NSOutlineView, using item: AnyObject

Question

I'm creating a NSOutlineView. When implementing the Data Source, although I'm able to create the top hierarchy I can not implement the childHierarchy. The reason is that I can't read the item: AnyObject? which prevents me from returning the right array from the dictionary.

 //MARK: NSOutlineView
var outlineTopHierarchy = ["COLLECT", "REVIEW", "PROJECTS", "AREAS"]
var outlineContents = ["COLLECT":["a","b"], "REVIEW":["c","d"],"PROJECTS":["e","f"],"AREAS":["g","h"]]

//Get the children for item
func childrenForItem (itemPassed : AnyObject?) -> Array<String>{
    var childrenResult = Array<String>()
    if(itemPassed == nil){ //If no item passed we return the highest level of hirarchy
        childrenResult = outlineTopHierarchy
    }else{ 


        //ISSUE HERE:
        //NEED TO FIND ITS TITLE to call the correct child 
        childrenResult = outlineContents["COLLECT"]!  //FAKED, should be showing the top hierarchy item so I could return the right data


    }
    return childrenResult
}


//Data source
func outlineView(outlineView: NSOutlineView, child index: Int, ofItem item: AnyObject?) -> AnyObject{
    return childrenForItem(item)[index]
}

func outlineView(outlineView: NSOutlineView, isItemExpandable item: AnyObject) -> Bool{
    if(outlineView.parentForItem(item) == nil){
        return true
    }else{
        return false
    }
}

func outlineView(outlineView: NSOutlineView, numberOfChildrenOfItem item: AnyObject?) -> Int{
    return childrenForItem(item).count
}


func outlineView(outlineView: NSOutlineView, viewForTableColumn: NSTableColumn?, item: AnyObject) -> NSView? {

    // For the groups, we just return a regular text view.
    if (outlineTopHierarchy.contains(item as! String)) {
        let resultTextField = outlineView.makeViewWithIdentifier("HeaderCell", owner: self) as! NSTableCellView
        resultTextField.textField!.stringValue = item as! String
        return resultTextField
    }else{
        // The cell is setup in IB. The textField and imageView outlets are properly setup.
        let resultTextField = outlineView.makeViewWithIdentifier("DataCell", owner: self) as! NSTableCellView
        resultTextField.textField!.stringValue = item as! String
        return resultTextField
    }

}

}

I used this as a reference, although it's Objective-C implemented

Answer 1

You need to cast the item to the correct type for your outline. Generally you'd want to use a real data model, but for your toy problem with exactly two levels in the hierarchy, this suffices:

func childrenForItem (itemPassed : AnyObject?) -> Array<String>{
    if let item = itemPassed {
        let item = item as! String
        return outlineContents[item]!
    } else {
        return outlineTopHierarchy
    }
}