在Swift中包含的外观 [英] appearanceWhenContainedIn in Swift

问题描述

我正在尝试将我的应用转换为Swift语言。

I'm trying to convert my app to the Swift language.

我有这行代码：

[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil]
                     setTitleTextAttributes:textDictionary
                                   forState:UIControlStateNormal];

如何将其转换为Swift？

How to convert it to Swift?

在 Apple的文档中，没有这样的方法。

推荐答案

iOS 9更新：

如果您的目标是iOS 9+（从Xcode 7 b1开始）， UIAppearance 协议中有一种新方法，它不使用varargs：

Update for iOS 9:

If you're targeting iOS 9+ (as of Xcode 7 b1), there is a new method in the UIAppearance protocol which does not use varargs:

static func appearanceWhenContainedInInstancesOfClasses(containerTypes: [AnyObject.Type]) -> Self

可以这样使用：

UITextField.appearanceWhenContainedInInstancesOfClasses([MyViewController.self]).keyboardAppearance = .Light

如果你仍然需要支持iOS 8或更早版本，请使用以下原始答案来解决这个问题。

If you still need to support iOS 8 or earlier, use the following original answer to this question.

这些方法不适用于Swift，因为Obj-C varargs方法与Swift不兼容（参见 http://www.openradar.me/17302764 。

These methods are not available to Swift because Obj-C varargs methods are not compatible with Swift (see http://www.openradar.me/17302764).

我写了一个非可变的解决方法，可以在Swift中工作（我重复 UIBarItem 的相同方法，该方法不是从 UIView 下降的：

I wrote a non-variadic workaround which works in Swift (I repeated the same method for UIBarItem, which doesn't descend from UIView):

// UIAppearance+Swift.h
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface UIView (UIViewAppearance_Swift)
// appearanceWhenContainedIn: is not available in Swift. This fixes that.
+ (instancetype)my_appearanceWhenContainedIn:(Class<UIAppearanceContainer>)containerClass;
@end
NS_ASSUME_NONNULL_END

-

// UIAppearance+Swift.m
#import "UIAppearance+Swift.h"
@implementation UIView (UIViewAppearance_Swift)
+ (instancetype)my_appearanceWhenContainedIn:(Class<UIAppearanceContainer>)containerClass {
    return [self appearanceWhenContainedIn:containerClass, nil];
}
@end

请务必在您的桥接标题中#importUIAppearance + Swift.h。

然后，从Swift调用（例如）：

Then, to call from Swift (for example):

# Swift 2.x:
UITextField.my_appearanceWhenContainedIn(MyViewController.self).keyboardAppearance = .Light

# Swift 3.x:
UITextField.my_appearanceWhenContained(in: MyViewController.self).keyboardAppearance = .light

这篇关于在Swift中包含的外观的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！