Set the placeholder string for NSTextView

Question

Is there any way to set the placeholder string for NSTextView like that in NSTextField? I have checked the property but couldn't find it. I have searched some questions but there isn't a proper explanation.

Answer 1

Look for this. It's may be a better approach!

final class CustomTextView: NSTextView {

    private var placeholderAttributedString: NSAttributedString? = NSAttributedString(string: "Your placeholder string here")
    private var placeholderInsets = NSEdgeInsets(top: 0.0, left: 4.0, bottom: 0.0, right: 4.0)

    override func becomeFirstResponder() -> Bool {
        self.needsDisplay = true
        return super.becomeFirstResponder()
    }

    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)

        guard string.isEmpty else { return }
        placeholderAttributedString?.draw(in: dirtyRect.insetBy(placeholderInsets))
    }
}

extension NSRect {
    func insetBy(_ insets: NSEdgeInsets) -> NSRect {
        return insetBy(dx: insets.left + insets.right, dy: insets.top + insets.bottom)
        .applying(CGAffineTransform(translationX: insets.left - insets.right, y: insets.top - insets.bottom))
    }
}

Answer 2

Swift 4

As it turns out, there already seems to be a placeholderAttributedString property in NSTextView that isn't exposed publicly. Thus, you can simply implement it in your own subclass and get the default placeholder behaviour (similar to NSTextField).

class PlaceholderTextView: NSTextView {
     @objc var placeholderAttributedString: NSAttributedString?
}

And if this property will be made available in the future, you only need to use NSTextView instead of this subclass.