iOS 利用UISCrollView作广告自动轮播效果

NSTimer 使用的好处就是当你在滑动如tableview界面是它任然可以实时轮播，

但是如果是开启一个后台线程让它轮播时，活动如tableview时，它就会暂停轮播

在日常开发中，我们很多的应用都需要用到轮播的效果，有可能是广告也有可能是软件的介绍等等都非常常用，下面我们利用纯代码写一个简单的轮播效果。

首先我们来看一下最后的效果图：

从图片看我们知道，其实这个效果只用了三个控件，第一个当然是我们的UISCrollView，第二个是pagecontrol小点，最后是UIImageView或者uibutton,我们所要做的是把UISCrollView和pageControl加入到当前vc中，然后把图片加入到UISCrollView中进行相关设置就行了，当然要自动轮播定时器是少不了的，下面看看代码：

1.添加我们的控件，还有相关设置：

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#pragma mark -创建图片数组- (NSMutableArray *)advsList{ if(_advsList == nil){ _advsList = [NSMutableArray array]; } return _advsList;} #pragma mark -添加控件- (void)addView{ //添加图片 for (int i = 1; i < 5; i++) { [self.advsList addObject:[NSString stringWithFormat:@"%d.jpg",i]]; } self.view.backgroundColor = [UIColor whiteColor]; //添加滑动视图 self.scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 150)]; //设置代理这个必须的 self.scrollView.delegate = self; //设置总大小也就是里面容纳的大小 self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * self.advsList.count,self.scrollView.frame.size.height); [self.scrollView setBackgroundColor:[UIColor blackColor]]; //里面的子视图跟随父视图改变大小 [self.scrollView setAutoresizesSubviews:YES]; //设置分页形式，这个必须设置 [self.scrollView setPagingEnabled:YES]; //隐藏横竖滑动块 [self.scrollView setShowsVerticalScrollIndicator:NO]; [self.scrollView setShowsHorizontalScrollIndicator:NO]; [self.view addSubview:self.scrollView]; //场景UIPageControl显示控件，并修改小点颜色 self.pagePoint = [[UIPageControl alloc]init]; self.pagePoint.currentPageIndicatorTintColor = [UIColor blackColor]; self.pagePoint.pageIndicatorTintColor = [UIColor grayColor]; self.pagePoint.frame = CGRectMake(self.view.frame.size.width - self.pagePoint.bounds.size.width-self.advsList.count*10, self.scrollView.frame.origin.y+135, self.pagePoint.bounds.size.width, self.pagePoint.bounds.size.height); [self.pagePoint setNumberOfPages:[self.advsList count]]; [self.view addSubview:self.pagePoint]; }

这部分其实只要记得把UIPageControl加到当前视图，而不是UIScrollView中然后设置好各自的frame就好了，关于UIPageControl的更多介绍你可以移步到这篇文章中iOS UIPageControl的使用。

2.添加图片到scroview中

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for(int i = 0; i < [self.advsList count]; i ++){ UIButton *thumbView = [[UIButton alloc] init]; [thumbView addTarget:self action:@selector(myDidSelectAdvAtIndex:) forControlEvents:UIControlEventTouchUpInside]; thumbView.tag = i; thumbView.frame = CGRectMake(self.view.frame.size.width * i, 0, self.view.frame.size.width, 150); [thumbView setBackgroundImage:[UIImage imageNamed:self.advsList[i]] forState:UIControlStateNormal]; //去掉高亮效果 thumbView.adjustsImageWhenHighlighted = NO; [self.scrollView addSubview:thumbView]; }

为了方便设置点击事件，我里面添加了UIButton这样打击事件处理也就相应的简单很多了。

3.UIScroView代理事件，求出当前的页数及滑动指定位置，以便设置我们的UIPageControl小圆点的位置

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#pragma mark -滑动的距离- (void)scrollToIndex:(NSInteger)index{ CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * index; frame.origin.y = 0; [self.scrollView scrollRectToVisible:frame animated:YES];} #pragma mark -滑动完成时计算滑动到第几页- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ CGFloat pageWidth = scrollView.frame.size.width; int page = floor((scrollView.contentOffset.x - pageWidth / 2) /pageWidth) +1; [self.pagePoint setCurrentPage:page];}

4.添加一个定时器，让广告动起来

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#pragma mark -添加定时器 -(void)addNSTimer { NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(nextPage) userInfo:nil repeats:YES]; //添加到runloop中 [[NSRunLoop mainRunLoop]addTimer:timer forMode:NSRunLoopCommonModes]; _timer = timer; } #pragma mark -删除定时器 -(void)removeNSTimer { [ _timer invalidate]; _timer =nil; }

5.还有一个重要的一点是，我们手动滑动的时候你必须停止定时器，当手指离开时重新启动，这两个方法都是UIScroView的代理方法：

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#pragma mark -当用户开始拖拽的时候就调用移除计时器-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{ [self removeNSTimer];}#pragma mark -当用户停止拖拽的时候调用添加定时器-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ [self addNSTimer];}

好了 一个简单的自动轮播广告已经做好了。如果你懒得自己写代码的话，下面是整个小demo的代码，其实只是一个.m文件而已Objective-C

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// // AdViewController.m // test // // Created by GuoMS on 14-10-2. // Copyright (c) 2014年 GuoMs. All rights reserved. // #import "AdViewController.h" @interface AdViewController ()<UIScrollViewDelegate> { NSTimer *_timer; BOOL isAdd; } @end @implementation AdViewController - (void)viewDidLoad { [super viewDidLoad]; #ifdef __IPHONE_7_0 if ([[UIDevice currentDevice].systemVersion floatValue] >= 7.0) { self.edgesForExtendedLayout = UIRectEdgeNone; } #endif [self addView]; [self showAdvs]; [self addNSTimer]; } #pragma mark -创建图片数组 - (NSMutableArray *)advsList { if(_advsList == nil){ _advsList = [NSMutableArray array]; } return _advsList; } #pragma mark -添加控件 - (void)addView{ //添加图片 for (int i = 1; i < 5; i++) { [self.advsList addObject:[NSString stringWithFormat:@"%d.jpg",i]]; } self.view.backgroundColor = [UIColor whiteColor]; //添加滑动视图 self.scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 150)]; //设置代理这个必须的 self.scrollView.delegate = self; //设置总大小也就是里面容纳的大小 self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * self.advsList.count,self.scrollView.frame.size.height); [self.scrollView setBackgroundColor:[UIColor blackColor]]; //里面的子视图跟随父视图改变大小 [self.scrollView setAutoresizesSubviews:YES]; //设置分页形式，这个必须设置 [self.scrollView setPagingEnabled:YES]; //隐藏横竖滑动块 [self.scrollView setShowsVerticalScrollIndicator:NO]; [self.scrollView setShowsHorizontalScrollIndicator:NO]; [self.view addSubview:self.scrollView]; //场景UIPageControl显示控件，并修改小点颜色 self.pagePoint = [[UIPageControl alloc]init]; self.pagePoint.currentPageIndicatorTintColor = [UIColor blackColor]; self.pagePoint.pageIndicatorTintColor = [UIColor grayColor]; self.pagePoint.frame = CGRectMake(self.view.frame.size.width - self.pagePoint.bounds.size.width-self.advsList.count*10, self.scrollView.frame.origin.y+135, self.pagePoint.bounds.size.width, self.pagePoint.bounds.size.height); [self.pagePoint setNumberOfPages:[self.advsList count]]; [self.view addSubview:self.pagePoint]; } #pragma mark -展示广告位,初始化 -(void)showAdvs{ isAdd = true; for (UIView *view in [self.scrollView subviews]){ [view removeFromSuperview]; } for(int i = 0; i < [self.advsList count]; i ++){ UIButton *thumbView = [[UIButton alloc] init]; [thumbView addTarget:self action:@selector(myDidSelectAdvAtIndex:) forControlEvents:UIControlEventTouchUpInside]; thumbView.tag = i; thumbView.frame = CGRectMake(self.view.frame.size.width * i, 0, self.view.frame.size.width, 150); [thumbView setBackgroundImage:[UIImage imageNamed:self.advsList[i]] forState:UIControlStateNormal]; thumbView.adjustsImageWhenHighlighted = NO; [self.scrollView addSubview:thumbView]; } } #pragma mark -添加定时器 -(void)addNSTimer { NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(nextPage) userInfo:nil repeats:YES]; //添加到runloop中 [[NSRunLoop mainRunLoop]addTimer:timer forMode:NSRunLoopCommonModes]; _timer = timer; } #pragma mark -删除定时器 -(void)removeNSTimer { [ _timer invalidate]; _timer =nil; } #pragma mark -定时器下一页 - (void)nextPage{ int num = self.pagePoint.currentPage; if(isAdd){ num++; if(num == self.advsList.count -1){ isAdd = false; } }else{ num--; if(num == 0){ isAdd = true; } } [self scrollToIndex:num]; } #pragma mark -滑动的距离 - (void)scrollToIndex:(NSInteger)index { CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * index; frame.origin.y = 0; [self.scrollView scrollRectToVisible:frame animated:YES]; } #pragma mark -滑动完成时计算滑动到第几页 - (void)scrollViewDidScroll:(UIScrollView *)scrollView { CGFloat pageWidth = scrollView.frame.size.width; int page = floor((scrollView.contentOffset.x - pageWidth / 2) /pageWidth) +1; [self.pagePoint setCurrentPage:page]; } #pragma mark -当用户开始拖拽的时候就调用移除计时器 -(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView { [self removeNSTimer]; } #pragma mark -当用户停止拖拽的时候调用添加定时器 -(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate { [self addNSTimer]; } #pragma mark -点击广告 - (void)myDidSelectAdvAtIndex:(id) index { UIButton *thumbView = (UIButton *)index; NSLog(@"你点击了第个%d广告",thumbView.tag); } @end