转载请注明出处，原文网址：http://blog.csdn.net/m_changgong/article/details/8209461作者：张燕广
第一次使用某个App时，一般会有欢迎界面，向右滑动屏幕会出现该App的新增功能或功能介绍或使用帮助相关的界面。通过PageControl可以实现该效果。
实现的功能：通过PageControl，实现多视图切换。
关键词：多视图 PageControl UIPageContrller
1、创建一个Empty Application工程，命名为：MultiView-Navigation，如下图
2、选中工程中的Group MultiView-Tab，然后按住CMD（Windows键）+N，新建视图控制器PageControlViewController，如下图
3、依照上步操作，新建视图控制器WelcomeViewController、FeatureListViewController
4、万事俱备，开始编写代码，首先修改AppDelegate，AppDelegate.h如下：
//// AppDelegate.h// MultiView-PageControl//// Created by Zhang Yanguang on 12-11-21.// Copyright (c) 2012年 MyCompanyName. All rights reserved.//#import <UIKit/UIKit.h>#import "PageControlViewController.h"#import "WelcomeViewController.h"@interface AppDelegate : UIResponder <UIApplicationDelegate>@property (strong, nonatomic) UIWindow *window;@property (strong, nonatomic) PageControlViewController *pageControlViewController;@end
AppDelegate.m主要修改didFinishLaunchingWithOptions方法，如下：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; // Override point for customization after application launch. self.pageControlViewController = [[PageControlViewController alloc]initWithNibName:@"PageControlViewController" bundle:nil]; //设置rootViewController self.window.rootViewController = pageControlViewController; self.window.backgroundColor = [UIColor whiteColor]; [self.window makeKeyAndVisible]; return YES;}5、视图控制器WelcomeViewController、FeatureListViewController仅仅修改了源代码文件，设置了一下背景色，如下：@implementation WelcomeViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{ self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization self.view.backgroundColor = [UIColor redColor]; } return self;}@implementation FeatureListViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{ self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization self.view.backgroundColor = [UIColor greenColor]; } return self;}6、主要工作在PageControlViewController中，PageControlViewController.h如下：//// PageControlViewController.h// MultiView-PageControl//// Created by Zhang Yanguang on 12-11-21.// Copyright (c) 2012年 MyCompanyName. All rights reserved.//#import <UIKit/UIKit.h>#import "WelcomeViewController.h"#import "FeatureListViewController.h"@interface PageControlViewController : UIViewController<UIScrollViewDelegate>{ BOOL pageControlUsed;//用于区分是点击PageControll换页还是通过滚动scrollView换页}//添加代码@property (strong, nonatomic) UIPageControl *pageControl;@property (strong, nonatomic) UIScrollView *scrollView;@property (strong, nonatomic) WelcomeViewController *welComeViewController;@property (strong, nonatomic) FeatureListViewController *featureListViewController;-(void)pageControlChanged:(id)sender;@endPageControlViewController.m如下：
//// PageControlViewController.m// MultiView-PageControl//// Created by Zhang Yanguang on 12-11-21.// Copyright (c) 2012年 MyCompanyName. All rights reserved.//#import "PageControlViewController.h"@interface PageControlViewController ()@end@implementation PageControlViewController@synthesize pageControl;@synthesize scrollView;@synthesize welComeViewController;@synthesize featureListViewController;- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{ self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { } return self;}- (void)viewDidLoad{ [super viewDidLoad]; CGRect frame = [UIScreen mainScreen].applicationFrame; int width = frame.size.width; int height = frame.size.height; frame = CGRectMake(0, 0, width, height); //初始化scrollView scrollView = [[UIScrollView alloc]initWithFrame:frame]; scrollView.showsVerticalScrollIndicator = NO; scrollView.showsHorizontalScrollIndicator = YES; scrollView.pagingEnabled = YES; scrollView.contentSize = CGSizeMake(width*2, height);//scrollView内存大小 scrollView.scrollsToTop = NO; //设置代理 scrollView.delegate = self; int pageControlHeight = 50; NSLog(@"width=%d,height=%d",width,height); //初始化pageControl pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(0, height-pageControlHeight, width, pageControlHeight)]; //pageControl设定 pageControl.numberOfPages = 2; //2页 pageControl.currentPage = 0; pageControl.hidesForSinglePage = NO; pageControl.backgroundColor = [UIColor blackColor]; [pageControl addTarget:self action:@selector(pageControlChanged:) forControlEvents:UIControlEventValueChanged]; //初始化welComeViewController、featureListViewController welComeViewController = [[WelcomeViewController alloc]initWithNibName:@"WelcomeViewController" bundle:nil]; featureListViewController = [[FeatureListViewController alloc]initWithNibName:@"FeatureListViewController" bundle:nil]; //设定welComeViewController的位置 frame = scrollView.frame; frame.origin.y = 0; welComeViewController.view.frame = frame; //设定featureListViewController的位置 frame.origin.x = frame.size.width; featureListViewController.view.frame = frame; //将welComeViewController、featureListViewController加入到scrollView中 [scrollView addSubview:welComeViewController.view]; [scrollView addSubview:featureListViewController.view]; //scrollView设置为黑色背景 scrollView.backgroundColor = [UIColor blackColor]; [self.view insertSubview:scrollView atIndex:0]; //将pageControl的atIndex设置为1，pageControl的view在scrollView的view的上层 [self.view insertSubview:pageControl atIndex:1];}- (void)viewDidUnload{ [super viewDidUnload]; // Release any retained subviews of the main view. pageControl = nil; scrollView = nil; welComeViewController = nil; featureListViewController = nil;}- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{ return (interfaceOrientation == UIInterfaceOrientationPortrait);}//点击pageControl上的白色点触发的事件-(void)pageControlChanged:(id)sender{ int page = pageControl.currentPage; NSLog(@"page=%d",page); CGRect frame = scrollView.frame; frame.origin.x = frame.size.width*page; frame.origin.y = 0; [scrollView scrollRectToVisible:frame animated:YES]; pageControlUsed = YES; //用户通过点击Page Control换页时将其设置为YES}#pragma pageControl methods- (void)scrollViewDidScroll:(UIScrollView *)sender{ NSLog(@"scrollViewDidScroll..."); if(pageControlUsed){//如果用户通过点击Page Control换页，则不做处理 return; } CGFloat pageWidth = scrollView.frame.size.width; NSLog(@"pageWidth=%.2f,scrollView.contentOffset.x=%.2f",pageWidth,scrollView.contentOffset.x); NSLog(@"@ %.2f,%2.f",floor(-0.5),floor(-0.6)); //计算滚到哪页 int page = floor((scrollView.contentOffset.x-pageWidth/2)/pageWidth)+1; pageControl.currentPage = page;}- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{ pageControlUsed = NO;//滚动结束后将pageControlUsed重置为NO}@endUIPageControl由一系列小圆点组成，每个点代表一页，白色的点代表当前选中的页。其实现多视图的原理是scrollView的宽度为WelcomeViewController、FeatureListViewController中View的宽度之和，并且WelcomeViewController、FeatureListViewController的View都是作为scrollView的子视图。当第一页被选中时显示WelcomeViewController的view，但是第二页被选中时显示FeatureListViewController的view。
7、编译、运行，效果如下：
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