UIAppearance not taking effect on UILabels created programmatically

Question

We have extended UILabel to be able to apply standard fonts and colors for all uses of a given label type in our apps. Eg.

@interface UILabelHeadingBold : UILab         


        

Answer 1

@robert.wijas solution works great !

For iOS 7 and upwards I had to update the key since the one he used are deprecated for 7+ :

- (void)setTextAttributes:(NSDictionary *)numberTextAttributes;
{
    UIFont *font = [numberTextAttributes objectForKey:NSFontAttributeName];
    if (font) {
        self.font = font;
    }
    UIColor *textColor = [numberTextAttributes objectForKey:NSForegroundColorAttributeName];
    if (textColor) {
        self.textColor = textColor;
    }
    UIColor *textShadowColor = [numberTextAttributes objectForKey:NSShadowAttributeName];
    if (textShadowColor) {
        self.shadowColor = textShadowColor;
    }
    NSValue *shadowOffsetValue = [numberTextAttributes objectForKey:NSShadowAttributeName];
    if (shadowOffsetValue) {
        UIOffset shadowOffset = [shadowOffsetValue UIOffsetValue];
        self.shadowOffset = CGSizeMake(shadowOffset.horizontal, shadowOffset.vertical);
    }
}

Answer 2

A workaround that I've used is to manually apply the color from the appearance that is set:

let label = UILabel()
label.textColor = UILabel.appearance().textColor

This way you don't need to reference anything new, or explicitly define the color. This also works for context specific coloring:

label.textColor = UILabel.appearance(whenContainedInInstancesOf:[MyView.self]).textColor

Answer 3

From Apple documentation :

To support appearance customization, a class must conform to the UIAppearanceContainer protocol and relevant accessor methods must be marked with UI_APPEARANCE_SELECTOR.

For example in UINavigationBar.h, tintColor is marked with UI_APPEARANCE_SELECTOR

@property(nonatomic,retain) UIColor *tintColor UI_APPEARANCE_SELECTOR;

But in UILabel.h you can see that the textColor and font propertys are not marked with UI_APPEARANCE_SELECTOR but somehow it works when added in Interface Builder (following the documentation it shouldn't work at all).

Answer 4

Simple hack that is working for me with no issues is to create a category with a UIAppearance setter that modifies UILabel properties.

Following UIAppearance conventions I created a method:

- (void)setTextAttributes:(NSDictionary *)numberTextAttributes;
{
    UIFont *font = [numberTextAttributes objectForKey:UITextAttributeFont];
    if (font) {
        self.font = font;
    }
    UIColor *textColor = [numberTextAttributes objectForKey:UITextAttributeTextColor];
    if (textColor) {
        self.textColor = textColor;
    }
    UIColor *textShadowColor = [numberTextAttributes objectForKey:UITextAttributeTextShadowColor];
    if (textShadowColor) {
        self.shadowColor = textShadowColor;
    }
    NSValue *shadowOffsetValue = [numberTextAttributes objectForKey:UITextAttributeTextShadowOffset];
    if (shadowOffsetValue) {
        UIOffset shadowOffset = [shadowOffsetValue UIOffsetValue];
        self.shadowOffset = CGSizeMake(shadowOffset.horizontal, shadowOffset.vertical);
    }
}

In UILabel category:

@interface UILabel (UISS)

- (void)setTextAttributes:(NSDictionary *)numberTextAttributes UI_APPEARANCE_SELECTOR;

@end

I'm still trying to figure out why the original setter does not work.

Answer 5

I was having this exact same issue, but in Swift. A custom UILabel's appearance would work if added from a storyboard, but not if added from code.

Here's a solution I found in Swift that's working for me:

class MyLabel: UILabel { }

extension UILabel {
    @objc dynamic var customFont: UIFont! {
        get { return self.font }
        set { self.font = newValue }
    }

    @objc dynamic var customColor: UIColor! {
        get { return self.textColor }
        set {  self.textColor = newValue }
    }
}

Then add these lines where you configure your app appearance:

MyLabel.appearance().customFont = UIFont.systemFont(ofSize: 20)
MyLabel.appearance().customColor = UIColor.magenta