iOS UI入门——Objective-C和Swift下UITabBarController的使用

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很多App启动页过后展示的就是选项卡也就是UITabBarController，这里讲的是最简单的选项卡的实现，直接继承自UITabBarController。

Objective-C代码：

#import "MainTabBarViewController.h"
#import "HomeViewController.h"
#import "UserCenterViewController.h"

@interface MainTabBarViewController ()

@end

@implementation MainTabBarViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor whiteColor];
    [self setupControllers];
    [self setupItems];
}

-(void)setupControllers{
    UINavigationController * nc1 = [[UINavigationController alloc] initWithRootViewController:[[HomeViewController alloc] init]];
    UINavigationController * nc2 = [[UINavigationController alloc] initWithRootViewController:[[UserCenterViewController alloc] init]];
    self.viewControllers = @[nc1,nc2];
}

-(void)setupItems{
    NSArray *titleArray = @[@"首页",@"个人中心"];

    NSArray *selectImageName =@[@"tabbar_home_selected",@"tabbar_mine_selected"];

    NSArray *unselectImageName =@[@"tabbar_home",@"tabbar_mine"];

    for (int i =0; i < titleArray.count; i++) {

        //需要对图片进行单独处理,防止在bar上显示为阴影而不是图片

        UIImage *selectImage = [UIImage imageNamed:selectImageName[i]];

        selectImage = [selectImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

        UIImage *unselectImage = [UIImage imageNamed:unselectImageName[i]];

        unselectImage = [unselectImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

        UITabBarItem *item = self.tabBar.items[i];

        item.selectedImage = selectImage;

        item.image = unselectImage;

        item.title = titleArray[i];

    }

    //设置tabbar背景图
    //[self.tabBar setBackgroundImage:[UIImage imageNamed:@"img_tabBar_bg_iOS8.png"]];

    //设置tabbar按钮被选中时字体的颜色
    [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor redColor]}forState:UIControlStateSelected];
    //设置tabbar按钮未被选中时字体的颜色
    [[UITabBarItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor darkGrayColor]}forState:UIControlStateNormal];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

其中MainTabBarViewController继承自UITabBarController，如果项目启动后就显示，在Appdelegate中实现如下代码即可：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window.rootViewController = [[MainTabBarViewController alloc] init];
    return YES;
}

Swift代码：

import UIKit

class MainTabbarViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.view.backgroundColor = UIColor.white
        self.setupControllees()
        self.setupItems()
    }

    func setupControllees() {
        let nc1 = UINavigationController.init(rootViewController: HomeViewController())
        let nc2 = UINavigationController.init(rootViewController: UserCenterViewController())
        self.viewControllers = [nc1,nc2]

    }

    func setupItems() {
        let titleArray = ["首页","个人中心"]
        let selectImageName = ["tabbar_home_selected","tabbar_mine_selected"]
        let unselectImageName = ["tabbar_home","tabbar_mine"]
        for index in 0...titleArray.count-1 {
            //需要对图片进行单独处理,防止在bar上显示为阴影而不是图片
            var selectImage = UIImage.init(named: selectImageName[index])
            selectImage = selectImage?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
            var unselectImage = UIImage.init(named: unselectImageName[index])
            unselectImage = unselectImage?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
            //初始化items
            let item = self.tabBar.items![index]
            item.selectedImage = selectImage
            item.image = unselectImage
            item.title = titleArray[index]
        }

        //设置tabbar背景图
        //self.tabBar.backgroundImage = UIImage.init(named: "")
        //设置tabbar按钮被选中时字体的颜色
        UITabBarItem.appearance().setTitleTextAttributes([NSAttributedStringKey.foregroundColor:UIColor.red], for: UIControlState.selected)
        //设置tabbar按钮未被选中时字体的颜色
        UITabBarItem.appearance().setTitleTextAttributes([NSAttributedStringKey.foregroundColor:UIColor.darkGray], for: UIControlState.normal)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

其中MainTabBarViewController继承自UITabBarController，如果项目启动后就显示，在Appdelegate中实现如下代码即可：

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        self.window?.rootViewController = MainTabbarViewController()
        return true
    }

效果图：