objective-c - "Combine latest"与 ReactiveCocoa 和信号的信号

Question

在 ReactiveCocoa 中对信号的信号实现“最新组合”的最佳方法是什么？我有以下问题:

给定 N 个文本字段，订阅 UIControlEditingEventChanged 事件，并根据调用的值创建一个新信号。每个订阅者进行一次订阅，然后将这些值相互结合使用。所以这就是我得到的:

__block NSMutableSet *subscriptions = [NSMutableSet set];
RACSignal *validationSignals = [[[[TEXT_FIELDS rac_sequence].signal flattenMap:^RACStream* (UITextField *textField) {
    return [textField rac_signalForControlEvents:UIControlEventEditingChanged];
}] flattenMap:^RACStream *(UITextField* textField) {
    if(![subscriptions containsObject:textField]) {
         [subscriptions addObject:textField];
        return [textField rac_validationSignal];
    }
    return [RACSignal empty];
}]];

rac_validationSignal 是我自己的 UITextFields 处理验证类。信号正确通过，但一次只有一个。我需要一次获得所有订阅的值，以便获得所有已编辑字段的有效性。

编辑:

一个可能的解决方案涉及一个可变数组，我将新字段添加到该数组并像往常一样发送组合信号。这看起来不错，还有其他想法吗？

__block NSMutableSet *subscriptions = [NSMutableSet set];
__block NSMutableArray *signals = [NSMutableArray array];
RAC(self.editButton, enabled) =
[[[[TEXT_FIELDS rac_sequence].signal flattenMap:^RACStream* (UITextField *textField) {
    return [textField rac_signalForControlEvents:UIControlEventEditingChanged];
}] flattenMap:^RACStream *(UITextField* textField) {
    if(![subscriptions containsObject:textField]) {
        [subscriptions addObject:textField];
        [signals addObject:[textField rac_validationSignal]];
        return [RACSignal combineLatest:signals];
    }
    return [RACSignal empty];
}] map:^NSNumber *(RACTuple *value) {
    for(NSNumber *isValid in value) {
        if(![isValid boolValue]) { return @(NO); }
    }
return @(YES);
}];

谢谢!

Answer 1

你可以试试这个:

NSArray *TEXT_FIELDS = @[[txt1.rac_textSignal distinctUntilChanged],[txt2.rac_textSignal distinctUntilChanged]];
[[RACSignal combineLastest:TEXT_FIELDS reduce:^ (NSSTring *txt1, NSString *txt2) {
    // Return your validate method here
    // Signal only send `next` value it is different from previous `next` value 
    return [self inputvalication];
}] setKeyPath:@"enabled" onObject:self.myButton];