方法一：使用runtime，替换控件私有方法

#import <objc/runtime.h>

+ (void)load
{
    Method origin = class_getInstanceMethod([self class], @selector(_indicatorSpacing));
    Method custom = class_getInstanceMethod([self class], @selector(custom_indicatorSpacing));
    method_exchangeImplementations(origin, custom);
}
- (double)custom_indicatorSpacing
{
    return 6.0;
}

注意：这种方法因为调用私有API过不了app store 审核。

方法二：使用遍历控件的所有子视图，重设所有子视图的frame

- (void)setCurrentPage:(NSInteger)page {
    NSUInteger magrin = 5;
    NSUInteger count = [self.subviews count];
    NSUInteger firstX = 0;
    CGSize size;
    size.height = 5;
    size.width = 5;
    firstX = (self.frame.size.width-size.width*count-magrin*(count-1))/2;
    
    for (NSUInteger i = 0; i < count; i++) {
        UIImageView* subview = [self.subviews objectAtIndex:i];
        [subview setFrame:CGRectMake(firstX+(size.width + magrin)*i, subview.frame.origin.y, size.width,size.height)];
    }
}

参考：
http://www.cnblogs.com/chyl411/p/5421668.html
https://zhidao.baidu.com/question/563396477476563524.html