在 Swift 中更改 UITabBarItem 上的 selectedImage

Question

我一直在尝试更改 UITabBar 上的选定图像。我遵循了其他 Whosebug 问题中列出的步骤，但似乎没有任何效果。

我尝试通过用户定义的运行时属性部分设置图像，并尝试将以下内容添加到 AppDelegate.swift：

var tabBarController = self.window!.rootViewController as UITabBarController
let tabItems = tabBarController.tabBar.items as [UITabBarItem]

var selectedImage0 = UIImage(named:"NewsfeedTabSelected")
selectedImage0?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
tabItems[0].selectedImage = selectedImage0

这不会产生任何结果。我做了一个 println(tabItems[0].title) 并输出了正确的标题，所以我知道对 TabBarItem 的引用正在工作。

有什么想法吗？

Answer 1

我在 AppDelegate 上使用类似的方法解决了问题。

var tabBarController = self.window!.rootViewController as UITabBarController
var tabBar = tabBarController.tabBar as UITabBar

var tabBarItem1 = tabBar.items![0] as UITabBarItem
var tabBarItem2 = tabBar.items![1] as UITabBarItem
var tabBarItem3 = tabBar.items![2] as UITabBarItem

tabBarItem1.selectedImage = UIImage(named: "FirstSelectedImage")
tabBarItem2.selectedImage = UIImage(named: "SecondSelectedImage")
tabBarItem3.selectedImage = UIImage(named: "ThirdSelectedImage")

Answer 2

之前的答案并不完全有效。我必须将新 UIImage 的 UIImageRenderingMode 设置为 AlwaysOriginal，这解决了我的情况。

代码如下：

import UIKit

class MainTab: UITabBarController {

override func viewDidLoad() {

    var tabBar = self.tabBar

    var homeSelectImage: UIImage! = UIImage(named: "firstPageSelected")?.imageWithRenderingMode(.AlwaysOriginal)
    var qaSelectImage: UIImage! = UIImage(named: "Q&ASelected")?.imageWithRenderingMode(.AlwaysOriginal)
    var mySelectImage: UIImage! = UIImage(named: "myBagSelected")?.imageWithRenderingMode(.AlwaysOriginal)

    (tabBar.items![0] as! UITabBarItem ).selectedImage = homeSelectImage
    (tabBar.items![1] as! UITabBarItem ).selectedImage = qaSelectImage
    (tabBar.items![2] as! UITabBarItem ).selectedImage = mySelectImage

    tabBar.tintColor = UIColor.greenColor()

}
}

希望对你有用

Answer 3

Subclass/extend tabBarController 并实现这些方法（我知道它是 obj-c 但它应该直接翻译为 swift）：

#import "const.h"
#import "MainTabBarController.h"

@interface MainTabBarController ()

@end

@implementation MainTabBarController

- (NSArray*)tabTitles {
    return @[@"Connection",
             @"Details",
             [[NSUserDefaults standardUserDefaults] objectForKey:@"LastProfileResponse"] ? @"Profile" : @"Login",
             @"Settings"];
}

- (void)viewDidLoad {
    [super viewDidLoad];


    NSArray *imageNames = @[@"connection_tab_",
                            @"details_tab_",
                            @"profile_tab_",
                            @"settings_tab_"
                            ];

    for (int i = 0; i < self.tabBar.items.count; ++i) {
        ((UITabBarItem*)self.tabBar.items[i]).title = self.tabTitles[i];

        ((UITabBarItem*)self.tabBar.items[i]).selectedImage = [UIImage imageNamed:[imageNames[i] stringByAppendingString:@"on"]];

        ((UITabBarItem*)self.tabBar.items[i]).image = [[UIImage imageNamed:[imageNames[i] stringByAppendingString:@"off"]] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    }

    self.tabBar.translucent = false;
    self.tabBar.barTintColor = SLATE_GREEN;
    self.tabBar.tintColor = YELLOW;
    self.delegate = self;

    [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:WHITE,
                                                                                                 NSForegroundColorAttributeName,
                                                                                                 TAB_FONT,
                                                                                                 NSFontAttributeName, nil]
                                             forState:UIControlStateNormal];
    [[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:YELLOW,
                                                                                                 NSForegroundColorAttributeName, nil]
                                             forState:UIControlStateSelected];
}

在 Swift 中更改 UITabBarItem 上的 selectedImage

Changing selectedImage on UITabBarItem in Swift

ios

swift

uitabbaritem