使用Reactive Cocoa RACSignal启用UIButton [英] Enabling an UIButton using Reactive Cocoa RACSignal

问题描述

我在视图中添加了 UIButton 。我的观点还有三个文本框即。 用户名，密码和 confirmPassword 。根据这些文本框的合法内容，我需要启用 signUp 按钮。

I have a UIButton added to a view. My view also has three text box viz. username, password and confirmPassword. Based on the legitimate content of these text box, I need to enable my signUp button.

这是我的代码段： -

Here is my code snippet :-

    UIButton *signUp = [[UIButton alloc]initWithFrame:CGRectMake(10, 100, 50, 20)];
    signUp.backgroundColor = [UIColor greenColor];

    signUp.enabled = NO ;
    [self.view addSubview:signUp];

    RACSignal *formValid = [RACSignal
    combineLatest:@[
    username.rac_textSignal,
    password.rac_textSignal,
    confirmPassword.rac_textSignal
    ]
    reduce:^(NSString *username, NSString *password, NSString *passwordVerification)        {
    return @([username length] > 0 && [password length] > 8 && [password      isEqual:passwordVerification]);
    }];

    RAC(signUp.enabled) = formValid; //Error is here

在最后一行，我遇到两个错误： -

In the last line, I'm getting two errors:-

1. ARC不允许将'BOOL'（又名'signed char'）隐式转换为'id'


2. 预期标识符

我是Reactive Cocoa的新手。请忽略错误。

I am new to Reactive Cocoa. Please ignore the mistakes.

推荐答案

RAC（）宏需要两个参数至少是目标对象和该对象上的有效密钥路径。

The RAC() macro takes two arguments at a minimum, the object that's the target and a valid keypath on that object.

如下所示：

RAC(signUp, enabled) = formValid;

你传递的是 signUp.enabled ，这是一个单项，恰好是 BOOL ，而不是对象。扩展宏之后，将 BOOL 传递给期望对象参数的方法，因此编译器会抱怨：

You're passing it signUp.enabled, which is a single item, and happens to be a BOOL, not an object. After the macro is expanded, the BOOL is passed to a method that expects an object argument, so the compiler complains:

[[RACSubscriptingAssignmentTrampoline alloc] initWithTarget:signUp.enabled nilValue:<#garbage#>][@keypath(signUp.enabled, nil)]

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