How to correctly add a row to NSTableView - swift

Question

Firstly I must note that this is my first GUI-app (XIB) in Swift, in other words I am working on and trying to learn Swift and MacOS software development. I have looked through several questions, here at Stack, as well as the Apple documentation on NSTableView, but I'm stuck.
Trying to make a simple app to read some attributes of selected files. I have a custom NSView where the user drags and drop in a file and it reads some attributes off it - which is ok.
>>> print("\(fileDataToShow)\n\(resultTable)")
Optional([["filename": "foo.jpeg", "state": "1"],["filename": "bar.jpeg", "state": "1"]])
Optional(<NSTableView: 0x101203070>)
The #IBOutlet weak var resultTable: NSTableView!, at top of the file containing the class/NSView, show that it is connected, MainMenu.XIB—ResultTable.
I have come up with following code, in an attempt to display the data in the NSTableView, from my custom class View: NSView {
override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
<...>
func numberOfRowsInTableView(in tableView: NSTableView) -> Int {
return fileDataToShow?.count ?? 0
}
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView?{
var result:NSTableCellView
result = tableView.makeView(withIdentifier: (tableColumn?.identifier)!, owner: self) as! NSTableCellView
result.textField?.stringValue = fileDataToShow?[row][(tableColumn?.identifier.rawValue)!]! as! String
return result
}
resultTable?.beginUpdates()
// print(type(of:fileDataToShow)) // Optional<Array<Dictionary<String, Any>>>
resultTable.insertRows(at: IndexSet(integer: fileDataToShow?.count ?? 0), withAnimation: .effectFade)
resultTable.reloadData()
resultTable?.endUpdates()
}
Content of fileDataToShow is ok, but the other lines of code, .beginUpdates() / .insertRows(.., etc. doesn't seem to have any action.
As mentioned, I can't figure this out and don't know where or how to figure this... Anyone got some tips and/or pointers for me ?
I have defined all of the keys in fileDataToShow to correspond with the Identifiers in my XIB.
Hope I have managed to explain my problem in an ok way.
EDIT:
The Debug area giving following output when I run my app:
*** Illegal NSTableView data source (<NSObject: 0x600000000b90>). Must implement numberOfRowsInTableView: and tableView:objectValueForTableColumn:row:
EDIT2/Update:
Thank you #vadian, but I still haven't managed to fix this, here's a little update.
Here's my whole file, DropZone.swift:
```
class DropView: NSView/*, NSTableViewDataSource, NSTableViewDelegate*/ {
#IBOutlet weak var resultTable: NSTableView!
let dropZoneEnteredBackgroundColor = CGColor(red: 165/255, green: 165/255, blue: 165/255, alpha: 1.0)
let dropZoneExitedBackgroundColor = CGColor(red: 200/255, green: 200/255, blue: 200/255, alpha: 1.0)//NSColor.gray.cgColor
required init?(coder: NSCoder) {
super.init(coder: coder)
self.wantsLayer = true
self.layer?.backgroundColor = dropZoneExitedBackgroundColor
registerForDraggedTypes([NSPasteboard.PasteboardType.URL,
NSPasteboard.PasteboardType.fileURL])
}
override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
self.layer?.backgroundColor = dropZoneEnteredBackgroundColor
return .copy
}
override func draggingEnded(_ sender: NSDraggingInfo) {
self.layer?.backgroundColor = dropZoneExitedBackgroundColor
}
override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
guard let pasteboard = sender.draggingPasteboard.propertyList(forType:
NSPasteboard.PasteboardType(rawValue: "NSFilenamesPboardType")) as?
NSArray else {return false}
var droppedItems: [String: String] = [:]
for path in pasteboard {
guard let fullPath = path as? String else { return false }
let fileManager = FileManager.default
var isDir: ObjCBool = false
if fileManager.fileExists(atPath: fullPath, isDirectory:&isDir) {
if isDir.boolValue {
// the dropped item exists and it's a directory
droppedItems[path as! String] = "folder"
}
else {
// file exists and it's not a directory, hence a normal file
droppedItems[path as! String] = "file"
}
}
}
do {
var fileDataToShow = [[String:Any]]()
for object in droppedItems {
if object.value == "file" {
do {
//let fullPath = object.key
let attributes = try object.key.extendedAttributes() // Array<String>
let filename = object.key.fileName() + "." + object.key.fileExtension()
fileDataToShow.append(["state": "1",
"filename": filename,
"metadata":removed_attributes
])
}
catch {
debugPrint("Error info: \(error)")
}
}
else if object.value == "folder" {
// TODO
}
}
func numberOfRows(in tableView: NSTableView) -> Int {
return fileDataToShow.count
}
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView?{
let cell = tableView.makeView(withIdentifier: tableColumn?.identifier ?? NSUserInterfaceItemIdentifier(rawValue: ""), owner: self) as! NSTableCellView
// This line could crash if there values which are not String
cell.textField?.stringValue = fileDataToShow[row][tableColumn?.identifier.rawValue ?? ""] as! String
return cell
}
let insertionIndex = fileDataToShow.count
//debugPrint(resultTable) // Optional(<NSTableView: 0x10100ba10>)
//debugPrint(fileDataToShow) // [["filename": "img1.jpeg", "metadata": ["com.apple.metadata..", "com.a..."], "state": "1"]]
resultTable.insertRows(at: IndexSet(integer: insertionIndex), withAnimation: .effectGap)
} // do
return true
}
}
This is now giving the following error:
*** Canceling drag because exception 'NSTableViewException' (reason 'NSTableView error inserting/removing/moving row 2 (numberOfRows: 0).') was raised during a dragging session
Sorry, but have had trouble with this since the last reply from #vadian, so have to ask again.
What am I doing wrong?
EDIT 3:
Appreciate your answers, #vadian, but I do not get this. I have places the numberOfRows and tableView function right underneath the init function. And implemented following code last in the do-block, in an attempt to update the table:
resultTable.beginUpdates()
var i = 0
for row in fileDataToShow {
print("state:",row["state"]!) // 1
print("filename:",row["filename"]!) // file.jpg
print("metadata:",row["metadata"]!) // ["com.apple.metadata..", "com.a..."]
resultTable.insertRows(at: IndexSet(integer: i), withAnimation: .effectFade)
i += 1
}
resultTable.endUpdates()
New lines is added to the table, but they are all empty. How do I - in any way - bind fileDataToShow against resultTable.insertRows.
If you understand my poor spelling and fussy questions :)
Swift is hard but fun to learn!

Answer 1

There are many issues in the code.
numberOfRowsInTableView is numberOfRows(in tableView: in Swift 3+.
The datasource / delegate methods must be on the top level in the class, not in performDragOperation.
You are using too many question marks.
Don not declare the data source array as optional, declare it as empty non-optional array.
var fileDataToShow = [[String:Any]]()
func numberOfRows(in tableView: NSTableView) -> Int {
return fileDataToShow.count
}
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView?{
let cell = tableView.makeView(withIdentifier: tableColumn.identifier!, owner: self) as! NSTableCellView
// This line could crash if there values which are not String
cell.textField?.stringValue = fileDataToShow[row][tableColumn.identifier!.rawValue)] as! String
cell result
}
To insert a row with animation don't call reloadData(). Get the last index of the array, append the item to the array and insert the row.
Begin-/endUpdates is useless
let insertionIndex = fileDataToShow.count
fileDataToShow.append([:]) // append some suitable dictionary
resultTable.insertRows(at: IndexSet(integer: insertionIndex), withAnimation: .effectGap)