iOS基于UIScrollView实现滑动引导页

#import <UIKit/UIKit.h>  @interface WelcomeViewController : UIViewController  @end 

#import "WelcomeViewController.h" #define IMAGECOUNT 3  @interface WelcomeViewController () <UIScrollViewDelegate> @property (nonatomic, strong)UIPageControl *pageControl;  @end  @implementation WelcomeViewController  - (void)viewDidLoad {   [super viewDidLoad];   //创建ScrollView   UIScrollView *sv = [[UIScrollView alloc] init];   sv.frame = self.view.bounds;   //设置边缘不弹跳   sv.bounces = NO;   //整页滚动   sv.pagingEnabled = YES;   sv.showsHorizontalScrollIndicator = NO;      //加入多个子视图(ImageView)   for(NSInteger i=0; i<IMAGECOUNT; i++){     NSString *imgName = [NSString stringWithFormat:@"%ld", i+1];     UIImage *image = [UIImage imageNamed:imgName];     UIImageView *imageView = [[UIImageView alloc]initWithImage:image];     CGRect frame = CGRectZero;     frame.origin.x = i * sv.frame.size.width;     frame.size = sv.frame.size;     imageView.frame = frame;     [sv addSubview:imageView];          if(i==IMAGECOUNT-1){       //开启图片的用户点击功能       imageView.userInteractionEnabled = YES;       //加个按钮       UIButton *button = [[UIButton alloc]init];              button.frame = CGRectMake((imageView.frame.size.width-150)/2, imageView.frame.size.height*0.8, 150, 40);       button.backgroundColor = [UIColor orangeColor];       [button setTitle:@"立即体验" forState:UIControlStateNormal];       button.titleLabel.font = [UIFont boldSystemFontOfSize:16];       [imageView addSubview:button];       [button addTarget:self action:@selector(enter) forControlEvents:UIControlEventTouchUpInside];    }   }      sv.contentSize = CGSizeMake(IMAGECOUNT * sv.frame.size.width, sv.frame.size.height);      [self.view addSubview:sv];      //加入页面指示控件PageControl   UIPageControl *pageControl = [[UIPageControl alloc]init];   self.pageControl = pageControl;   //设置frame   pageControl.frame = CGRectMake(0, self.view.frame.size.height - 40, self.view.frame.size.width, 20);   //分页面的数量   pageControl.numberOfPages = IMAGECOUNT;   //设置小圆点渲染颜色   pageControl.pageIndicatorTintColor = [UIColor whiteColor];   //设置当前选中小圆点的渲染颜色   pageControl.currentPageIndicatorTintColor = [UIColor redColor];   //关闭用户点击交互   pageControl.userInteractionEnabled = NO;      [self.view addSubview:pageControl];      sv.delegate = self;       } - (void)enter {   NSLog(@"进入应用"); }  //UIScrollViewDelegate方法 - (void)scrollViewDidScroll:(UIScrollView *)scrollView {   CGPoint offset = scrollView.contentOffset;   if(offset.x<=0){     offset.x = 0;     scrollView.contentOffset = offset;   }   NSUInteger index = round(offset.x / scrollView.frame.size.width);   self.pageControl.currentPage = index; }  - (void)didReceiveMemoryWarning {   [super didReceiveMemoryWarning];   // Dispose of any resources that can be recreated. }   @end