ReactiveCocoa: View doesn't update when ViewModel property changes

Question

I cannot understand, why my View doesn't update after ViewModel changes.

I have binded my button properties in View:

- (void)bindViewModel
{
    // ViewModel -> View
    RAC(self.nextButton, backgroundColor)   = RACObserve(self.viewModel, nextButtonColor);
    RAC(self.nextButton, enabled)           = RACObserve(self.viewModel, nextButtonEnabled);
}

This is my ViewModel:

@implementation REBaseAuthViewModel


- (instancetype)init
{
    self = [super init];

    if ( self ) {

        RACSignal *inputValidSignal = [RACObserve(self, textFieldText)
                                       map:^id(NSString *text) {

                                           BOOL b = [self validateInput:text];
                                           NSLog(@"Input is valid: %d", b);
                                           return @(b);

                                       }];
        RACSignal *inProressSignal = RACObserve(self, inProress);


        RAC(self, nextButtonEnabled) = [[inputValidSignal
                                         combineLatestWith:[inProressSignal not]]
                                        and];
    }

    return self;
}


- (BOOL)validateInput:(NSString *)text
{
    return text.length > 0;
}


- (void)setNextButtonEnabled:(BOOL)nextButtonEnabled
{
    _nextButtonEnabled = nextButtonEnabled;

    NSLog(@"nextButtonEnabled: %d", nextButtonEnabled);

    self.nextButtonColor = nextButtonEnabled ? [UIColor primaryBlueColor] : [UIColor inactiveButtonColor];
}


@end

Log shows that nextButtonEnabled is changing correctly in ViewModel. But View doesn't change.

Answer 1

发现错误。我的viewModel是零。

我从另一个继承我的控制器。我在ViewModel中初始化ViewDidLoad，bindViewModel之后调用bindViewModel。因为ViewDidLoad在父控制器的viewModel中被调用。

现在我在initWithCoder中初始化ViewDidLoad，而不是- (instancetype)initWithCoder:(NSCoder *)aDecoder { self = [super initWithCoder:aDecoder]; if ( self ) { self.viewModel = [[REPhoneViewModel alloc] init]; } return self; } /*- (void)viewDidLoad { [super viewDidLoad]; self.viewModel = [[REPhoneViewModel alloc] init]; }*/ ：

SELECT *
FROM [EMAIL].[dbo].[T_client]
JOIN [EMAIL].[dbo].[T_promo_code] ON 
(INDEX([EMAIL].[dbo].[T_client].idx_client)) = (INDEX ([EMAIL].[dbo].[T_promo_code].idx_code))