Extend logging of page lifecycle events to better analyse behaviour o…

…n iOS and Android.
zauberzeug · Jun 11, 2021 · a91842b · a91842b
1 parent 85d8425
commit a91842b
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Showing 7 changed files with 48 additions and 36 deletions.
diff --git a/DemoApp/App.cs b/DemoApp/App.cs
@@ -23,12 +23,12 @@ public App()
         public void ToggleFlyout()
         {
             if (MainPage is FlyoutPage)
-                MainPage = new NavigationPage(new NavigationDemoPage());
+                MainPage = new NavigationPage(new NavigationDemoPage()).AddPageLog();
             else
                 MainPage = new FlyoutPage {
                     Flyout = new MenuPage(),
-                    Detail = new NavigationPage(new NavigationDemoPage()),
-                };
+                    Detail = new NavigationPage(new NavigationDemoPage()).AddPageLog(),
+                }.AddPageLog();
         }
 
         public static void ShowMessage(string title, string message)

diff --git a/DemoApp/DemoApp.projitems b/DemoApp/DemoApp.projitems
@@ -44,6 +44,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)DemoPages\TitleViewPage.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)DemoPages\TabbedTitleViewPage.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)DemoPages\PopupDemoPage.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)PageExtensions.cs" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="$(MSBuildThisFileDirectory)DemoPages\" />

diff --git a/DemoApp/DemoPages/NavigationDemoPage.cs b/DemoApp/DemoPages/NavigationDemoPage.cs
@@ -8,6 +8,7 @@ public class NavigationDemoPage : ContentPage
         public NavigationDemoPage(string title = "Navigation")
         {
             Title = title;
+            PageExtensions.AddPageLog(this);
 
             Content = new StackLayout {
                 VerticalOptions = LayoutOptions.CenterAndExpand,
@@ -30,7 +31,7 @@ public NavigationDemoPage(string title = "Navigation")
                         Command = new Command(obj => Navigation.PopModalAsync()),
                     },
                     new DemoButton("PushModalAsync NavigationPage") {
-                        Command = new Command(o => Navigation.PushModalAsync(new NavigationPage(new NavigationDemoPage(title + " ^")))),
+                        Command = new Command(o => Navigation.PushModalAsync(new NavigationPage(new NavigationDemoPage(title + " ^")).AddPageLog())),
                     },
                     new DemoLabel("Flyout:"),
                     new DemoButton("Toggle Flyout MainPage") {
@@ -46,20 +47,6 @@ public NavigationDemoPage(string title = "Navigation")
                 (Content as StackLayout).Children.Insert(0, new DemoLabel("Title: " + title));
         }
 
-        protected override void OnAppearing()
-        {
-            base.OnAppearing();
-
-            App.PageLog += $"A({Title}) ";
-        }
-
-        protected override void OnDisappearing()
-        {
-            App.PageLog += $"D({Title}) ";
-
-            base.OnDisappearing();
-        }
-
         async void ShowAlert()
         {
             await DisplayAlert("Alert title", "Alert message", "Ok");

diff --git a/DemoApp/DemoPages/TabbedPageDemoPage.cs b/DemoApp/DemoPages/TabbedPageDemoPage.cs
@@ -7,9 +7,7 @@ public class TabbedPageDemoPage : TabbedPage
         public TabbedPageDemoPage()
         {
             Title = "TabbedPage";
-
-            Appearing += (s, e) => App.PageLog += $"A({Title}) ";
-            Disappearing += (s, e) => App.PageLog += $"D({Title}) ";
+            PageExtensions.AddPageLog(this);
 
             var contentPageA = new ContentPage {
                 Title = "Tab A",
@@ -20,9 +18,7 @@ public TabbedPageDemoPage()
                         new Button{Text = "Open Subpage", Command = new Command(OpenSubpage)},
                     }
                 }
-            };
-            contentPageA.Appearing += (s, e) => App.PageLog += $"A(Tab A) ";
-            contentPageA.Disappearing += (s, e) => App.PageLog += $"D(Tab A) ";
+            }.AddPageLog();
 
             var contentPageB = new ContentPage {
                 Title = "Tab B",
@@ -32,9 +28,7 @@ public TabbedPageDemoPage()
                     },
                 },
                 ToolbarItems = { new DemoToolbarItem() }
-            };
-            contentPageB.Appearing += (s, e) => App.PageLog += $"A(Tab B) ";
-            contentPageB.Disappearing += (s, e) => App.PageLog += $"D(Tab B) ";
+            }.AddPageLog();
 
             Children.Add(contentPageA);
             Children.Add(contentPageB);
@@ -43,30 +37,27 @@ public TabbedPageDemoPage()
         async void OpenModalPage()
         {
             var page = new ContentPage {
+                Title = "Modal",
                 Content = new StackLayout {
                     Children = {
                         new Label{Text = "This is a modal page"},
                         new Button{Text = "Close", Command = new Command(() => Navigation.PopModalAsync())},
                     }
                 }
-            };
-            page.Appearing += (s, e) => App.PageLog += $"A(Modal) ";
-            page.Disappearing += (s, e) => App.PageLog += $"D(Modal) ";
+            }.AddPageLog();
             await Navigation.PushModalAsync(page);
         }
 
         async void OpenSubpage()
         {
             var page = new ContentPage {
-                Title = "Some Subpage",
+                Title = "Subpage",
                 Content = new StackLayout {
                     Children = {
                         new Label{Text = "This is a sub page"},
                     }
                 }
-            };
-            page.Appearing += (s, e) => App.PageLog += $"A(Subpage) ";
-            page.Disappearing += (s, e) => App.PageLog += $"D(Subpage) ";
+            }.AddPageLog();
             await Navigation.PushAsync(page);
         }
     }

diff --git a/DemoApp/MenuPage.cs b/DemoApp/MenuPage.cs
@@ -47,7 +47,7 @@ DemoButton CreateMenuButton(string title, Func<Page> pageCreator)
             return new DemoButton(title) {
                 Command = new Command(o => {
                     var mainPage = (Application.Current.MainPage as FlyoutPage);
-                    mainPage.Detail = new NavigationPage(pageCreator.Invoke());
+                    mainPage.Detail = new NavigationPage(pageCreator.Invoke()).AddPageLog();
                     mainPage.IsPresented = false;
                 }),
             };

diff --git a/DemoApp/PageExtensions.cs b/DemoApp/PageExtensions.cs
@@ -0,0 +1,33 @@
+using System;
+using Xamarin.Forms;
+
+namespace DemoApp
+{
+    public static class PageExtensions
+    {
+        public static T AddPageLog<T>(this T page) where T : Page
+        {
+            page.Appearing += OnAppearing;
+            page.Disappearing += OnDisappearing;
+            return page;
+        }
+
+        static void OnAppearing(object sender, EventArgs e)
+        {
+            var page = sender as Page;
+            var logMessage = $"A({GetLogName(page)})";
+            App.PageLog += $"{logMessage} ";
+            Console.WriteLine(logMessage);
+        }
+
+        static void OnDisappearing(object sender, EventArgs e)
+        {
+            var page = sender as Page;
+            var logMessage = $"D({GetLogName(page)})";
+            App.PageLog += $"{logMessage} ";
+            Console.WriteLine(logMessage);
+        }
+
+        static string GetLogName(Page page) => page.Title ?? page.GetType().Name;
+    }
+}
diff --git a/Tests/NavigationTests.cs b/Tests/NavigationTests.cs
@@ -162,7 +162,7 @@ public void TestModalPopToRootEvent()
             var expectedLog = "A(Navigation) ";
 
             Tap("PushModalAsync NavigationPage");
-            Assert.That(App.PageLog, Is.EqualTo(expectedLog += "D(Navigation) A(Navigation ^) "));
+            Assert.That(App.PageLog, Is.EqualTo(expectedLog += "D(Navigation) A(NavigationPage) A(Navigation ^) "));
 
             Tap("PushAsync");
             Assert.That(App.PageLog, Is.EqualTo(expectedLog += "D(Navigation ^) A(Navigation ^ >) "));