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近来,项目中需要定制UIPageControl样式,目前知道的方式大概如下,这里简单概括:
一、修改颜色,最简单的方式:
// 设置非选中页的圆点颜色
_pageControl.pageIndicatorTintColor = [UIColor redColor];
// 设置选中页的圆点颜色
_pageControl.currentPageIndicatorTintColor = [UIColor blueColor];
二、修改静态图标样式,可以采用KVO方式,这种弊端是只能静态显示,无法动态替换,且私有,危险:
[_pageControl setValue:[UIImage imageNamed:@"image1"] forKeyPath:@"_pageImage"];
[_pageControl setValue:[UIImage imageNamed:@"image2"] forKeyPath:@"_currentPageImage"];
三、替换系统默认图标,自定义样式:
常规方式便是创建一个类,继承于UIPageControl,重新set方式,这里写下核心代码,也是目前网络上的方式:
-(void) updateDots {
for (int i = 0; i < [self.subviews count]; i++)
{
UIImageView *dot = [self.subviews objectAtIndex:i];
if (i == self.currentPage) {
dot.image = activeImage;
}
else
dot.image = inactiveImage;
}
结果是程序崩溃,归咎原因:
这种方式及其危险的,因为[self.subviews objectAtIndex:i] class 为UIView, 而 UIImageView *dot = [self.subviews objectAtIndex:i]; 这句是将一个UIView转换为UIImageView, 故容易crash 掉,特此放弃如上国内方式;
四、完善上面第三种方式,转为安全的替换方式,核心代码如下:
for (UIView *subview in view.subviews) {
if ([subview isKindOfClass:[UIImageView class]]) {
dot = (UIImageView *)subview;
break;
}
}
采用如上安全方式,可有效防止崩溃,至此完成项目需求,效果如下:
image五、这里把整个代码放出来,帮助大家少走弯路,具体代码如下:
1、.h文件
#import <UIKit/UIKit.h>
@interface CustomPageControl : UIPageControl
@property (nonatomic, strong) UIImage *currentImage;
@property (nonatomic, strong) UIImage *inactiveImage;
@property (nonatomic, assign) CGSize currentImageSize;
@property (nonatomic, assign) CGSize inactiveImageSize;
@end
2、.m文件
#import "CustomPageControl.h"
@implementation CustomPageControl
- (instancetype)init{
self = [super init];
if (self) {
self.userInteractionEnabled = NO;
}
return self;
}
- (void)setCurrentPage:(NSInteger)currentPage{
[super setCurrentPage:currentPage];
[self updateDots];
}
- (void)updateDots{
for (int i = 0; i < [self.subviews count]; i++) {
UIImageView *dot = [self imageViewForSubview:[self.subviews objectAtIndex:i] currPage:i];
if (i == self.currentPage){
dot.image = self.currentImage;
dot.size = self.currentImageSize;
}else{
dot.image = self.inactiveImage;
dot.size = self.inactiveImageSize;
}
}
}
- (UIImageView *)imageViewForSubview:(UIView *)view currPage:(int)currPage{ UIImageView *dot = nil;
if ([view isKindOfClass:[UIView class]]) {
for (UIView *subview in view.subviews) {
if ([subview isKindOfClass:[UIImageView class]]) {
dot = (UIImageView *)subview;
break;
}
}
if (dot == nil) {
dot = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, view.frame.size.width, view.frame.size.height)];
[view addSubview:dot];
}
}else {
dot = (UIImageView *)view;
}
return dot;
}
@end
3、使用方式:
CustomPageControl *pageCtrl = [[CustomPageControl alloc] initWithFrame:CGRectMake(0, 10, mScreenWidth, 5)];
[pageCtrl.numberOfPages = cardSwitchViewAry.count;
pageCtrl.currentPage = 0;
pageCtrl.userInteractionEnabled = NO;
pageCtrl.inactiveImage = [UIImage imageNamed:@"ex_page_1"];
pageCtrl.inactiveImageSize = CGSizeMake(5, 5);
pageCtrl.currentImage = [UIImage imageNamed:@"ex_page_2"];
pageCtrl.currentImageSize = CGSizeMake(10, 5);
//去掉系统自带样式
pageCtrl.currentPageIndicatorTintColor = [UIColor clearColor];
pageCtrl.pageIndicatorTintColor = [UIColor clearColor];
至此,定制UIPageControl的正确姿势已了解,希望对大家有用。
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