arrays - 仅针对具有 objective-c 元素的数组的 Swift 扩展可能吗？

Question

大家好，我只想为具有 objective-c 元素的数组添加 Array swift 扩展，这可能吗？

例如:

extension Array where Element:ObjectiveCClass{

 func unionWithoutDuplicatesPropertiesWithArray(array:[Element] ,key:String) -> [Element]{
    var arrayA:[Element]
    var arrayB:[Element]

    if self.count > array.count {
        arrayA = self;
        arrayB = array;
    } else {
        arrayA = array;
        arrayB = self;
    }

    for object in arrayA
    {
        if object.valueForKey(key)
        {
            //do something
        }
    }
    return arrayA
 }
}

Answer 1

试试NSObject？

The root class of most Objective-C class hierarchies, from which subclasses inherit a basic interface to the runtime system and the ability to behave as Objective-C objects.

extension Array where Element: NSObject{

    func unionWithoutDuplicatesPropertiesWithArray(array:[Element] ,key:String) -> [Element]{
        var arrayA:[Element]
        var arrayB:[Element]

        if self.count > array.count {
            arrayA = self;
            arrayB = array;
        } else {
            arrayA = array;
            arrayB = self;
        }

        for object in arrayA
        {
            if object.value(forKey: key) != nil
            {
                //do something
            }
        }
        return arrayA
    }
}

请注意，您没有使用 arrayB 的值。