小编H.N*_*.N.的帖子

我正在尝试使用发送电子邮件选项设置应用.

我有这个代码:

import Foundation
import MessageUI
import UIKit

class emailClass: UIViewController, MFMailComposeViewControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()

        if !MFMailComposeViewController.canSendMail() {
            print("Mail services are not available")
            return
        }        
        sendEmail() 
    }

    func sendEmail() {      
        let composeVC = MFMailComposeViewController()
        composeVC.mailComposeDelegate = self
        // Configure the fields of the interface.
        composeVC.setToRecipients(["address@example.com"])
        composeVC.setSubject("Hello!")
        composeVC.setMessageBody("Hello this is my message body!", isHTML: false)
        // Present the view controller modally.
        self.present(composeVC, animated: true, completion: nil)
    }

    func mailComposeController(controller: MFMailComposeViewController,
                           didFinishWithResult result: MFMailComposeResult, error: NSError?) {
        // Check …

我试图从给定的点找出高度,但我没有用我的iPad得到它.我已经定义了我的高度变量:

 var altitude: CLLocationDistance = 0.0

我做了这个功能:

       func getAltitude(latitude: CLLocationDistance, longitude: CLLocationDistance) -> CLLocationDistance {

    //Get altitude of touched point
    locationManager.requestWhenInUseAuthorization()
    locationManager.distanceFilter = kCLDistanceFilterNone
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    let touchPointLocation = CLLocation(latitude: latitude, longitude: longitude)
    let altitude = touchPointLocation.altitude

    return altitude

}

例如,当我触摸地图时,我试图在长按中获得这样的高度:

let touchPoint = gestureRecognizer.location(in: self.map)
let coord = map.convert(touchPoint, toCoordinateFrom: self.map)        //now this coord is working ok. Its touched point coordinates

let altitude = getAltitude(latitude: coord.latitude, longitude: coord.longitude)

print(altitude) //I get 0.0 here :(

为什么这是错的？我怎样才能做到这一点？

我正在尝试向地图添加注释。我内部有坐标的点数组。我正在尝试从这些坐标添加注释。

我有这个定义：

var points: [CLLocationCoordinate2D] = [CLLocationCoordinate2D]() 
let annotation = MKPointAnnotation()

点内部具有坐标。我检查了。我这样做：

for index in 0...points.count-1 {
        annotation.coordinate = points[index]
        annotation.title = "Point \(index+1)"
        map.addAnnotation(annotation)
    }

它一直仅添加最后一个注释...而不是全部添加。为什么是这样？顺便说一句，有没有办法删除指定的注释，例如按标题？

我正在做一个项目Swift 3- xcode 8,我正在尝试使用核心数据来保存并在数据库表"用户"中显示一些图像.此图片是其个人资料中的用户照片.

现在我已经设法保存字符串并从核心数据中显示它们,但我在处理图像时遇到了问题.

这是我到目前为止:

将USERS添加到核心数据中

func addUser() {
    let app = UIApplication.shared.delegate as! AppDelegate
    let context = app.persistentContainer.viewContext
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
    request.returnsObjectsAsFaults = false

    let newUser = NSEntityDescription.insertNewObject(forEntityName: "Users", into: context)

    if (firstName.text == "" && lastName.text == "" && contact.text == "" && email.text == "") { //if we have a user profile delete it
        deleteUser()
    } else { // add a new user profile
        newUser.setValue(firstName.text, forKey: "firstName")
        newUser.setValue(lastName.text, forKey: "lastName")
        newUser.setValue(contact.text, …