How to change font size of NSTableHeaderCell - swift

Question

I am trying to change the font size of my NSTableView within my code to allow the user to change it to their liking.
I was successful by changing the font size of each NSTableCellView but failed to do so by the header cells.
I was trying to do it like this
let headerCell = NSTableHeaderCell()
let font = NSFont(name: "Arial", size: 22.0)
headerCell.stringValue = "firstname"
headerCell.font = font
customerTable.tableColumns[0].headerCell = headerCell
The stringValue of the header cell will be set accordingly but the size does not change. How can I change the font size of my headers?
Thanks
Oliver

Answer 1

So, finally I was only able to solve this with subclassing NSTableHeaderCell. It was somehow strange as Swift and Cocoa always tend to favor composition over inheritance but anyway.
Swift 3.1
final class CustomTableHeaderCell : NSTableHeaderCell {
override init(textCell: String) {
super.init(textCell: textCell)
self.font = NSFont.boldSystemFont(ofSize: 18) // Or set NSFont to your choice
self.backgroundColor = NSColor.white
}
required init(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func draw(withFrame cellFrame: NSRect, in controlView: NSView) {
// skip super.drawWithFrame(), since that is what draws borders
self.drawInterior(withFrame: cellFrame, in: controlView)
}
override func drawInterior(withFrame cellFrame: NSRect, in controlView: NSView) {
let titleRect = self.titleRect(forBounds: cellFrame)
self.attributedStringValue.draw(in: titleRect)
}
}

Answer 2

Changing attributedStringValue will do the trick
override func viewDidLoad() {
super.viewDidLoad()
tableView.tableColumns.forEach { (column) in
column.headerCell.attributedStringValue = NSAttributedString(string: column.title, attributes: [NSFontAttributeName: NSFont.boldSystemFont(ofSize: 18)])
// Optional: you can change title color also jsut by adding NSForegroundColorAttributeName
}
}
https://i.stack.imgur.com/IXJyu.png

Answer 3

You can create a NSTableHeaderCell subclass and implement the property you want to change.
In Objective-C (I'm not good at Swift):
#implementation CustomTableHeaderCell
-(NSFont *)font {
return [NSFont fontWithName:#"Arial" size:22];
}
// you can alse custom textColor
-(NSColor *)textColor {
return [NSColor redColor];
}
#end
Assign CustomTableHeaderCell:
CustomTableHeaderCell *headerCell = [[CustomTableHeaderCell alloc] init];
headerCell.stringValue = #"Header title";
self.tableView.tableColumns[0].headerCell = headerCell;
In Cocoa, there are many things you can't change its style by cell.font = ..., you need to create a subcalss.