appearanceWhenContainedIn in Swift

Question

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

I have this line of code:

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

How to convert it to Swift?

In Apple's docs, there is no such method.

Answer 1

You should be able to just translate the Objective-C syntax into Swift syntax.

In swift the methods should be declared like this:

func appearanceWhenContainedIn(containerClass : <UIAppearanceContainer>)
func setTitleTextAttributes(_ attributes: NSDictionary!, forState state: UIControlState)

So you can try this:

UIBarButtonItem.appearanceWhenContainedIn(UINavigationBar).setTitleTextAttributes(textDictionary, forState: UIControlStateNormal)

I still have to figure out if this is the clean way to call a class method in Swift though.

Hope this helps,

Answer 2

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

Which can be used like so:

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

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

For iOS 8 & 7:

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

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

Just be sure to #import "UIAppearance+Swift.h" in your bridging header.

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

Answer 3

Swift 4: iOS 9+

UIProgressView.appearance(whenContainedInInstancesOf: [LNPopupBar.self]).tintColor = .red

Answer 4

This can be extended to any class that conforms to the UIAppearance protocol -- not just UIViews. So here's a more generic version:

UIAppearance+Swift.h

#import <UIKit/UIKit.h>

@interface NSObject (UIAppearance_Swift)

+ (instancetype)appearanceWhenContainedWithin:(Class<UIAppearanceContainer>)containerClass;

@end

UIAppearance+Swift.m

#import "UIAppearance+Swift.h"

@implementation NSObject (UIAppearance_Swift)

+ (instancetype)appearanceWhenContainedWithin:(Class<UIAppearanceContainer>)containerClass {
    if ([self conformsToProtocol:@protocol(UIAppearance)]) {
        return [(id<UIAppearance>)self appearanceWhenContainedIn:containerClass, nil];
    }
    return nil;
}

@end

Answer 5

ios 10 swift 3

UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).title = "Kapat"

Answer 6

You can use this:

UIBarButtonItem.appearance().setTitleTextAttributes(textDictionary, forState: UIControlState.Normal)

Edit: appearanceWhenContainedIn was removed in Swift. This answer was for the Beta 5 to change the appearance of the text of all bar buttons.