how to retrieve the list of your application’s tiles already on the Microsoft Band 1

Question

Im creating a Microsoft Band 1 application for iOS with Swift This function on the documentation has me going cross eyed. Please help.

I know functions can act as types in Swift i.e.

var exampleFunction: (String, Int) -> String

is a function that takes two parameters, a string and an int and returns a string.

The method I'm looking at says the following in Xcode (Swift language):

tilesWithCompletionHandler(completionHandler: (([AnyObject]!, NSError!) -> Void)!

which I believe is saying, titlesWithCompletionHandler takes in a parameter which is a function of type [AnyObject]!, NSError!) -> Void I'm not sure about the ()! surrounding the whole thing though I know this is forcing a value out of the optional.. thats hard to understand as well.

on the website for the documentation it is written in Objective-c which shows this as the method definition:

[self.client.tileManager tilesWithCompletionHandler:^(NSArray *tiles, NSError *error) {
   if (error){
     // handle error
}}];

what I have attempted is to construct a function that is the type this is asking for:

//I had to create this function to match the parameter that the tilesWithCompletionHandler method required
func errorFunction(tileArray: [AnyObject]!, error: NSError!) -> Void {
    print("hello")
    if((error) != nil) {
        //handle error
        print("error was not nil, meaning an error occurred... :(")
    }
    else {
        print("i got here")
        self.tileArray = tileArray
    }
}

then I created a type and assigned it to this function like so (which fixed the errors Xcode was griping about when I called the method Im trying to use):

let customFunction: (([AnyObject]!, NSError!) -> Void)! = errorFunction

the ()! part around the type still confuses me though

finally I call the function that I'm needing to call to get the tiles and pass in the function I just constructed

myBand.tileManager.tilesWithCompletionHandler( customFunction )

Edit: the error was not related to the problem. The print statements do print now, but I get into the error flow.

Am I going about this the right way?

Also, I'm trying to figure out how to handle the error part of the parameters. Do I need to use a

do {
    try //some code I need to figure out what to write
} catch let error as NSError {
    //code to handle error
}

There's just a lot going on in this method call for me to fully grasp. Any help would be much appreciated. Thank you for your time!

Answer 1

After Larme's comment I was able to get it working with a closure in Swift. I'm curious if the method I was using in my question would of worked...

This is what I did after updating my print statement that was suggested as well which let me learn you can print errors this way too! :

    myBand.tileManager.tilesWithCompletionHandler( {(tiles:[AnyObject]!, error: NSError!) -> Void in
        if((error) != nil) {
            //handle error
            print("Error in .tilesWithCompletionHandler: \(error)")
        }
    })

It's just a closure which apparently is equivalent to a block in Objective-c which I didn't really know about before now (the block part that is).

Thanks for the help everyone!