swift - NSTextField 上的自定义边框

Question

我想自定义 NSTextFields 的边框。我四处搜索，我相当确定这需要在 drawInterior(withFrame:in:) 的 NSTextFieldCell 中完成，但我不确定如何做。

具体来说，我只想要一个底部边框，比正常情况稍微厚一些。

Answer 1

您可能应该阅读NSCell 的文档。它说您必须在 draw(withFrame:in) 函数中绘制边框，并且如果您覆盖 draw( withFrame:in)。此外，您必须覆盖 cellSize 并返回将新边框考虑在内的适当大小。我将示例更新为完整的解决方案。在 Github 上创建了示例项目

/**
 Creates an custom border, that is just a line underneath the NSTextField.
 */
class CustomBorderTextFieldCell: NSTextFieldCell {
    // How thick should the border be
    let borderThickness: CGFloat = 3

    // Add extra height, to accomodate the underlined border, as the minimum required size for the NSTextField
    override var cellSize: NSSize {
        let originalSize = super.cellSize
        return NSSize(width: originalSize.width, height: originalSize.height + borderThickness)
    }

    // Render the custom border for the NSTextField
    override func draw(withFrame cellFrame: NSRect, in controlView: NSView) {
        // Area that covers the NSTextField itself. That is the total height minus our custom border size.
        let interiorFrame = NSRect(x: 0, y: 0, width: cellFrame.width, height: cellFrame.height - borderThickness)

        let path = NSBezierPath()
        path.lineWidth = borderThickness
        // Line width is at the center of the line.
        path.move(to: NSPoint(x: 0, y: cellFrame.height - (borderThickness / 2)))
        path.line(to: NSPoint(x: cellFrame.width, y: cellFrame.height - (borderThickness / 2)))
        NSColor.black.setStroke()
        path.stroke()

        // Pass in area minus the border thickness in the height
        drawInterior(withFrame: interiorFrame, in: controlView)
    }
}

这是结果