从UITabBarItem垂头丧气?到UITabBarItem仅解包可选；你的意思是使用'！' [英] Downcast from UITabBarItem? to UITabBarItem only unwraps optionals; did you mean to use '!'

问题描述

我的代码在Xcode 6中运行良好.但是，在更新到Xcode 7之后，我收到了将近20个错误和50条警告.这可能是Swift 2中的某些语法更改

My code was working well in Xcode 6. But, after updating to Xcode 7 I got nearly 20 errors and 50 warnings.This might be some syntax change in Swift 2

解决了所有这些问题，但无法解决:从UITabBarItem下调?到UITabBarItem仅解包可选；您是不是要使用'！'

Solved all those but can't figure out this one : Downcast from UITabBarItem? to UITabBarItem only unwraps optionals; did you mean to use '!'

let tabItems = tabBar.items as! [UITabBarItem]  // Error in  this line
    for (index, value) in enumerate(tabItems)
    {
        var imageName = imageNames[index]
        value.image = UIImage(named: imageName)
        value.imageInsets = UIEdgeInsetsMake(5.0, 0, -5.0, 0)
    }

请帮助！ 预先感谢

推荐答案

尝试一下:

if let tabItems = tabBar.items as [UITabBarItem]? {
    for (index, value) in tabItems.enumerate()
    {
        var imageName = imageNames[index]
        value.image = UIImage(named: imageName)
        value.imageInsets = UIEdgeInsetsMake(5.0, 0, -5.0, 0)
    }
}

您看到此错误，因为items现在具有类型[UITabBarItem]?

You see the error because items now have type [UITabBarItem]?

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