Question

我正在尝试在识别长按手势时在iOS CoreData中保存标记的位置。每当我调用手势时，应用程序总是会崩溃。我还将那两个的coreData类型设置为Double。如何以最简单的方式安全地存储coreData中的坐标，因为我对iOS开发还不是很熟悉。

    @IBAction func saveLocation(_ sender: Any) {
    guard let longPress = sender as? UILongPressGestureRecognizer else
    { return }
    if longPress.state == .ended { 
        let touchLocation = longPress.location(in: mapView)
        let coordinate = mapView.convert(touchLocation, toCoordinateFrom: mapView)

        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        let context = appDelegate.persistentContainer.viewContext
        let newLocation = NSEntityDescription.insertNewObject(forEntityName: "GeoData", into: context)
        newLocation.setValue(coordinate.latitude as Double, forKey: "myLatitude")
        newLocation.setValue(coordinate.longitude as Double, forKey: "myLongitude")
        do
        {
           try context.save()
        }
        catch
        {
        //ERROR
        }
    }

}

Answer 1

我创建了一个长按手势并将位置存储到核心数据 -

创建长按手势并在核心数据中保存位置。

let longGesture = UILongPressGestureRecognizer(target: self, action: 
 #selector(longTap(_:)))
 mapView.addGestureRecognizer(longGesture)

func longTap(_ sender: UIGestureRecognizer){
    print("Long tap")
    if sender.state == .ended {
        print("UIGestureRecognizerStateEnded")
        //Do Whatever You want on End of Gesture
        let touchLocation = sender.location(in: mapView)
        let coordinate = mapView.convert(touchLocation, 
toCoordinateFrom: mapView)
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        let context = appDelegate.persistentContainer.viewContext
        let newLocation = 
NSEntityDescription.insertNewObject(forEntityName: "GeoData", into: 
context)
        newLocation.setValue(coordinate.latitude as Double, forKey: 
"myLatitude")
        newLocation.setValue(coordinate.longitude as Double, forKey: 
"myLongitude")
        do
        {
            try context.save()
        }
        catch
        {
            //ERROR
            print(error)
        }
    }
    else if sender.state == .began {
        print("UIGestureRecognizerStateBegan.")
        //Do Whatever You want on Began of Gesture
    }
}

如何在CoreData中保存位置

1 个答案: