Swift3.0：不能调用非功能类型的值'（（Selector！）-> Bool）！'

Question

I have to migrate my swift 2.x code to Swift 3.0. In this case, I found an issue "Can not call value of non-functional type ((Selector!)-> Bool)!". I googled but not found any good solution which solved my problem.

I have one class, which is written in Objective-C :

@interface AEngineBool : AEngineData
 @property BOOL value; 
 @end

And one another view controller class, I access this using respondToSelector like this

 let param: AnyObject = params[0]
 if param.responds(#selector(AEngineBool.value)) {
    let iType: Bool = param.value
// Something
}

and getting an error on param.response() point, which I mention above.

If I changed the if (param.responds(to: #selector(getter: AEngineBool.value))), then I am getting an error Ambiguous use for 'value(forKey:)'.

Answer 1

Ok, it looks like you have 3 problems:

1. are using the wrong signature for responds()
2. value is a getter and it should be labelled as so, and
3. the 'value' property name is ambiguous.

See this:

if param.responds(to: #selector(getter: AEngineBool.value)){
     let iType = param.value // gives error 'value' is ambiguous
     // something?
}

But if i create another BOOL property on your original class, that has a more unique name:

@interface AEngineBool : NSObject
@property BOOL value;
@property BOOL uniquePropertyName;
@end

Then this is all good:

if param.responds(to: #selector(getter: AEngineBool.uniquePropertyName)){
      let iType = param.uniquePropertyName
      // something?
}

So i think value is just to general of a word and collides with value(forKey:) and others...

Answer 2

also can't figure out the error given by XCode, but i would code around it. Would this work for your implementation?

    let param: AnyObject = params[0]
    if param is AEngineBool {
        let iType: Bool = param.value
        // something?
    }