[转]iPhone开发应用中UIScrollView代码实现循环滚动

iPhone开发应用中循环滚动一个UIScrollView代码实现是本文要介绍的内容，主要是介绍UIScrollView来实现循环滚动的案例，来看详细内容。

//  testScrollViewViewController.m
//  testScrollView
//  Created by cash on 11-7-4.
//  Copyright 2011年 [email protected]. All rights reserved.
#import "testScrollViewViewController.h"
@implementation testScrollViewViewController
@synthesize scrollView, slideImages;
#define WIDTH_OF_SCROLL_PAGE 320
#define HEIGHT_OF_SCROLL_PAGE 460
#define WIDTH_OF_IMAGE 320 #define HEIGHT_OF_IMAGE 460
#define LEFT_EDGE_OFSET 0
- (void)viewDidLoad {
    scrollView = [[UIScrollView alloc] init];
    CGRect scrollFrame;
    scrollFrame.origin.x = 0;
    scrollFrame.origin.y = 0;
    scrollFrame.size.width = WIDTH_OF_SCROLL_PAGE;
    scrollFrame.size.height = HEIGHT_OF_SCROLL_PAGE;
    scrollView = [[UIScrollView alloc] initWithFrame:scrollFrame];
    scrollView.bounces = YES;
    scrollView.pagingEnabled = YES;
    scrollView.delegate = self;
    scrollView.userInteractionEnabled = YES;
    slideImages = [[NSMutableArray alloc] init];
    [slideImages addObject:@"IMG_0116.PNG"];
    [slideImages addObject:@"IMG_0118.PNG"];
    [slideImages addObject:@"IMG_0119.PNG"];
    [slideImages addObject:@"main_bg.png"];
     //add the last image first
     UIImageView *imageView = [[UIImageView alloc]
     initWithImage:[UIImage imageNamed:[slideImages objectAtIndex:([slideImages count]-1)]]]
     imageView.frame = CGRectMake(LEFT_EDGE_OFSET, 0, WIDTH_OF_IMAGE, HEIGHT_OF_IMAGE);
     [scrollView addSubview:imageView];
     [imageView release];
     for (int i = 0;i<[slideImages count];i++) {
            //loop this bit
            UIImageView *imageView = [[UIImageView alloc]
            initWithImage:[UIImage imageNamed:[slideImages objectAtIndex:i]]];
            imageView.frame = CGRectMake((WIDTH_OF_IMAGE * i) + LEFT_EDGE_OFSET + 320, 0, WIDTH_OF_IMAGE, HEIGHT_OF_IMAGE);
            [scrollView addSubview:imageView];
            [imageView release];
      }
       //add the first image at the end
       imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[slideImages objectAtIndex:0]]];
       imageView.frame = CGRectMake((WIDTH_OF_IMAGE * ([slideImages count] + 1)) + LEFT_EDGE_OFSET, 0, WIDTH_OF_IMAGE, HEIGHT_OF_IMAGE);
        [scrollView addSubview:imageView];
        [imageView release];
        [scrollView setContentSize:CGSizeMake(WIDTH_OF_SCROLL_PAGE * ([slideImages count] + 2), HEIGHT_OF_IMAGE)];
         [scrollView setContentOffset:CGPointMake(0, 0)];
         [self.view addSubview:scrollView];
          [self.scrollView scrollRectToVisible:CGRectMake(WIDTH_OF_IMAGE,0,WIDTH_OF_IMAGE,HEIGHT_OF_IMAGE) animated:NO];
          [super viewDidLoad];} - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
      int currentPage = floor((self.scrollView.contentOffset.x - self.scrollView.frame.size.width
 / ([slideImages count]+2)) / self.scrollView.frame.size.width) + 1;
       if (currentPage==0) {
              //go last but 1 page
   [self.scrollView scrollRectToVisible:CGRectMake(WIDTH_OF_IMAGE * [slideImages count],0,WIDTH_OF_IMAGE,HEIGHT_OF_IMAGE) animated:NO];
 } else
 if (currentPage==([slideImages count]+1)) {
 //如果是最后+1,也就是要开始循环的第一个
 [self.scrollView scrollRectToVisible:CGRectMake(WIDTH_OF_IMAGE,0,WIDTH_OF_IMAGE,HEIGHT_OF_IMAGE) animated:NO];
}
}
- (void)didReceiveMemoryWarning {
  // Releases the view if it doesn't have a superview.
  [super didReceiveMemoryWarning];
  // Release any cached data, images, etc that aren't in use.
  }
 - (void)viewDidUnload {
   // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
 }
 - (void)dealloc {
  [scrollView release];
  [slideImages release];
  [super dealloc];
}
@end