Comprehensive strengths of iOS-UIScrollView and UIPageControl, scrolling, carousel, and uiscrollview

Comprehensive strengths of iOS-UIScrollView and UIPageControl, scrolling, carousel, and uiscrollview
This code mainly implements switching between images

 

Directory structure

 

Code

ViewController. m file

# Import "ViewController. h "@ interface ViewController () @ property (strong, nonatomic) UIScrollView * scrollView; @ property (strong, nonatomic) UIPageControl * pageControl; // Store Image @ property (strong, nonatomic) UIImageView * firstIamges; @ property (strong, nonatomic) UIImageView * secondImage; @ property (strong, nonatomic) UIImageView * thirdImage; // a set of stored images @ property (strong, nonatomic) NSMutableArray * imageArray; // the current page number @ property (assign, nonatomic) int currentPage; @ end @ implementation ViewController-(void) viewDidLoad {[super viewDidLoad]; self. scrollView = [[UIScrollView alloc] initWithFrame: CGRectMake (0, 20, WIDTH, HEIGHT)]; self. scrollView. contentSize = CGSizeMake (WIDTH * 3, 0); self. scrollView. pagingEnabled = YES; self. scrollView. delegate = self; self. scrollView. showsHorizontalScrollIndicator = NO; [self. view addSubview: self. scrollView]; self. pageControl = [[UIPageControl alloc] initWithFrame: CGRectMake (WIDTH/2.7, 300, WIDTH/5, 20)]; // set the current page self. pageControl. currentPage = 0; // page self. pageControl. numberOfPages = 5; // specify the page color self. pageControl. currentPageIndicatorTintColor = [UIColor redColor]; self. pageControl. pageIndicatorTintColor = [UIColor blueColor]; [self. view addSubview: self. pageControl]; // initialize the set of stored images self. imageArray = [NSMutableArray array]; for (int I = 1; I <6; I ++) {UIImage * image = [UIImage imageNamed: [NSString stringWithFormat: @ "% d", I]; [self. imageArray addObject: image];} self. firstIamges = [[UIImageView alloc] init]; self. secondImage = [[UIImageView alloc] init]; self. thirdImage = [[UIImageView alloc] init]; // the current page number self. currentPage = 0; [self reloadImage];}-(void) reloadImage {// first case, first page if (self. currentPage = 0) {self. firstIamges. image = [self. imageArray lastObject]; self. secondImage. image = [self. imageArray objectAtIndex: self. currentPage]; self. thirdImage. image = [self. imageArray objectAtIndex: self. currentPage + 1];} // The last page of else if (self. currentPage = self. imageArray. count-1) {self. firstIamges. image = [self. imageArray objectAtIndex: self. currentPage-1]; self. secondImage. image = [self. imageArray objectAtIndex: self. currentPage]; self. thirdImage. image = [self. imageArray objectAtIndex: 0];} // intermediate page else {self. firstIamges. image = [self. imageArray objectAtIndex: self. currentPage-1]; self. secondImage. image = [self. imageArray objectAtIndex: self. currentPage]; self. thirdImage. image = [self. imageArray objectAtIndex: self. currentPage + 1];} self. firstIamges. frame = CGRectMake (0, 0, WIDTH, 300); self. secondImage. frame = CGRectMake (WIDTH, 0, WIDTH, 300); self. thirdImage. frame = CGRectMake (WIDTH * 2, 0, WIDTH, 300); [self. scrollView addSubview: self. firstIamges]; [self. scrollView addSubview: self. secondImage]; [self. scrollView addSubview: self. thirdImage]; self. scrollView. contentOffset = CGPointMake (WIDTH, 0) ;}# pragma mark-Scrollview Delegate // change the chart in the rolling end state-(void) scrollViewDidEndDecelerating :( UIScrollView *) scrollView {float x = self. scrollView. contentOffset. x; // left if (x <0 | x = 0) {if (self. currentPage = 0) {self. currentPage = (int) self. imageArray. count-1;} else {self. currentPage --;} // to the right if (x> WIDTH * 2 | x = WIDTH * 2) {if (self. currentPage = (int) self. imageArray. count-1) {self. currentPage = 0;} else {self. currentPage ++;} self. pageControl. currentPage = self. currentPage; [self reloadImage];}-(void) didReceiveMemoryWarning {[super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated .} @ end

ViewController. h file

#import <UIKit/UIKit.h>#define WIDTH self.view.frame.size.width#define HEIGHT self.view.frame.size.height@interface ViewController : UIViewController<UIScrollViewDelegate>@end