iOS系統中，UipageControl默認的樣式如下：
在業務開發過程中，很多時候都需要自定義UIPageControl圓點的展示樣式及圓點之間的間隔。在網上搜索了如何自定義UIPageControl，比比皆是下面的實現方式：
//自定義一個UIPageControl的子類-(void) updateDots{ for (int i = 0; i < [self.subviews count]; i++) { UIImageView* dot = [self.subviews objectAtIndex:i]; if (i == self.currentPage) { if(i==0) { dot.image = [UIImage imageNamed:@"activesearch.png"]; } else { dot.image = activeImage; } } else { if(i==0) { dot.image = [UIImage imageNamed:@"inactivesearch.png"]; } else { dot.image = inactiveImage; } } }}-(void)setCurrentPage:(NSInteger)page{ [super setCurrentPage:page]; [self updateDots];}但是將其運用到實踐中，會引起崩潰，原因是UIPageControl subviews中的對象并不是UIImageView的實例，而是UIView的實例。
遍歷subviews數組：
for (int i = self.subviews.count - 1; i >= 0; --i) { UIView *dotView = [self.subviews objectAtIndex:i]; }打印dotView:
<UIView: 0x7fa47ae99ab0; frame = (193 1.5; 7 7); layer = <CALayer: 0x6080004321a0>>從中只能看見frame信息，并不知道原點樣式是如何設置的，進一步打印dotView.layer:
//非活動態<CALayer:0x6080004321a0; position = CGPoint (196.5 5); bounds = CGRect (0 0; 7 7); delegate = <UIView: 0x7fa47ae99ab0; frame = (193 1.5; 7 7); layer = <CALayer: 0x6080004321a0>>; opaque = YES; allowsGroupOpacity = YES; cornerRadius = 3.5; backgroundColor = <CGColor 0x60800029ed20> [<CGColorSpace 0x608000036320> (kCGColorSpaceICCBased; kCGColorSpaceModelMonoChrome; 普通灰度系數 2.2 描述文件; extended range)] ( 1 0.2 )>//活動態<CALayer:0x6000004286c0; position = CGPoint (0 0); bounds = CGRect (0 0; 7 7); delegate = <UIView: 0x7ff7b8c87e30; frame = (-3.5 -3.5; 7 7); layer = <CALayer: 0x6000004286c0>>; opaque = YES; allowsGroupOpacity = YES; cornerRadius = 3.5; backgroundColor = <CGColor 0x6000000952c0> [<CGColorSpace 0x600000227120> (kCGColorSpaceICCBased; kCGColorSpaceModelMonochrome; 普通灰度系數 2.2 描述文件; extended range)] ( 1 1 )>layer的寬高為7，cornerRadius為3.5，非活動態時backgroundColor的alpha = 0.2，活動態時alpha = 1。這就解釋了系統的樣式為什么是圓點和其活動態和非活動態下的透明度。從而得到思路可以修改UIPageControl子view的layer來修改樣式。
自定義CustomCyclePageControl繼承自UIPageControl .h文件：
#import <UIKit/UIKit.h>@interface CustomCyclePageControl : UIPageControl@PRoperty (nonatomic, strong) UIImage *activeDotImage; @property (nonatomic, strong) UIImage *inActiveDotImage;@end.m文件：
#import "CustomCyclePageControl.h"@interface CustomCyclePageControl ()@property (nonatomic, assign) NSInteger lastActivePage;@end@implementation CustomCyclePageControl- (void)updateDots { if (self.subviews.count > self.currentPage) { UIView *dotView = [self.subviews objectAtIndex:self.currentPage]; dotView.layer.contents = (id)self.activeDotImage.CGImage; dotView.layer.backgroundColor = [[UIColor whiteColor] colorWithAlphaComponent:0.6f].CGColor; if (self.lastActivePage != self.currentPage) { if (self.subviews.count > self.lastSelectedPage) { dotView = [self.subviews objectAtIndex:self.lastActivePage]; dotView.layer.contents = (id)self.inActiveDotImage.CGImage; dotView.layer.backgroundColor = [[UIColor whiteColor] colorWithAlphaComponent:0.3f].CGColor; } } }}- (void)layoutSubviews { [super layoutSubviews]; if (self.activeDotImage && self.inActiveDotImage) { CGFloat left = CGRectGetWidth(self.frame) - self.activeDotImage.size.width; CGFloat right = CGRectGetMaxX(self.frame); for (int i = self.subviews.count - 1; i >= 0; --i) { UIView *dotView = [self.subviews objectAtIndex:i]; dotView.frame = CGRectMake(left, ((CGRectGetHeight(self.frame) - self.inActiveDotImage.size.height) / 2.f), self.inActiveDotImage.size.width, self.inActiveDotImage.size.height); left -= (4 + self.inActiveDotImage.size.width); dotView.layer.cornerRadius = 0.5f; dotView.layer.contents = (id)self.inActiveDotImage.CGImage; dotView.layer.backgroundColor = [[UIColor whiteColor] colorWithAlphaComponent:0.3f].CGColor; } }}- (void)setCurrentPage:(NSInteger)currentPage { [super setCurrentPage:currentPage]; if (self.activeDotImage && self.inActiveDotImage) { [self updateDots]; self.lastActivePage = currentPage; }}@end注意：自定義時activeDotImage，inActiveDotImage都不能為nil。 自定義之后的樣式：
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