added in Watch Session and Crown support code

ios/WatchTips Extension/InterfaceController.swift

@@ -8,9 +8,10 @@
 
 import WatchKit
 import Foundation
+import WatchConnectivity
 
 
-class InterfaceController: WKInterfaceController, WKCrownDelegate {
+class InterfaceController: WKInterfaceController, WCSessionDelegate, WKCrownDelegate {
 
 
     var tipAmount: Int = 10
@@ -27,14 +28,55 @@ class InterfaceController: WKInterfaceController, WKCrownDelegate {
     @IBOutlet weak var withTip: WKInterfaceLabel!
 
 
+    public func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
+        // This will be called when the activation of a session finishes.
+    }
+
+
+
     func crownDidBecomeIdle(_ crownSequencer: WKCrownSequencer?) {
         accumulatedCrownDelta = 0.0
     }
 
     func crownDidRotate(_ crownSequencer: WKCrownSequencer?, rotationalDelta: Double) {
         accumulatedCrownDelta += rotationalDelta
-        //let threshoold = 0.5
+        let threshold = 0.05
+
+        // do nothing if delta is less that threshold
+        guard abs(accumulatedCrownDelta) > threshold else {
+            return
+        }
+
+        if focusButton == 1 {
+            if accumulatedCrownDelta > 0 {
+                splitBetween += 1
+            } else {
+                splitBetween -= 1
+            }
+            if splitBetween < 1 {
+                splitBetween = 1
+            }
+            if splitBetween > 50 {
+                splitBetween = 50
+            }
+        }
 
+        if focusButton == 2 {
+            if accumulatedCrownDelta > 0 {
+                tipAmount += 1
+            } else {
+                tipAmount -= 1
+            }
+            if tipAmount < 0 {
+                tipAmount = 0
+            }
+            if tipAmount > 100 {
+                tipAmount = 100
+            }
+        }
+
+        accumulatedCrownDelta = 0
+        updateCalc()
 
     }
 
@@ -50,7 +92,11 @@ class InterfaceController: WKInterfaceController, WKCrownDelegate {
     override func willActivate() {
         // This method is called when watch view controller is about to be visible to user
         super.willActivate()
-
+        if WCSession.isSupported() {
+            let session = WCSession.default
+            session.delegate = self
+            session.activate()
+        }
         crownSequencer.focus()
         updateCalc()
     }
@@ -63,19 +109,34 @@ class InterfaceController: WKInterfaceController, WKCrownDelegate {
 
     // chnage how many the bill is split between
     @IBAction func showSplitController() {
+        resetButtonFocus()
+        currentSplit?.setBackgroundColor(UIColor(red: 0/255, green: 128/255, blue: 255/255, alpha: 1.0))
+        focusButton = 1
         presentController(withName: "SplitController", context: self)
     }
 
 
     @IBAction func showTipController() {
+        resetButtonFocus()
+        currentTip?.setBackgroundColor(UIColor(red: 0/255, green: 128/255, blue: 255/255, alpha: 1.0))
+        focusButton = 2
         presentController(withName: "TipController", context: self)
     }
 
 
     @IBAction func showBillController() {
+        resetButtonFocus()
         presentController(withName: "BillController", context: self)
     }
 
+    // reset the focus to the currently selected button
+    func resetButtonFocus(){
+        focusButton = 0
+        currentSplit?.setBackgroundColor(UIColor.darkGray)
+        currentTip?.setBackgroundColor(UIColor.darkGray)
+        billButton?.setBackgroundColor(UIColor.darkGray)
+    }
+
     // Update the actual calculations
     func updateCalc(){
 
@@ -92,15 +153,15 @@ class InterfaceController: WKInterfaceController, WKCrownDelegate {
         costEach.setText(String(format: "%.2f", perPerson))
 
         // now see if we can sent the calc data back to the app
-        //if WCSession.isSupported() {
-        //    let session = WCSession.default()
-        //    let calcInfo = [
-        //        "tip":"\(tipAmount)",
-        //        "split": "\(splitBetween)",
-        //        "bill": "\(billTotal)"
-        //        ] as [String : Any];
-        //    session.transferUserInfo(calcInfo)
-        //}
+        if WCSession.isSupported() {
+            let session = WCSession.default
+            let calcInfo = [
+                "tip":"\(tipAmount)",
+                "split": "\(splitBetween)",
+                "bill": "\(billTotal)"
+                ] as [String : Any];
+            session.transferUserInfo(calcInfo)
+        }
     }