给UIScrollView添加category实现UIScrollView的轮播效果

大家都知道,要给category添加属性是必须通过runtime来实现的,本教程中给UIScrollView添加category添加了好几个属性,也是通过runtime来实现的.

实现后的效果如下:

UIScrollView的category的源码为:

UIScrollView+YX.h   +   UIScrollView+YX.m

//
//  UIScrollView+YX.h
//  PageView
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//#import <UIKit/UIKit.h>
#import "YXGCD.h"@interface UIScrollView (YX)@property (nonatomic, strong) NSNumber  *currentPage;    // 当前页码
@property (nonatomic, strong) NSNumber  *largestPage;    // 最大页码
@property (nonatomic, strong) NSNumber  *timerInterval;  // 时间间隔
@property (nonatomic, strong) GCDTimer  *timer;          // 定时器- (void)start;@end

//
//  UIScrollView+YX.m
//  PageView
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//#import "UIScrollView+YX.h"
#import <objc/runtime.h>#define  ANIMATION_DURATION   0.2@implementation UIScrollView (YX)static char timerFlag;
- (void)setTimer:(GCDTimer *)timer
{objc_setAssociatedObject(self, &timerFlag,nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);objc_setAssociatedObject(self, &timerFlag,timer,OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (GCDTimer *)timer
{return objc_getAssociatedObject(self, &timerFlag);
}static char currentPageFlag;
- (void)setCurrentPage:(NSNumber *)currentPage
{objc_setAssociatedObject(self, ¤tPageFlag,nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);objc_setAssociatedObject(self, ¤tPageFlag,currentPage,OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)currentPage
{return objc_getAssociatedObject(self, ¤tPageFlag);
}static char largestPageFlag;
- (void)setLargestPage:(NSNumber *)largestPage
{objc_setAssociatedObject(self, &largestPageFlag,nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);objc_setAssociatedObject(self, &largestPageFlag,largestPage,OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)largestPage
{return objc_getAssociatedObject(self, &largestPageFlag);
}static char timerIntervalFlag;
- (void)setTimerInterval:(NSNumber *)timerInterval
{objc_setAssociatedObject(self, &timerIntervalFlag,nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);objc_setAssociatedObject(self, &timerIntervalFlag,timerInterval,OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSNumber *)timerInterval
{return objc_getAssociatedObject(self, &timerIntervalFlag);
}- (void)start
{if (self.currentPage != nil && self.largestPage != nil && \self.timerInterval != nil && self.timer != nil){__weak UIScrollView *weakObj = self;[self.timer event:^{if (ceil(weakObj.contentOffset.x / weakObj.bounds.size.width) == \weakObj.contentOffset.x / weakObj.bounds.size.width){weakObj.currentPage       = \[NSNumber numberWithInt:weakObj.contentOffset.x / 320.f];[UIView animateWithDuration:ANIMATION_DURATION animations:^{CGPoint point         = weakObj.contentOffset;weakObj.currentPage   = \[NSNumber numberWithInt:[weakObj.currentPage intValue] + 1];point.x               = \([weakObj.currentPage intValue] % [weakObj.largestPage intValue])\*weakObj.bounds.size.width;weakObj.contentOffset = point;}];}} timeInterval:NSEC_PER_SEC * [self.timerInterval floatValue]];[[GCDQueue mainQueue] execute:^{[weakObj.timer start];} afterDelay:NSEC_PER_SEC * [self.timerInterval floatValue]];}else{NSLog(@"请配置参数,亲:)");}
}@end

主函数中使用的源码:

RootViewController.m

//
//  RootViewController.m
//  PageView
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//#import "RootViewController.h"
#import "YXGCD.h"
#import "UIScrollView+YX.h"@interface RootViewController ()<UIScrollViewDelegate>@property (nonatomic, strong) GCDTimer  *timer;@property (nonatomic, assign) NSInteger  currentPage;
@property (nonatomic, assign) NSInteger  largestPage;@end@implementation RootViewController- (void)viewDidLoad
{[super viewDidLoad];self.view.backgroundColor = [UIColor blackColor];// 数据源NSArray *array = @[@"YouXianMing", @"QiuLiang", @"LinKen", @"KeLinDun"];// 初始化UIScrollViewUIScrollView *rootView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 320)];rootView.pagingEnabled = YES;rootView.contentSize   = CGSizeMake(320*array.count, 320);[self.view addSubview:rootView];// 根据数据源加载控件[array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {UILabel *tmp          = [[UILabel alloc] initWithFrame:CGRectMake(idx*320, 0, 320, 320)];tmp.text              = obj;tmp.layer.borderWidth = 2.f;tmp.textColor         = [UIColor cyanColor];tmp.font              = [UIFont fontWithName:@"HelveticaNeue-Thin" size:30];tmp.textAlignment     = NSTextAlignmentCenter;tmp.backgroundColor   = [UIColor colorWithRed:arc4random()%100/100.fgreen:arc4random()%100/100.fblue:arc4random()%100/100.falpha:0.5f];[rootView addSubview:tmp];}];// 设定参数值后开始轮播rootView.timer         = [[GCDTimer alloc] initInQueue:[GCDQueue mainQueue]];rootView.currentPage   = [NSNumber numberWithInt:0];rootView.largestPage   = [NSNumber numberWithInt:array.count];rootView.timerInterval = [NSNumber numberWithInt:4];[rootView start];
}@end

以下来详细讲解下设计的思路:

定时器是用来实现轮播用定时器,这个是最起码的条件:)

runtime添加属性请自行百度脑补或者找笔者之前的教程文章:)

start方法实现的一些细节需要注意:

以下是设计的最为核心的地方: