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iosswiftnspredicateresearchkit

iOS Swift Researchkit Predicate issue in Xcode 8.3.3


I am Working Researchkit based application where i am navigating to the question based on the selected option of a single choice question in Xcode 8.3.3 . Unfortunately app crashing dynamically in setting the navigation rule. Earlier in Xcode 8.2.1 i have no issue and working smooth. Please let me know whats going wrong in my code, Following is the crash log:

Could not cast value of type '(predicate : __ObjC.NSPredicate, destinationStepIdentifier : Swift.String)' (0x15fe50570) to '(resultPredicate : __ObjC.NSPredicate, destinationStepIdentifier : Swift.String)' (0x15fe60530). 2017-10-10 07:37:57.530808 Turbo[7440:2981376] Could not cast value of type '(predicate : __ObjC.NSPredicate, destinationStepIdentifier : Swift.String)' (0x15fe50570) to '(resultPredicate : __ObjC.NSPredicate, destinationStepIdentifier : Swift.String)' (0x15fe60530).

           //Question0
    let textChoiceOneText = NSLocalizedString("Choice 1", comment: "")
    let textChoiceTwoText = NSLocalizedString("Choice 2", comment: "")
    let textChoiceThreeText = NSLocalizedString("Choice 3", comment: "")

    // The text to display can be separate from the value coded for each choice:
    let textChoices = [
        ORKTextChoice(text: textChoiceOneText, value: "choice_1" as NSCoding & NSCopying & NSObjectProtocol),
        ORKTextChoice(text: textChoiceTwoText, value: "choice_2" as NSCoding & NSCopying & NSObjectProtocol),
        ORKTextChoice(text: textChoiceThreeText, value: "choice_3" as NSCoding & NSCopying & NSObjectProtocol)
    ]
    let answerFormat = ORKAnswerFormat.choiceAnswerFormat(with: .singleChoice, textChoices: textChoices)
    let questionStepzero = ORKQuestionStep(identifier: String(describing:"singlechoice0"), title: "titel", answer: answerFormat)

    //question1
    let question1 = ORKQuestionStep(identifier: "question1")
    question1.answerFormat = ORKBooleanAnswerFormat()
    //question2
    let question2 = ORKQuestionStep(identifier: "question2")
    question2.answerFormat = ORKBooleanAnswerFormat()

    //Question6
    let question6 = ORKQuestionStep(identifier: "question6")
    question6.answerFormat = ORKBooleanAnswerFormat()


    //Question 7
    let defaultDate = Date()
    let minDate = Date()
    let maxDate = Date()
    let nameQuestionStepTitle = "title message"
    let dateAnswer = ORKDateAnswerFormat(style:ORKDateAnswerStyle.date, defaultDate: defaultDate, minimumDate: minDate, maximumDate: maxDate, calendar: nil)
    let dataPickerQuestionStep7 = ORKQuestionStep(identifier: "datequestion7", title:nameQuestionStepTitle, answer: dateAnswer)


    let steps = [questionStepzero,question1, question2,question6,dataPickerQuestionStep7]
    let task = ORKNavigableOrderedTask(identifier: "task", steps: steps)

    let predicate1 = ORKResultPredicate.predicateForChoiceQuestionResult(with: ORKResultSelector(resultIdentifier: "singlechoice0"), matchingPattern: "choice_1")
    let predicate2 = ORKResultPredicate.predicateForChoiceQuestionResult(with: ORKResultSelector(resultIdentifier: "singlechoice0"), matchingPattern: "choice_2")
    let predicate3 = ORKResultPredicate.predicateForChoiceQuestionResult(with: ORKResultSelector(resultIdentifier: "singlechoice0"), matchingPattern: "choice_3")


    let singleChulesArray:NSMutableArray =  NSMutableArray()

    var dict:NSMutableDictionary = NSMutableDictionary()
    dict.setObject(predicate1, forKey: "predicateInstance" as NSCopying)
    dict.setObject("datequestion7", forKey: "Destination" as NSCopying)
    singleChulesArray.add(dict)
    dict = NSMutableDictionary()

    dict.setObject(predicate2, forKey: "predicateInstance" as NSCopying)
    dict.setObject("question2", forKey: "Destination" as NSCopying)
    singleChulesArray.add(dict)

    dict = NSMutableDictionary()
    dict.setObject(predicate3, forKey: "predicateInstance" as NSCopying)
    dict.setObject("question6", forKey: "Destination" as NSCopying)
    singleChulesArray.add(dict)



    //Static loading of Predicates and Destintionidentifiers
    /*
    let predicateRule1 = ORKPredicateStepNavigationRule(resultPredicatesAndDestinationStepIdentifiers: [
        (resultPredicate: predicate1, destinationStepIdentifier: "datequestion7"),
        (resultPredicate: predicate2, destinationStepIdentifier: "question2"),
        (resultPredicate: predicate3, destinationStepIdentifier: "question6")
        ])
    */

    print("singleChulesArray",singleChulesArray)

    //Dynamic loading of Predicates and Destination identifiers
    var stuff:[(predicate: NSPredicate, destinationStepIdentifier: String)] = [(predicate: NSPredicate, destinationStepIdentifier: String)]()
    for (_, PredicateDict) in singleChulesArray.enumerated()
    {
        stuff += [(predicate: (PredicateDict as AnyObject).value(forKey: "predicateInstance") as! NSPredicate, destinationStepIdentifier: (PredicateDict as AnyObject).value(forKey: "Destination") as! String)]
    }

    let predicateRule = ORKPredicateStepNavigationRule(resultPredicatesAndDestinationStepIdentifiers: stuff as! [(resultPredicate: NSPredicate, destinationStepIdentifier: String)])

    task.setNavigationRule(predicateRule, forTriggerStepIdentifier: "singlechoice0")
    let taskViewController = ORKTaskViewController(task: task, taskRun: nil)
    taskViewController.view.tintColor = TurboConstants.globalAccess.primaryClr
    taskViewController.delegate = self
    present(taskViewController, animated: true, completion: nil)

Solution

  • You are using the ORKPredicateStepNavigationRule initializer incorrectly. The initializer takes an Array of tuples as parameter. You need to pass the tuple's element's names in the initializer:

    let predicateRule = ORKPredicateStepNavigationRule(resultPredicatesAndDestinationStepIdentifiers: [(resultPredicate: predicate1, destinationStepIdentifier: "datequestion7")])
    

    Or with multiple tuples:

    let predicateRule = ORKPredicateStepNavigationRule(resultPredicatesAndDestinationStepIdentifiers: [
                (resultPredicate: predicate1, destinationStepIdentifier: "datequestion7"),
                (resultPredicate: predicate2, destinationStepIdentifier: "question2"),
                (resultPredicate: predicate3, destinationStepIdentifier: "question6"),
                ])
    

    Or dynamically (as in your code above):

    var stuff = [(resultPredicate: NSPredicate, destinationStepIdentifier: String)]()
    for predicateDict in singleChulesArray
    {
        guard
            let predicateDict = predicateDict as? [String: Any],
            let predicate = predicateDict["predicateInstance"] as? NSPredicate,
            let identifier = predicateDict["Destination"] as? String
            else { continue }
        stuff.append((resultPredicate: predicate, destinationStepIdentifier: identifier))
    }
    

    To remove the crash you only needed to change the tuple element name predicate to the correct name resultPredicate. When tuples are used as parameters in a method the naming of the element names has to be exactly as in the method signature. Or you will get a crash.

    I took the liberty to change a bit more in that part of your code. I removed the force casting (which is almost never a good idea) and used optional unwrapping instead. Also I used append to add a new tuple to the stuff array instead of creating a new array (with the tuple as its only element) and then adding that array to the stuff array.