swift - Swift KVO 绑定未更新

Question

在我的 macOS 应用程序中，我想将文本与可视 NSDatePicker 结合起来。因此，我制作了一个自定义的 NSDatePicker，单击时会显示一个弹出窗口。

文本选择器使用绑定检查器链接到变量：

我的问题是，虽然在弹出窗口中选择某些内容时文本选择器会在视觉上更新，但绑定值（prop_dateTime）没有更新。

我尝试过的一些方法：

class TextualAndVisualDatePickerElement: NSDatePicker {
    [...]
    func showPopover(sender: NSDatePicker) {
        //using Bond
        self.reactive.objectValue.bidirectionalBind(to: visualDatePicker.reactive.objectValue)

        //using KVO
        visualDatePicker.bind(.value, to: self, withKeyPath: "dateValue", options: [:])

        //using setValue
        _ = self.reactive.objectValue.observeNext(with: {self.setValue($0, forKey: "dateValue")})
        _ = visualDatePicker.reactive.objectValue.observeNext(with: {sender.setValue($0, forKey: "dateValue")})

        //using willChange
        _ = self.reactive.objectValue.observeNext(with: {visualDatePicker.willChangeValue(forKey: "dateValue"); visualDatePicker.dateValue = $0 as! Date; visualDatePicker.didChangeValue(forKey: "dateValue")})
        _ = visualDatePicker.reactive.objectValue.observeNext(with: {self.willChangeValue(forKey: "dateValue"); self.dateValue = $0 as! Date; self.didChangeValue(forKey: "dateValue")})

    }
    [...]
    //using keyPaths
    override public class func keyPathsForValuesAffectingValue(forKey key: String) -> Set<String> {
        if key == "dateValue" {
            return Set(["visualDatePicker.dateValue"])
        }
        if key == "visualDatePicker.dateValue" {
            return Set(["dateValue"])
        }
        return Set([])
    }
}

class ViewController: NSViewController {
    @objc dynamic var objectControllerContent : ObjectControllerContent = ObjectControllerContent()

    @IBOutlet weak var label: NSTextField!
    @IBAction func btnClicked(_ sender: Any) {
        label.stringValue = "prop_dateTime is \(objectControllerContent.prop_dateTime)"
    }
}

class ObjectControllerContent : NSObject {
    @objc dynamic var prop_dateTime : Date?
}

结果：

github项目：https ://github.com/Florrr/VisualNSDatePicker

标签： swiftmacoscocoadatepickerkey-value-observing

Answer 1

设置dateValue或objectValueaNSDatePicker或 anyNSControl不会触发绑定。绑定在 中触发sendAction(_:to:)。

解决方案：

call sendAction(_:to:)，动作和/或目标可以是nil.

datePicker.dateValue = date
datePicker.sendAction(datePicker.action, to: datePicker.target)

或模仿绑定

datePicker.dateValue = date
guard
    let bindingInfo = datePicker.infoForBinding(NSBindingName.value),
    let observedObject = bindingInfo[NSBindingInfoKey.observedObject] as? NSObject,
    let observedKeyPath = bindingInfo[NSBindingInfoKey.observedKeyPath] as? String else {
        return
}
observedObject.setValue(self.dateValue, forKeyPath: observedKeyPath)