CODEWITHSUNDEEP
iosreactive-cocoa
MeloS
MeloS

Reputation: 7938

ReactiveCocoa: How do you bind a button's title to a text property?

I've got a UIButton whose title for state normal/highlighted should keep synced with a property of its container object.

How can I bind button title for specific state with a string property?

Edit:

I know that using RACObserve and change the button title in subcribeNext block is a solution.
I'm looking for something more specifically designed for UIButton like:

RACBindButtonTitle(button, property, state1, state2);

I don't know if there is some "RAC sugar" like this.

Upvotes: 2

Views: 1605

Answers (3)

Xaree Lee
Xaree Lee

Reputation: 3387

Please refer to this gist.

You can't use RAC() directly on a UIButton because of the UIKit design:

RAC(self.button.titleLabel, text) = titleSignal;  // Don't do this.

One of the solutions is using dynamic property to support RAC() binding macro:

// .h
@interface UIButton (RACTitleSupport)
@property (strong, nonatomic) NSString *racExt_Title;
@end

// .m
@implementation UIButton (RACTitleSupport)
@dynamic racExt_Title;
- (void)setRacExt_Title:(NSString *)racExt_Title
{
  [self setTitle:racExt_Title forState:UIControlStateNormal];
}
- (NSString *)racExt_Title
{
  return [self titleForState:UIControlStateNormal];
}
@end

Now you can use RAC() binding macro like this:

RAC(self, button.racExt_Title) = titleSignal;

Cheers <3

Upvotes: 0

Charles Maria
Charles Maria

Reputation: 2195

Here's a way to do it without explicit subscription. Explicit subscription should be avoided whenever possible so that you don't have to go through the whole @weakify(self) @strongify(self) dance.

[self.button rac_liftSelector:@selector(setTitle:forState:)
                withSignals:
                            RACObserve(self, normalButtonTitle),
                            [RACSignal return:@(UIControlStateNormal)],
                            nil];
[self.button rac_liftSelector:@selector(setTitle:forState:)
                withSignals:
                            RACObserve(self, selectedButtonTitle),
                            [RACSignal return:@(UIControlStateSelected)],
                            nil];

liftSelector:withSignals: will subscribe eagerly to its signals, unlike many another RAC functions.

Upvotes: 6

Allen Hsu
Allen Hsu

Reputation: 3534

If you mean they're synced with one property, something like this:

[RACAble(self.buttonTitle) subscribeNext:^(NSString *newTitle) {
    NSString *normalTitle = [NSString stringWithFormat:@"Normal %@", newTitle];
    NSString *highlightedTitle = [NSString stringWithFormat:@"Highlighted %@", newTitle];
    [self.button setTitle:normalTitle forState:UIControlStateNormal];
    [self.button setTitle:highlightedTitle forState:UIControlStateHighlighted];
}];

If you mean there're two properties, something like this:

[RACAble(self.normalButtonTitle) subscribeNext:^(NSString *newTitle) {
    [self.button setTitle:newTitle forState:UIControlStateNormal];
}];

[RACAble(self.highlightedButtonTitle) subscribeNext:^(NSString *newTitle) {
    [self.button setTitle:newTitle forState:UIControlStateHighlighted];
}];

Upvotes: 1

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