设置引导页（第一次登陆进入引导页）

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

#import "AppDelegate.h"
#import "GuideViewController.h"
#import "RootViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    // 判断是否是第一次登陆
    if (![[NSUserDefaults standardUserDefaults] objectForKey:@"FirstLaunch"]) {
        [[NSUserDefaults standardUserDefaults] setObject:@(true) forKey:@"FirstLaunch"];
        self.window.rootViewController = [[GuideViewController alloc] init];
    }else{
        self.window.rootViewController = [[RootViewController alloc] init];
    }

    [self.window makeKeyAndVisible];
    return YES;
}
@end

#import <UIKit/UIKit.h>

@interface GuideViewController : UIViewController

@end

#import "GuideViewController.h"
#import "RootViewController.h"

@interface GuideViewController ()

@end

@implementation GuideViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // 初始化scrollView
    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // 隐藏水平滚动条
    scrollView.showsHorizontalScrollIndicator = NO;
    // 翻页效果
    scrollView.pagingEnabled = YES;
    // 设置scrollView的内容窗口大小
    scrollView.contentSize = CGSizeMake([UIScreen mainScreen].bounds.size.width * 3, [UIScreen mainScreen].bounds.size.height);
    [self.view addSubview:scrollView];
    // 设置滚动图片
    NSArray *array = [[NSArray alloc] initWithObjects:@"1-1.jpg",@"1-2.jpg",@"1-3.jpg", nil];
    for (int i = 0; i < array.count; i++) {
        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:array[i]]];
        imageView.frame = CGRectMake([UIScreen mainScreen].bounds.size.width * i, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
        [scrollView addSubview:imageView];
        imageView.tag = 1000 + i;
    }
    // 获取最后一个imageView，然后在其上面加button
    UIImageView *imgView = [self.view viewWithTag:1002];
    // 父视图要可操作，否则其上面的子视图（button）不可操作
    imgView.userInteractionEnabled = YES;
    // 设置button
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = CGRectMake(([UIScreen mainScreen].bounds.size.width - 150)/2.0, [UIScreen mainScreen].bounds.size.height - 120, 150, 80);
    [btn setBackgroundColor:[UIColor clearColor]];
    [btn setTitle:@"马上体验" forState:0];
    [btn setTitleColor:[UIColor redColor] forState:0];
    [btn addTarget:self action:@selector(comeToRootController:) forControlEvents:UIControlEventTouchUpInside];
    [imgView addSubview:btn];
}

- (void)comeToRootController:(UIButton *)sender{

    RootViewController *root = [[RootViewController alloc] init];
    UIApplication *app = [UIApplication sharedApplication];
    app.keyWindow.rootViewController = root;
}

@end

#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end

#import "RootViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor orangeColor];
}

@end