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 
     
      #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 
     
      #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, &currentPageFlag,                             nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);    objc_setAssociatedObject(self, &currentPageFlag,                             currentPage,                             OBJC_ASSOCIATION_RETAIN_NONATOMIC);}- (NSNumber *)currentPage{    return objc_getAssociatedObject(self, &currentPageFlag);}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 ()
     
      @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UIScrollView    UIScrollView *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.f                                                green:arc4random()%100/100.f                                                 blue:arc4random()%100/100.f                                                alpha: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: