准备不使用tabbarcontroller调用segue

Question

我正在使用Xcode 8和swift 3

我创建了一个新项目，当我创建它时选择新的“选项卡式应用程序”。它提供了两个嵌入在一个标签栏控制器中的UIViewControllers。我试图在视图控制器之间传递两个变量。

问题是从不调用segue函数的准备。我在其中添加了一个永不打印的打印声明。我在两个视图控制器中添加了prepare函数，并且可以来回切换而不打印。

一些代码：

import UIKit
import MapKit
import CoreLocation

class FirstViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate{

@IBOutlet weak var mapView: MKMapView!
var locationManager:CLLocationManager?
var currentLocation:CLLocation?
var destPin: MapPin?
var isTracking: Bool? = false

override func viewDidLoad() {
    super.viewDidLoad()
    locationManager = CLLocationManager()
    locationManager?.delegate = self
    locationManager?.startUpdatingLocation()
    locationManager?.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
    locationManager?.requestAlwaysAuthorization()
    updateTracking()
}



func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    self.currentLocation = locations[0]
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
    print(error)
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}
func getMapView()-> MKMapView{
    return mapView
}
override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    if(self.isTracking!){
        print("Istracking bool is true")
    }
    else{
        print("Istracking bool is false")
    }
    updateTracking()
    locationManager?.stopUpdatingLocation()

}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    print("Preparing")

    let barViewControllers = segue.destination as! UITabBarController
    let destinationViewController = barViewControllers.viewControllers![1] as! FirstViewController
    destinationViewController.destPin = self.destPin
    destinationViewController.isTracking = self.isTracking
    }
}

准备功能的内容也可能是错误的，但即使被调用它也几乎不重要。另一个视图控制器也嵌入在选项卡栏控制器中，并且还具有不执行的准备功能。

如果您愿意，请参阅此github repo

Answer 1

很容易做到：

结果：

例如，FirstViewController中嵌入了SecondViewController和tabViewController：

在firstViewController.swift：

中

import UIKit

class FirstViewController: UIViewController {

    var vc1_variable:String = "first vc's variable."

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

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


}

在secondViewController.swift：

中

import UIKit

class SecondViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        let first_vc:FirstViewController = self.tabBarController?.viewControllers![0] as! FirstViewController

        print("\(first_vc.vc1_variable)")
    }
}