如何将此ObjC代码转换为swift3？

Question

I am converting my ObjC code to Swift and stucking on this code.

for (id<Delegate> object in Objects)
 {

    .......
    ......

}

Any help would be greatly appreciated!.

Thanks.

Answer 1

You can do something like this

for object in Objects {
     guard let delegateObject = object as? Delegate else {
        continue
    }
    // rest of your loop here
}

Answer 2

Your Objective-C syntax is saying that you have a collection, called Objects , for which the objects conform to some protocol called Delegate . The syntax in Swift is the largely the same:

func callDelegateMethod(for objects: [Delegate]) {
    for object in objects {
        object.someDelegateMethod()
    }
}

Or

func callDelegateMethod(for objects: [Delegate]) {
    objects.forEach { object in
        object.someDelegateMethod()
    }
}

Note, in those examples, I broadened the example to show how objects was declared (ie as an array of objects that conform to Delegate protocol).

If your objects array was something more ambiguous, something for which the conformance to Delegate couldn't be determined at compile-time, (eg an an array of Any , or what have you), you might need to cast it. For example, if you know that everything in objects will conform to Delegate , you could do:

for object in objects as! [Delegate] {
    object.someDelegateMethod()
}

But, as! can be dangerous, as it will crash if any of those casts fail. So if there is any possibility that any of the objects might not conform, you would optionally cast, eg

for object in objects {
    if let object = object as? Delegate {
        object.someDelegateMethod()
    }
}

Or, writing that using functional methods like compactMap (previously called flatMap in Xcode versions prior to 9.3) and forEach :

objects.flatMap { $0 as? Delegate }  // use `compactMap` in Xcode 9.3 and later
    .forEach { object in
        object.someDelegateMethod() 
}

Answer 3

There are two possible options.

Manually

Paste your code in any online converters like Swiftify .

From XCode

Edit-> Convert-> To modern swift code

Then you will get almost exact swift 2.2 or 3 code.