Question

您好我需要帮助才能选择并仅显示距用户当前位置5公里的水果。我必须在表视图单元格中显示它们。这是我的代码：

@IBOutlet weak var LabelTest: UILabel!

var locationManager = CLLocationManager()
var lat = Double()
var long = Double()
var latitude = Double()
var longitude = Double()

struct Fruit {
    let name : String
    let location : CLLocation
    let latitude : Double
    let longitude: Double
    let imageURL : NSURL
    let description : String
    func distanceTo(location:CLLocation) -> Int
    {
        let distanceMeters = location.distanceFromLocation(self.location)
        let distanceKilometers = distanceMeters / 1000.00
        return Int(round(100 * distanceKilometers) / 100)
    }

}
var fruits = [Fruit]()


func parseFruits() {

    if CalculateDistance() < 5 {
    guard let url = NSBundle.mainBundle().URLForResource("cities", withExtension: "json"), jsonData = NSData(contentsOfURL: url) else {
        print("Error finding JSON File")
        return
    }

    let jsonObject = JSON(data: jsonData)

    let fruitArray = jsonObject["fruits"].arrayValue
    for aFruit in fruitArray {
       let name = aFruit["Name"].stringValue
        let latitude = aFruit["Latitude"] as! Double
        let longitude = aFruit["Longitude"] as! Double
        let location = CLLocation(latitude: latitude, longitude: longitude)
       let imageURL = aFruit["Picture"].stringValue
    let description = aFruit["Description"].stringValue

        let fruit = Fruit(name: name,location: location,latitude:latitude,longitude: longitude, imageURL: NSURL(string:imageURL)!, description: description)
        fruits.append(fruit)
                }

    self.tableView.reloadData()
}
}
override func viewDidLoad() {
    self.locationManager.requestWhenInUseAuthorization()
    if CLLocationManager.locationServicesEnabled() {
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
    }
    super.viewDidLoad()
    parseFruits()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem()
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location:CLLocationCoordinate2D = manager.location!.coordinate
    lat = location.latitude
    long = location.longitude
}

func CalculateDistance() -> Int{
    let userLocation = CLLocation(latitude: lat, longitude: long)
    let destinationLocation = CLLocation(latitude:latitude, longitude: longitude)// latitude and longitude from the json file
    let distance = userLocation.distanceFromLocation(destinationLocation)

    return roundToFive(distance)
}

private func roundToFive(x : Double) -> Int {
    return 5 * Int(round(x / 5.0))
}


func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
    print("Error")
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return fruits.count
    }



override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
     let cell: TableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell") as!  TableViewCell
     let fruit = fruits[indexPath.row]
    cell.CellTitle.text = fruit.name
    cell.CellDescription.text = fruit.description



    let image = UIImage(data: NSData(contentsOfURL:(string: fruit.imageURL))!)
    cell.CellImage.image = image

    return cell


                }

在TableView单元格中，我只需要显示离用户位置5公里的水果。我试着做点什么，但似乎它没有用。任何想法如何解决它？

Answer 1

就这样做：

// Update your CalculateDistance method to the following
func CalculateDistance(lat: Double, long: Double) -> Int{
    let userLocation = CLLocation(latitude: lat, longitude: long)
    let destinationLocation = CLLocation(latitude:latitude, longitude: longitude)// latitude and longitude from the json file
    let distance = userLocation.distanceFromLocation(destinationLocation)

    return roundToFive(distance)
}

// When you parse your fruits, you can make the check if it´s within 5km then you can add it to your array or add it to a separate array
if (CalculateDistance(latitude, longitude) <= 5000{
    fruits.append(fruit)
}

Answer 2

您的CalculateDistance方法有何功能？你应该过滤你的阵列。

func shouldShowFruit(fruit: Fruit) -> Bool{
  let userLocation = CLLocation(latitude: lat, longitude: long)
  let destinationLocation = CLLocation(latitude:fruit.latitude, longitude: fruit.longitude)
  let distance = userLocation.distanceFromLocation(destinationLocation)

  return distance < 5000
}

为数组中的每个项调用此方法，如果返回false则从数组中删除。

如何在TableView单元格中选择和显示特定信息？

2 个答案: