如何在Xcode Swift中从其他视图引用数组？

Question

I have a question regarding how to refer to an array from other view (other cocoa touch file) in Swift.

I created a project where there are two views: BeerInfoView and BeerRatingView. BeerRatingView has a slider button (for rating beer from 1 to 5) and a text view field (for text review), and the values from both slider and textview field are currently saved locally by NSUserDefaults [ eg NSUserDefaults.standardUserDefaults().setObject(writeReview, forKey:"writeReview"); ].

BeerInfoView contains a table which will list all the reviews posted from the BeerRatingView (prototype cell has three labels that will contain rating, text review, etc). Currently, BeerInfoView.swift contains a hardcoded array so the table only displays a limited list of pre-written reviews.

What I want to do is to make the app automatically append and put the locally saved data into an aforementioned hardcoded array every time a user clicks on the "Post" button from the BeerRatingView, but I'm having a hard time because I'm not sure how to call / refer to an array from other view (BeerInfoView) in the BeerRatingView.

Here are portions of codes from BeerInfoView.swift and BeerRatingView.swift:

------- BeerInfoView.swift ---------

var arrayOfBeerUsers: [BeerUser] = [BeerUser]()  

func setUpBeerUsers() {
    var user1 = BeerUser(username: "dave", review: "pretty meh", rating: 2)
    var user2 = BeerUser(username: "liz", review: "pretty good", rating: 4)
    var user3 = BeerUser(username: "michael", review: "I can make it better", rating: 1)

    arrayOfBeerUsers.append(user1)
    arrayOfBeerUsers.append(user2)
    arrayOfBeerUsers.append(user3)
}

---

------- BeerRatingView.swift -----------

@IBAction func postButtonTapped(sender: AnyObject) {

    let writeReview = writeReviewTextView.text

    if (writeReview == "Write a Review:") {
        displayMyAlertMessage("review field cannot be empty!")
        return
    }
    // check if user didn't move around the slider
    else if (displayRatingLabel.text == "Move slider to rate from 1 to 5!") {
        displayMyAlertMessage("You didn't leave the rating!")
        return
    }
    else {

        // saving "text review" locally
        NSUserDefaults.standardUserDefaults().setObject(writeReview, forKey:"writeReview");

        NSUserDefaults.standardUserDefaults().synchronize();

        let textReviewStored = NSUserDefaults.standardUserDefaults().stringForKey("writeReview");



        var beerInfoViewController: BeerInfoViewController = self.storyboard?.instantiateViewControllerWithIdentifier("BeerInfoViewController") as BeerInfoViewController

        let beerArray = beerInfoViewController.arrayOfBeerUsers    //// is this how you refer to an array from BeerInfoView??

        beerArray.append(username: usernameStored, review: textReviewStored, rating: ratingStored)


        self.dismissViewControllerAnimated(true, completion:nil);

    }

} 

---

Answer 1

Swift arrays are value types, and as such they are passed not by reference but by value, which means a copy is created when an array is passed to a function, assigned to a variable, etc.

In order to pass an array (and more generally any value type) to a function by reference, you can use the inout modifier in the function declaration, and use the reference operator & when passing the argument to the function. In your case:

func ExcLowerDidFinish(controller: String, inout Array:[Int])

and:

delegate!.ExcLowerDidFinish(self, Array: &ExcUpperArray)

Off topic: note that by convention in swift functions/methods and variables/parameters names start with lowercase, whereas types (classes, structs, etc.) start with uppercase. Your code may be hard to read by other Swift developers

And refer to the url..

http://www.raywenderlich.com/75289/swift-tutorial-part-3-tuples-protocols-delegates-table-views