Question

MyView具有用户提供的文本，图像等。目标是让用户能够将图像从那里拖动到图像可以去的任何地方。代码是从GitHub示例定制的。代码的每个部分都按预期工作 - NSDraggingSource协议中的所有函数都在预期时被调用 - 并且拖动的图像看起来就像它拖动时一样。但是在任何目的地都没有下降，例如，我可以删除从其他应用程序拖动的图像。我错过了什么防止跌落？

    class MyView: NSView, NSDraggingSource {
var mouseDownEvent: NSEvent?

override func drawRect(dirtyRect: NSRect) {
    super.drawRect(dirtyRect)
}

func draggingSession(session: NSDraggingSession, sourceOperationMaskForDraggingContext context: NSDraggingContext) -> NSDragOperation {
    return .Copy
}

func draggingSession(session: NSDraggingSession, endedAtPoint screenPoint: NSPoint, operation: NSDragOperation) {
}

func draggingSession(session: NSDraggingSession, willBeginAtPoint screenPoint: NSPoint) {
}

func draggingSession(session: NSDraggingSession, movedToPoint screenPoint: NSPoint) {
}

override func mouseDown(theEvent: NSEvent) {
    self.mouseDownEvent = theEvent
}

override func mouseDragged(theEvent: NSEvent) {
    let mouseDown = self.mouseDownEvent!.locationInWindow
    var point: NSPoint = theEvent.locationInWindow
    point = anotherView!.convertPoint(point, toView: nil)

    if CGRectContainsPoint(someObject.rect, point) {
        let image = (someObject.contents as! NSImage)
        let draggingItem = NSDraggingItem(pasteboardWriter: image)
        let draggingFrameOrigin = convertPoint(mouseDown, fromView: nil)
        let draggingFrame = NSRect(origin: draggingFrameOrigin, size: image.size).offsetBy(dx: -image.size.width / 2, dy: -image.size.height / 2)
        draggingItem.draggingFrame = draggingFrame
        draggingItem.imageComponentsProvider = {
            let component = NSDraggingImageComponent(key: NSDraggingImageComponentIconKey)
            component.contents = image
            component.frame = NSRect(origin: NSPoint(), size: draggingFrame.size)
            return [component]
        }
        beginDraggingSessionWithItems([draggingItem], event: mouseDownEvent!, source: self)
    }
}

}

可能与NSView而不是NSImageView的拖动有关吗？我向image提供draggingItem，但这只是为了拖动视觉而不是删除的内容？

谢谢！

为什么NSImage会拖延但不会掉线？

0 个答案: