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我正在使用 PDFKit 并且类似于 Apple Preview App，在添加 PDF 注释时，我希望用户能够在页面上移动它们。我在 Github 上创建了一个示例项目。

我尝试子类化 PDFView 并覆盖func mouseDown(with event: NSEvent)and func mouseDragged(with event: NSEvent)。我可以分享该代码，但我有一种直觉，我正朝着错误的方向前进。（我想我无法让该代码工作的事实证实了这种感觉......）

编辑：我已将以下代码添加到我的 PDFView。它可以工作，但不能优雅地工作。它不像预览应用程序的工作方式那样流畅。只是想在这里学习，所以也许有人有更好的方法？

private var annotationBeingDragged:PDFAnnotation?

override func mouseDown(with event: NSEvent) {
    let areaOfInterest = self.areaOfInterest(forMouse: event)
    if areaOfInterest.contains(.annotationArea),
        let currentPage = self.currentPage,
        let annotation = currentPage.annotation(at: self.convert(self.convert(event.locationInWindow, from: nil), to: currentPage)) {

        if annotationBeingDragged == nil {
            annotationBeingDragged = annotation
        } else {
            super.mouseDown(with: event)
        }
    }
    else {
        super.mouseDown(with: event)
    }
}

override func mouseDragged(with event: NSEvent) {

    if let annotation = annotationBeingDragged,
        let currentPage = self.currentPage {
        
            currentPage.removeAnnotation(annotation)
            let currentPoint = self.convert(self.convert(event.locationInWindow, from: nil), to: currentPage)
            annotation.bounds = NSRect(origin: currentPoint, size: annotation.bounds.size)
            currentPage.addAnnotation(annotation)
    }
    else {
        super.mouseDragged(with: event)
    }
}

override func mouseUp(with event: NSEvent) {
    if annotationBeingDragged != nil {
        annotationBeingDragged = nil
        super.mouseDown(with: event)
    }
    else {
        super.mouseUp(with: event)
    }
}
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1 回答 1

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mouseUp它在您的方法更改中对您的代码进行了微小的更改。

super.mouseDown(with: event)

至

super.mouseUp(with: event)

它的工作顺利。

于 2020-10-29T09:43:23.043 回答