NSProgressIndicator 绑定不执行任何操作

Question

我正在尝试将

NSProgressIndicator

绑定到

Progress

，但是使用以下代码，即使在两个计时器触发之后，我也只能得到一个不确定的进度指示器，其中蓝色条永远左右弹跳。根据文档：

当totalUnitCount或completedUnitCount的值小于零或者两个值都为零时，进度是不确定的。 我做错了什么？

class ViewController: NSViewController {
    
    let progress = Progress()

    override func loadView() {
        view = NSView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
        let progressIndicator = NSProgressIndicator(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
        progressIndicator.bind(.isIndeterminate, to: progress, withKeyPath: "isIndeterminate")
        progressIndicator.bind(.value, to: progress, withKeyPath: "completedUnitCount")
        progressIndicator.bind(.maxValue, to: progress, withKeyPath: "totalUnitCount")
        progressIndicator.startAnimation(nil)
        view.addSubview(progressIndicator)
        
        progress.completedUnitCount = 3
        progress.totalUnitCount = 10
        Timer.scheduledTimer(withTimeInterval: 1, repeats: false) { _ in
            print(1)
            self.progress.completedUnitCount = 6
        }
        Timer.scheduledTimer(withTimeInterval: 6, repeats: false) { _ in
            print(2)
            self.progress.completedUnitCount = 0
            self.progress.totalUnitCount = 0
        }
    }

}

Answer 1

Cocoa Bindings 使用 Objective-C，Objective-C 属性的名称是

indeterminate

。使用

#keyPath

字符串表达式来获取正确的关键路径。

progressIndicator.bind(.isIndeterminate, to: progress, withKeyPath: #keyPath(NSProgressIndicator.isIndeterminate))