NSOutlineView, using item: AnyObject - swift

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
}
}