Xcode跳过JSONObjectWithData

Question

The following code is supposed to load "groups" into a table view, however, the table view is blank:

do {
    if let jsonDataArray = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions(rawValue: 0)) as? NSArray {
        for imageDataDict in jsonDataArray {
            let group = Group(
                id: imageDataDict.valueForKey("id") as! Int,
                name: imageDataDict.valueForKey("name") as! String,
                author: imageDataDict.valueForKey("author") as! Int
            )
            self.dataArray.append(group)
        }
        self.tableView.reloadData()
    }
    print("lol")
} catch {
    // report error
    displayAlertMessage("Error", alertDescription: "Oh man, there was an error!")
}

I tried setting a breakpoint at if let jsonDataArray... and the Xcode stopped at the line. However, when I stepped forward, it directly skipped to print("lol") . I am confused why this is happening. Is it because jsonDataArray is returning nil?

---

EDIT: Here is the full function

func loadSelfieData () {
    // Create HTTP request and set request Body
    let defaults = NSUserDefaults.standardUserDefaults()
    let user_id = defaults.integerForKey("user_id")
    let httpRequest = httpHelper.buildRequest("groups?user_id=\(user_id)", method: "GET",
        authType: HTTPRequestAuthType.HTTPTokenAuth)

    httpHelper.sendRequest(httpRequest, completion: {(data:NSData!, error:NSError!, description:NSMutableString!) in
        if error != nil {
            let errorMessage = self.httpHelper.getErrorMessage(error)
            displayAlertMessage("Error", alertDescription: errorMessage as String)

            return
        }

        var _ :NSError?

        do {
            if let jsonDataArray = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions(rawValue: 0)) as? NSArray {
                for imageDataDict in jsonDataArray {
                    let group = Group(
                        id: imageDataDict.valueForKey("id") as! Int,
                        name: imageDataDict.valueForKey("name") as! String,
                        author: imageDataDict.valueForKey("author") as! Int
                    )
                    self.dataArray.append(group)
                }
                self.tableView.reloadData()
            }
            print("lol")
        } catch {
            displayAlertMessage("Error", alertDescription: "there was an error")
        }
    })
}

Answer 1

You are setting a breakpoint at the call to a function which executes a closure and so if you just try to step through from there it will appear as if the inside is not being executed when in fact, it is. Set a breakpoint at a line inside the execution of the closure, such as at the id line, where you'll then be able to see the status of all your data, if there is any.