From 926ee41277caf66cadfc62b1be202cb054f8280a Mon Sep 17 00:00:00 2001
From: Kyle Matthew Hedden <kyle.hedden@verizonwireless.com>
Date: Thu, 10 Mar 2022 21:43:54 -0500
Subject: [PATCH] will show and will hide

---
 MVMCoreUI/BaseControllers/ViewController.swift   | 16 ++++++++++++++++
 .../Protocols/PageBehaviorProtocol.swift         | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/MVMCoreUI/BaseControllers/ViewController.swift b/MVMCoreUI/BaseControllers/ViewController.swift
index b385ae29..2851b479 100644
--- a/MVMCoreUI/BaseControllers/ViewController.swift
+++ b/MVMCoreUI/BaseControllers/ViewController.swift
@@ -385,6 +385,14 @@ import UIKit
         }
     }
     
+    open override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        
+        executeBehaviors { [weak self] (behavior: PageVisibilityBehavior) in
+            behavior.willShowPage(self?.delegateObjectIVar)
+        }
+    }
+    
     open override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
         
@@ -393,6 +401,14 @@ import UIKit
         }
     }
     
+    open override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        
+        executeBehaviors { [weak self] (behavior: PageVisibilityBehavior) in
+            behavior.willHidePage(self?.delegateObjectIVar)
+        }
+    }
+    
     open override func viewDidDisappear(_ animated: Bool) {
         super.viewDidDisappear(animated)
         
diff --git a/MVMCoreUI/Behaviors/Protocols/PageBehaviorProtocol.swift b/MVMCoreUI/Behaviors/Protocols/PageBehaviorProtocol.swift
index 65773aa0..15b15d68 100644
--- a/MVMCoreUI/Behaviors/Protocols/PageBehaviorProtocol.swift
+++ b/MVMCoreUI/Behaviors/Protocols/PageBehaviorProtocol.swift
@@ -33,10 +33,20 @@ public extension PageMoleculeTransformationBehavior {
 
 public protocol PageVisibilityBehavior: PageBehaviorProtocol {
     
+    func willShowPage(_ delegateObject: MVMCoreUIDelegateObject?)
     func onPageShown(_ delegateObject: MVMCoreUIDelegateObject?)
+    func willHidePage(_ delegateObject: MVMCoreUIDelegateObject?)
     func onPageHidden(_ delegateObject: MVMCoreUIDelegateObject?)
 }
 
+public extension PageVisibilityBehavior {
+    // All optional.
+    func willShowPage(_ delegateObject: MVMCoreUIDelegateObject?) {}
+    func onPageShown(_ delegateObject: MVMCoreUIDelegateObject?) {}
+    func willHidePage(_ delegateObject: MVMCoreUIDelegateObject?) {}
+    func onPageHidden(_ delegateObject: MVMCoreUIDelegateObject?) {}
+}
+
 public protocol PageScrolledBehavior: PageBehaviorProtocol {
     
     func pageScrolled(scrollView: UIScrollView, _ delegateObject: MVMCoreUIDelegateObject?)