UI定制 - UITabBarController：轻扫则切换页面

■ 页面切换

1. 在开发中经常会遇到通过手机屏幕上向左或向右轻轻划动，就可以实现页面切换需求。下面我们就来实现这一功能

// - AppDelegate.m：指定根视图控制器

#import "AppDelegate.h"
#import "TabBarController.h"

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    TabBarController *tbVC = [[TabBarController alloc] init];
    self.window.rootViewController = tbVC;
    return YES;
}

// - TabBarController.m：里面存放 4 个控制器并，实现通过滑动进而切换页面功能

#import "TabBarController.h"
#import "FirstViewController.h"
#import "SecondViewController.h"
#import "ThirdViewController.h"
#import "FourthViewController.h"
@interface TabBarController ()<UITabBarControllerDelegate>// 代理

@end

@implementation TabBarController

- (void)viewDidLoad {
    [super viewDidLoad];

    FirstViewController *firstVC = [[FirstViewController alloc] init];
    firstVC.title = @"微信";
    firstVC.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"微信" image:[UIImage imageNamed:@"mainframe@2x.png"] tag:100] ;
    firstVC.tabBarItem.badgeValue = @"09";
    UINavigationController * navVC1 = [[UINavigationController alloc] initWithRootViewController:firstVC];
    navVC1.navigationBar.translucent = NO;

    
    SecondViewController *secondVC = [[SecondViewController alloc] init];
    secondVC.title = @"指南";
    secondVC.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"指南" image:[UIImage imageNamed:@"discover@2x.png"] tag:101] ;
    UINavigationController * navVC2 = [[UINavigationController alloc] initWithRootViewController:secondVC];
    navVC2.navigationBar.translucent = NO;

    
    ThirdViewController *thirdVC = [[ThirdViewController alloc] init];
    thirdVC.title = @"列表";
    thirdVC.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"列表"image:[UIImage imageNamed:@"more_hl@2x.png"] tag:102];
    UINavigationController * navVC3 = [[UINavigationController alloc] initWithRootViewController:thirdVC];
    navVC3.navigationBar.translucent = NO;

    
    FourthViewController *fourthVC = [[FourthViewController alloc] init];
    fourthVC.title = @"警告";
    fourthVC.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"警告" image:[UIImage imageNamed:@"qr_toolbar_light_up_hl@2x.png"] tag:103];
    UINavigationController * navVC4 = [[UINavigationController alloc] initWithRootViewController:fourthVC];
    navVC4.navigationBar.translucent = NO;

    self.delegate = self;
    self.viewControllers = @[navVC1,navVC2,navVC3,navVC4];
    self.tabBar.tintColor = [UIColor redColor];
    self.tabBar.translucent = NO;

    // 添加手势：滑动
    [self makeSwitchover];

}


- (void)makeSwitchover{

    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(tappedRightButton)];
    [swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];
    [self.view addGestureRecognizer:swipeLeft];

    UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(tappedLeftButton)];
    [swipeRight setDirection:UISwipeGestureRecognizerDirectionRight];
    [self.view addGestureRecognizer:swipeRight];
}

// 右扫
-(void)tappedRightButton{

    NSUInteger selectedIndex = [self selectedIndex];
    NSArray *aryViewController = self.viewControllers;

    if (selectedIndex < aryViewController.count - 1) {
        UIView *fromView = [self.selectedViewController view];
        UIView *toView = [[self.viewControllers objectAtIndex:selectedIndex + 1] view];
        [UIView transitionFromView:fromView toView:toView duration:1.0f options:UIViewAnimationOptionTransitionCrossDissolve completion:^(BOOL finished) {

            if (finished) {

                [self setSelectedIndex:selectedIndex + 1];
            }

        }];
    }
}

// 左扫
-(void)tappedLeftButton{

    NSUInteger selectedIndex = [self selectedIndex];
    if (selectedIndex > 0) {

        UIView *fromView = [self.selectedViewController view];
        UIView *toView = [[self.viewControllers objectAtIndex:selectedIndex - 1] view];
        [UIView transitionFromView:fromView toView:toView duration:1.0f options:UIViewAnimationOptionTransitionCrossDissolve completion:^(BOOL finished) {

            if (finished) {

                [self setSelectedIndex:selectedIndex - 1];
            }

        }];
    }
}

@end

// - FirstViewController.m

#import "FirstViewController.h"
@implementation FirstViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height -self.tabBarController.tabBar.frame.size.height - 64)];
    imageView.image = [UIImage imageNamed:@"微信.jpeg"];
    [self.view addSubview:imageView];
}


@end

// - SecondViewController.m

#import "SecondViewController.h"
@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height -self.tabBarController.tabBar.frame.size.height - 64)];
    imageView.image = [UIImage imageNamed:@"指南.jpeg"];
    [self.view addSubview:imageView];
    
}

@end

// - ThirdViewController.m

#import "ThirdViewController.h"
@implementation ThirdViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height -self.tabBarController.tabBar.frame.size.height - 64)];
    imageView.image = [UIImage imageNamed:@"列表.jpeg"];
    [self.view addSubview:imageView];
}

@end

// - FourthViewController.m

#import "FourthViewController.h"
@implementation FourthViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height -self.tabBarController.tabBar.frame.size.height - 64)];
    imageView.image = [UIImage imageNamed:@"警告.jpeg"];
    [self.view addSubview:imageView];
}

@end

运行效果