ios 学习 广告图片轮播器

 //
 //  ViewController.m
 //  图片轮播器
 //
 //  Created by zjj on 15/5/23.
 //  Copyright (c) 2015年 zjj. All rights reserved.
 //

 #import "ViewController.h"
 #define kCount 5
 @interface ViewController () <UIScrollViewDelegate>
 @property (nonatomic,strong)UIScrollView *scroView;
 @property (nonatomic,strong)UIPageControl *pageControl;
 @property (nonatomic,strong)NSTimer *time;
 @end

 @implementation ViewController
 /**
  开发思路
  1>创建scrollView
  2>用UIimageView加载图片 并修改图片的x值
  3>创建分页控件UIpageControl
  4>绑定分页圆点点 点击圆点点换下一页
  5>绑定时钟
  */
 #pragma mark 初始化scrollView
 - (UIScrollView *)scroView
 {
     if (_scroView == nil) {
         _scroView = [[UIScrollView alloc]initWithFrame:CGRectMake(, , , )];
         _scroView.backgroundColor = [UIColor blueColor];
         [self.view addSubview:_scroView];
         _scroView.bounces = NO;
         _scroView.showsHorizontalScrollIndicator = NO;
         _scroView.showsVerticalScrollIndicator = NO;
         _scroView.contentSize = CGSizeMake(_scroView.bounds.size.width * kCount, );
         self.scroView.pagingEnabled = YES;
         _scroView.delegate = self;
     }
     return _scroView ;
 }
 #pragma mark 初始化PageCOntrol
 - (UIPageControl *)pageControl
 {
     if (_pageControl == nil) {
         // 分页控件 跟scrollView 是独立的
         _pageControl = [[UIPageControl alloc]init];
         _pageControl.numberOfPages = kCount;
         CGSize size = [_pageControl sizeForNumberOfPages:kCount];
         _pageControl.bounds = CGRectMake(, , size.width, size.height);
         _pageControl.center = CGPointMake(self.scroView.center.x, self.scroView.center.y+(self.scroView.center.y/));
         _pageControl.pageIndicatorTintColor = [UIColor redColor];
         _pageControl.currentPageIndicatorTintColor = [UIColor blackColor];
         [self.view addSubview:_pageControl];
         self.pageControl = _pageControl;
     }
     return _pageControl;
 }

 - (void)viewDidLoad {
     [super viewDidLoad];
     for (int i = ; i < kCount; i++) {
        NSString *icon = [NSString stringWithFormat:@"img_%02d",i + ];
         UIImageView *imgView = [[UIImageView alloc]initWithFrame:self.scroView.bounds];
         imgView.image = [UIImage imageNamed:icon];
         [self.scroView addSubview:imgView];
     }
     // 添加事件之后执行该块代码重新赋值x值
     [self.scroView.subviews enumerateObjectsUsingBlock:^(UIImageView *imageView, NSUInteger idx, BOOL *stop) {
         CGRect frame = imageView.frame;
         frame.origin.x = idx * frame.size.width;
         imageView.frame = frame;
     }];
     self.pageControl.currentPage = ;
     [self.pageControl addTarget:self action:@selector(pageChange:) forControlEvents:UIControlEventTouchUpInside];
     [self start];
 }
 #pragma mark 启动时钟
 - (void)start
 {
 //    self.time = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(changeTime) userInfo:nil repeats:YES];// 按住屏幕 画面会停止轮播但 时钟会累积 连跳好几页
     self.time = [NSTimer timerWithTimeInterval:2.0 target:self selector:@selector(changeTime) userInfo:nil repeats:YES];// 按住屏幕时钟 画面仍然不会停止轮播
     [[NSRunLoop currentRunLoop] addTimer:self.time forMode:NSRunLoopCommonModes];// 添加到（运行循环）轮循
 }

 - (void)changeTime
 {
     int page = (self.pageControl.currentPage + ) % kCount;
     self.pageControl.currentPage = page;
     [self pageChange:self.pageControl];
 }

 #pragma mark 对scrollView进行操作 根据图片偏移位置计算页数
 - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
 {
 //    NSLog(@"%@,%f",  NSStringFromCGPoint(_scroView.contentOffset),_scroView.bounds.size.width);//取出scrollview中当前页的x
     int page = _scroView.contentOffset.x / _scroView.bounds.size.width;
     self.pageControl.currentPage = page; //当前页数
 }

 - (void)pageChange :(UIPageControl *)page
 {
     CGFloat x  = page.currentPage * self.scroView.bounds.size.width;
     [self.scroView setContentOffset:CGPointMake(x, )animated:YES];
 }
 #pragma mark 拖动图片时停止时钟
 - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
 {
     [self.time invalidate];
 }
 #pragma mark 松手后再次启动时钟
 - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
 {
     [self start];
 }
 @end