] initWithFrame:CGRectMake(backScrollView.frame.size.width-8, 0, 8,30)];

    scrollIndexerImageView.image = [UIImage imageNamed:@"teacherlist_select_scrollbar"];

    [backScrollView addSubview:scrollIndexerImageView];

}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView

{

    float p = 0;

    p = scrollView.contentOffset.y/(scrollView.contentSize.height - scrollView.frame.size.height+(scrollIndexerImageView.frame.size.height-scrollIndexerImageView.frame.size.height*scrollView.frame.size.height/scrollView.contentSize.height));

    scrollIndexerImageView.frame = CGRectMake(backScrollView.frame.size.width-8,p*scrollView.contentSize.height,8,30);

    NSLog(@"y:%f",scrollView.contentOffset.y);

    NSLog(@"--:%f",scrollIndexerImageView.frame.origin.y);

}

原文地址：http://www.wahenzan.com/a/mdev/ios/2014/1215/350.html

UIScrollview一直显示滚动条，使用UIImageView自定义滚动条