Sample code for creating a NSTextField "label"?

Question

In my desktop Mac OS X app, I'd like to programatically create a NSTextField "label" which has the same behavior and properties as a typical label created in Interface Builder.

I usually use (and very much like) IB, but in this case it must be done programatically.

Try as I might, I can't seem to find the combination of method calls that will programatically produce the same label-y behavior as a "Label" dragged from the IB View Library palette.

Can anyone provide or point out some example code of how to do this programatically? Thx.

Answer 1

A label is actually an instance of NSTextField, a subclass of NSView. So, since it is a NSView, it has to be added to another view.

Here's a working code:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {     NSTextField *textField;      textField = [[NSTextField alloc] initWithFrame:NSMakeRect(10, 10, 200, 17)];     [textField setStringValue:@"My Label"];     [textField setBezeled:NO];     [textField setDrawsBackground:NO];     [textField setEditable:NO];     [textField setSelectable:NO];     [view addSubview:textField]; } 

Answer 2

macOS 10.12 and Later

Starting with macOS 10.12 (Sierra), there are three new NSTextField constructors:

• NSTextField(labelWithString:), which the header file comment says “Creates a non-wrapping, non-editable, non-selectable text field that displays text in the default system font.”

• NSTextField(wrappingLabelWithString:), which the header file comment says “Creates a wrapping, non-editable, selectable text field that displays text in the default system font.”

• NSTextField(labelWithAttributedString:), which the header file comment says “Creates a non-editable, non-selectable text field that displays attributed text. The line break mode of this field is determined by the attributed string's NSParagraphStyle attribute.”

I tested the ones that take a plain (non-attributed string), and they create text fields that are similar to, but not precisely the same as, the text fields created in a storyboard or xib.

The important difference is that both constructors create a text field with textBackgroundColor (normally pure white) as its background color, while the storyboard text field uses controlColor (normally about 90% white).

Unimportantly, both constructors also set their fonts by calling NSFont.systemFont(ofSize: 0) (which produces a different NSFont object than my code below, but they wrap the same underlying Core Text font).

The wrappingLabelWithString: constructor sets the field's isSelectable to true. (This is documented in the header file.)

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macOS 10.11 and Earlier

I compared four NSTextField instances: one created by dragging a “Label” to a storyboard, another created by dragging a “Wrapping Label” to a storyboard, and two in code. Then I carefully modified properties of the code-created labels until all their properties were exactly the same as the storyboard-created labels. These two methods are the result:

extension NSTextField {      /// Return an `NSTextField` configured exactly like one created by dragging a “Label” into a storyboard.     class func newLabel() -> NSTextField {         let label = NSTextField()         label.isEditable = false         label.isSelectable = false         label.textColor = .labelColor         label.backgroundColor = .controlColor         label.drawsBackground = false         label.isBezeled = false         label.alignment = .natural         label.font = NSFont.systemFont(ofSize: NSFont.systemFontSize(for: label.controlSize))         label.lineBreakMode = .byClipping         label.cell?.isScrollable = true         label.cell?.wraps = false         return label     }      /// Return an `NSTextField` configured exactly like one created by dragging a “Wrapping Label” into a storyboard.     class func newWrappingLabel() -> NSTextField {         let label = newLabel()         label.lineBreakMode = .byWordWrapping         label.cell?.isScrollable = false         label.cell?.wraps = true         return label     }  } 

If you use one of these methods, don't forget to set your field's frame, or turn off its translatesAutoresizingMaskIntoConstraints and add constraints.

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Here is the code I used to compare the different text fields, in case you want to check:

import Cocoa  class ViewController: NSViewController {      @IBOutlet var label: NSTextField!     @IBOutlet var multilineLabel: NSTextField!      override func loadView() {         super.loadView()     }      override func viewDidLoad() {         super.viewDidLoad()          let codeLabel = NSTextField.newLabel()         let codeMultilineLabel = NSTextField.newWrappingLabel()          let labels = [label!, codeLabel, multilineLabel!, codeMultilineLabel]          for keyPath in [             "editable",             "selectable",             "allowsEditingTextAttributes",             "importsGraphics",             "textColor",             "preferredMaxLayoutWidth",             "backgroundColor",             "drawsBackground",             "bezeled",             "bezelStyle",             "bordered",             "enabled",             "alignment",             "font",             "lineBreakMode",             "usesSingleLineMode",             "formatter",             "baseWritingDirection",             "allowsExpansionToolTips",             "controlSize",             "highlighted",             "continuous",             "cell.opaque",             "cell.controlTint",             "cell.backgroundStyle",             "cell.interiorBackgroundStyle",             "cell.scrollable",             "cell.truncatesLastVisibleLine",             "cell.wraps",             "cell.userInterfaceLayoutDirection"         ] {             Swift.print(keyPath + " " + labels.map({ ($0.value(forKeyPath: keyPath) as? NSObject)?.description ?? "nil" }).joined(separator: " "))         }     } }