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Khoa Pham
Khoa Pham

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How to make scrollable NSTextView in AppKit

When adding NSTextView in xib, we see it is embedded under NSClipView. But if we try to use NSClipView to replicate what's in the xib, it does not scroll.

To make it work, we can follow Putting an NSTextView Object in an NSScrollView and How to make scrollable vertical NSStackView to make our ScrollableInput

For easy Auto Layout, we use Anchors for UIScrollView.

Things worth mentioned for vertical scrolling

textContainer.heightTracksTextView = false
textView.autoresizingMask = [.width]
textView.isVerticallyResizable = true
class ScrollableInput: NSView {
    let scrollView = NSScrollView()
    let textView = NSTextView()

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)

        let rect = CGRect(
            x: 0, y: 0,
            width: 0, height: CGFloat.greatestFiniteMagnitude
        )

    let layoutManager = NSLayoutManager()

        let textContainer = NSTextContainer(size: rect.size)
        layoutManager.addTextContainer(textContainer)
        textView = NSTextView(frame: rect, textContainer: textContainer)
        textView.maxSize = NSSize(width: 0, height: CGFloat.greatestFiniteMagnitude)

        textContainer.heightTracksTextView = false
        textContainer.widthTracksTextView = true

        textView.isRichText = false
        textView.importsGraphics = false
        textView.isEditable = true
        textView.isSelectable = true
        textView.font = R.font.text
        textView.textColor = R.color.text
        textView.isVerticallyResizable = true
        textView.isHorizontallyResizable = false

        addSubview(scrollView)
        scrollView.hasVerticalScroller = true
        scrollView.drawsBackground = false
        scrollView.drawsBackground = false
        textView.drawsBackground = false

        activate(
            scrollView.anchor.edges
        )

        scrollView.documentView = textView
        textView.autoresizingMask = [.width]
    }

    required init?(coder decoder: NSCoder) {
        fatalError()
    }
}

Original post https://github.com/onmyway133/blog/issues/330

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