OSX Swift , 按一下按钮画一条简单的线

Question

为此找了很多，但没有找到匹配的。真的很简单我想画一条线买一个按钮。我有一个来自 NSView 的 class 来进行绘图，它监视一个 var，如果它发生变化则重绘视图。我可以通过更改值来单击鼠标来调用视图，并且它绘制得很好。但我无法让按钮工作。它调用绘图方法但视图未更新？？？我知道它一定很简单，但我就是找不到它。提前致谢。

下面是我的视图 class 和视图控制器。

    //
//  LineDrawer.swift
//  TestDraw3
//
//  Created by Colin Wood on 21/04/17.
//  Copyright © 2017 Colin Wood. All rights reserved.
//

import Cocoa



class LineDrawer : NSView {
// Vars
    var newLinear = NSBezierPath()


    public var QQ: Int = 0 {   // every time QQ changes redraw information in QQ
        didSet{
            boom()    // drawing method
        }
    }



// Methods
    override func draw(_ dirtyRect: NSRect) {
        NSColor.red.set()
        newLinear.lineWidth = 5
        newLinear.lineCapStyle = NSLineCapStyle.roundLineCapStyle
        newLinear.stroke()
    }

    func boom(){  // draw a simple line
        Swift.print("In BooM")
        Swift.print(QQ)
        let lastPt = NSPoint(x: QQ, y: 1)
        newLinear.move(to: lastPt)
        let newPt = NSPoint(x: QQ, y: 50)
        newLinear.line(to: newPt)
        needsDisplay = true
    }

     override func mouseDown(with theEvent: NSEvent) {
        QQ = QQ + 7  // just add 7 so you can see it being drawn after didSet 
    }

}


//
//  ViewController.swift
//  TestDraw3
//
//  Created by Colin Wood on 15/04/17.
//  Copyright © 2017 Colin Wood. All rights reserved.
//

import Cocoa

class ViewController: NSViewController {
// Vars
    @IBOutlet weak var textField: NSTextField!

// Methods
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.

    }

    override var representedObject: Any? {
        didSet {
        // Update the view, if already loaded.

        }
    }


    @IBAction func button(_ sender: Any) {
        let v = LineDrawer()
        v.QQ = 300  // change QQ to call didSet
    }

}

Answer 1

您需要将 LineDrawer 添加为 子视图 。添加它的好地方是 viewDidLoad 方法：

private var line: LinerDrawer!

override func viewDidLoad() {
    super.viewDidLoad()
    line = LinerDrawer()
    line.frame = NSMakeRect(0, 0, 200, 200)
    line.QQ = 300
    line.isHidden = true
    view.addSubview(line)
}

然后在您按下按钮时最终显示它：

@IBAction func button(_ sender: Any) {
    line.isHidden = false
}

您仍然需要为您的 LineDrawer 视图计算出正确的 frame。

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