如何快速检查@NSManaged属性是否为nil？

Question

I am adding a new property to an existing data set. I need to take corrective action (such as setting it to a default value) if the value for that property that I get from my Parse.com backend does not exist. I have gone through various solutions posted here and they do not work, I have put the Xcode error message as comments in the code below. I have tried it both in Xcode 6.4 and in Xcode 7.0 beta 5 as another post had suggested that optional NSManaged is properly handled in Xcode 7.0 Beta 2.

class MyObject: PFObject, PFSubclassing {
@NSManaged private(set) var newPoperty: Bool // No probs here but cannot check nil, see later on..
// @NSManaged private(set) var newProperty: Bool? // ! Property cannot be marked NSManaged as its type cannot be represented in Objective-C

private func initLaterProperties(object: MyObject) {

if (object.newProperty == nil ) {//Does not work with following messages
// Xcode 7.0 Beta 5: ! Binary operator '==' cannot be applied to operands of type Bool and nil
// Xcode 6.4: No operator found matching the operands



// Do something
}

if let test = object.newProperty { // Does not work with following message
//! Initializer for conditional binding must have Optional type, not 'Bool'
}
else {
//Do something


}
}

}

Answer 1

Since this has to be an Objective-C-compatible property, do what you would have done if you had been writing this code in Objective-C! In Objective-C, a Bool cannot be nil - it is not an object. Instead, you'd use NSNumber, which has methods to hold a boolean ( init(bool:) ) and to extract a boolean ( boolValue ). So make this an NSNumber? and adjust the rest of your code accordingly.