Commit

Carthage/Checkouts/TrueTime.swift/Examples/iOS/ViewController.swift

@@ -0,0 +1,98 @@
+//
+//  ViewController.swift
+//  TrueTime
+//
+//  Created by Michael Sanders on 10/26/16.
+//  Copyright © 2016 Instacart. All rights reserved.
+//
+
+import UIKit
+import TrueTime
+
+final class ExampleViewController: UIViewController {
+    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
+        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(startTimer),
+            name: UIApplication.didBecomeActiveNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(cancelTimer),
+            name: UIApplication.willResignActiveNotification,
+            object: nil
+        )
+    }
+
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    deinit {
+        NotificationCenter.default.removeObserver(self)
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        label.frame = view.bounds.insetBy(dx: 15, dy: 15)
+        label.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+        view.addSubview(label)
+    }
+
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        refresh()
+        startTimer()
+
+    }
+
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        cancelTimer()
+    }
+
+    fileprivate var referenceTime: ReferenceTime?
+    fileprivate var timer: Timer?
+    fileprivate lazy var label: UILabel = {
+        let label = UILabel()
+        label.textColor = .black
+        label.textAlignment = .center
+        label.font = .systemFont(ofSize: 14)
+        label.numberOfLines = 0
+        return label
+    }()
+}
+
+private extension ExampleViewController {
+    @objc func startTimer() {
+        timer = .scheduledTimer(withTimeInterval: 0.5, repeats: true) { [weak self] _ in
+            self?.tick()
+        }
+    }
+
+    @objc func cancelTimer() {
+        timer?.invalidate()
+        timer = nil
+    }
+
+    func tick() {
+        if let referenceTime = referenceTime {
+            let trueTime = referenceTime.now()
+            label.text = "\(trueTime)\n\n\(referenceTime)"
+        }
+    }
+
+    func refresh() {
+        TrueTimeClient.sharedInstance.fetchIfNeeded { result in
+            switch result {
+            case let .success(referenceTime):
+                self.referenceTime = referenceTime
+                print("Got network time! \(referenceTime)")
+            case let .failure(error):
+                print("Error! \(error)")
+            }
+        }
+    }
+}