創建一個自定義的UIScrollView Scroller

Question

好吧，我已經遍及互聯網試圖找到答案，我正在嘗試創建一個自定義的UIScrollView滾動器。

這裏是一個滾輪

http://postimage.org/image/cg2jvde9z/

http://postimage.org/image/ko0mp3kdj/ 的圖片的鏈接（即白盒只是對我來說，測試滾動型）

我已經得到了滾輪的工作，儘管我需要幫助確定滾動視圖每次滾動滾動條時應移動多少像素

這裏是一些代碼

-(IBAction)scroller_bar:(id)sender withEvent:(UIEvent *)event{  
UIButton *button_sent = (UIButton *)sender; 

UITouch *touch = [[event touchesForView:button_sent] anyObject]; 

CGPoint previousLocation = [touch previousLocationInView:button_sent]; 
CGPoint location = [touch locationInView:button_sent]; 
CGFloat delta_x = location.x - previousLocation.x; 
float left_side = button_sent.center.x + delta_x; 
float right_side = button_sent.center.x + delta_x; 
if (right_side > button_sent.center.x) { 
    scroll_right = YES; 
} 
else{ 
    scroll_right = NO; 
} 
if (left_side <= 13 + 50.5 || right_side >= 307 - 50.5) { 

} 
else{ 
    button_sent.center = CGPointMake(button_sent.center.x + delta_x, 
            button_sent.center.y); 

    if (scroll_right) { 

    [selection_scroll setContentOffset:CGPointMake(selection_scroll.contentOffset.x - (Help HERE!), selection_scroll.contentOffset.y) animated:YES]; 
    } 
    else{ 

     [selection_scroll setContentOffset:CGPointMake(selection_scroll.contentOffset.x + (Help HERE!), selection_scroll.contentOffset.y) animated:YES]; 


    } 
} 

}

在上面的代碼，你會看到一個「（幫助在這裏！）」，

這正是我試圖找出有多少像素的，我應該移動滾動視圖。這是一個令人困惑的問題，希望你能理解。

謝謝:)

Answer 1

我不知道蘋果是否會批准這個或沒有，但下面寫的代碼可以改變scollView的滾動圖片

for (UIImageView *img in yourscrollView.subviews) { 
    [img setImage:[UIImage imageNamed:@"your custom scroller image"]]; 
}