在 SWIFT OS X 中以编程方式添加和删除 NSTextField

Posted 2023-02-26

【中文标题】在 SWIFT OS X 中以编程方式添加和删除 NSTextField

【英文标题】：Adding and removing NSTextField programatically in SWIFT OS X

【发布时间】：2015-07-10 12:20:35

【问题描述】：

我正在尝试在表示各种数据点的图形视图上编写文本标签（想象 Excel 中的折线图）。

我使用 tableView 选择数据集。每次选择一个新数据集时，都会重新绘制图表。

我可以使用自定义视图绘制折线图。没问题。

我可以使用从 drawRect() 调用的以下函数来绘制文本标签：

func drawDataPointLabels(size: CGSize)   //size is the view.bounds

    var dataLabelsArray: [(NSColor, String, NSRect)] = []

    // graphDetails contain an array of tuples  [(), (), (), ()] - this represents one graph type = eg Monthly Fees ** there will be a maximum of 12 items in the array
    for graphDetails in graphDetailsArray 

         // each dataPoint object is a tuple (graphType:  columnLabel: columnColor:  columnHeight:  columnNumber: ) representing one dataPoint
        for dataPoint in graphDetails 
            let graphHeight = size.height / 2
            let graphWidth = size.width - graphOrigin.x - rightMargin
            let columnAndGapSize = graphWidth / 25
            let labelX: CGFloat = (graphOrigin.x + columnAndGapSize) + (columnAndGapSize * dataPoint.columnNumber) * 2
            let labelY: CGFloat = dataPoint.columnHeight * (graphHeight - topMargin - bottomMargin)

            // determine the location and frame for the text label to match dataPoint
            let textFrame = NSRect(x: labelX, y: labelY, width: 30, height: 10)
            let dataPointTuple = (dataPoint.columnColor, dataPoint.columnLabel, textFrame)
            dataLabelsArray.append(dataPointTuple)
        

        for dataPoint in dataLabelsArray 
            let (color, label, frameRect) = dataPoint
            let lblDataPoint = NSTextField(frame: frameRect)
            lblDataPoint.stringValue = label
            lblDataPoint.backgroundColor = backgroundColor
            lblDataPoint.textColor = color
            self.addSubview(lblDataPoint)
        
    

但是，当视图更新并呈现新数据集时，我无法弄清楚如何删除数据标签。图表会重绘，但文本标签仍来自先前的数据集。

任何指导/建议将不胜感激。

【参考方案1】：

将以下代码添加到函数顶部已解决了我的问题。

        let subViewsToRemove = self.subviews

        for object in subViewsToRemove 
            object.removeFromSuperview()