From d4bace023aeb58a601c63ea1e31f9548b1213475 Mon Sep 17 00:00:00 2001
From: Li <ldmorrow@outlook.com>
Date: Mon, 1 Jul 2024 22:51:25 +1000
Subject: [PATCH] Fix issue where android keyboard covers input

---
 LiftLog.App/Platforms/Android/MainActivity.cs | 26 +++++-
 .../Android/WebViewSoftInputPatch.cs          | 86 +++++++++++++++++++
 2 files changed, 108 insertions(+), 4 deletions(-)
 create mode 100644 LiftLog.App/Platforms/Android/WebViewSoftInputPatch.cs

diff --git a/LiftLog.App/Platforms/Android/MainActivity.cs b/LiftLog.App/Platforms/Android/MainActivity.cs
index 14729987..17bc0d48 100644
--- a/LiftLog.App/Platforms/Android/MainActivity.cs
+++ b/LiftLog.App/Platforms/Android/MainActivity.cs
@@ -41,12 +41,20 @@ protected override void OnCreate(Bundle? savedInstanceState)
     {
         base.OnCreate(savedInstanceState);
         WindowCompat.SetDecorFitsSystemWindows(Window!, false);
+        WebViewSoftInputPatch.Initialize();
         var insetsManager =
             IPlatformApplication.Current?.Services.GetRequiredService<InsetsManager>();
-        ViewCompat.SetOnApplyWindowInsetsListener(
-            Window!.DecorView,
-            new WindowInsetsListener(insetsManager!, Resources!.DisplayMetrics!.Density)
-        );
+        if (insetsManager is not null)
+        {
+            insetsManager.SystemSafeInsetBottom =
+                $"{WebViewSoftInputPatch.GetNavBarHeight() / Resources!.DisplayMetrics!.Density}px";
+            insetsManager.SystemSafeInsetTop =
+                $"{WebViewSoftInputPatch.GetStatusBarHeight() / Resources.DisplayMetrics.Density}px";
+            ViewCompat.SetOnApplyWindowInsetsListener(
+                Window!.DecorView,
+                new WindowInsetsListener(insetsManager!, Resources.DisplayMetrics.Density)
+            );
+        }
     }
 
     private class WindowInsetsListener(InsetsManager insetsManager, float density)
@@ -59,8 +67,18 @@ WindowInsetsCompat insets
         )
         {
             // convert android px to css px
+
             var top = insets.SystemWindowInsetTop / density;
             var bottom = insets.SystemWindowInsetBottom / density;
+            if (top == 0 || bottom == 0)
+            {
+                insetsManager.SystemSafeInsetBottom =
+                    $"{WebViewSoftInputPatch.GetNavBarHeight() / density}px";
+                insetsManager.SystemSafeInsetTop =
+                    $"{WebViewSoftInputPatch.GetStatusBarHeight() / density}px";
+                insetsManager.NotifyInsetsChanged();
+                return insets;
+            }
             insetsManager.SystemSafeInsetTop = $"{top}px";
             insetsManager.SystemSafeInsetBottom = $"{bottom}px";
             insetsManager.NotifyInsetsChanged();
diff --git a/LiftLog.App/Platforms/Android/WebViewSoftInputPatch.cs b/LiftLog.App/Platforms/Android/WebViewSoftInputPatch.cs
new file mode 100644
index 00000000..980ffb32
--- /dev/null
+++ b/LiftLog.App/Platforms/Android/WebViewSoftInputPatch.cs
@@ -0,0 +1,86 @@
+using System.Runtime.Versioning;
+using Android.Content.Res;
+using Android.Views;
+using Android.Widget;
+using static Android.Resource;
+using Activity = Android.App.Activity;
+using Rect = Android.Graphics.Rect;
+using View = Android.Views.View;
+
+namespace LiftLog.App;
+
+[SupportedOSPlatform("Android")]
+public static class WebViewSoftInputPatch
+{
+    static Activity Activity =>
+        Microsoft.Maui.ApplicationModel.Platform.CurrentActivity
+        ?? throw new InvalidOperationException("Android Activity can't be null.");
+    static View MChildOfContent;
+    static FrameLayout.LayoutParams FrameLayoutParams;
+    static int UsableHeightPrevious = 0;
+
+    public static void Initialize()
+    {
+        FrameLayout content = (FrameLayout)Activity.FindViewById(Id.Content);
+        MChildOfContent = content.GetChildAt(0);
+        MChildOfContent.ViewTreeObserver.GlobalLayout += (s, o) => PossiblyResizeChildOfContent();
+        FrameLayoutParams = (FrameLayout.LayoutParams)MChildOfContent?.LayoutParameters;
+    }
+
+    static void PossiblyResizeChildOfContent()
+    {
+        int usableHeightNow = ComputeUsableHeight();
+        if (usableHeightNow != UsableHeightPrevious)
+        {
+            int usableHeightSansKeyboard = MChildOfContent.RootView.Height;
+            int heightDifference = usableHeightSansKeyboard - usableHeightNow;
+            if (heightDifference < 0)
+            {
+                usableHeightSansKeyboard = MChildOfContent.RootView.Width;
+                heightDifference = usableHeightSansKeyboard - usableHeightNow;
+            }
+
+            if (heightDifference > usableHeightSansKeyboard / 4)
+            {
+                FrameLayoutParams.Height = usableHeightSansKeyboard - heightDifference;
+            }
+            else
+            {
+                FrameLayoutParams.Height = usableHeightNow;
+            }
+        }
+
+        MChildOfContent.RequestLayout();
+        UsableHeightPrevious = usableHeightNow;
+    }
+
+    static int ComputeUsableHeight()
+    {
+        Rect rect = new Rect();
+        MChildOfContent.GetWindowVisibleDisplayFrame(rect);
+        return rect.Bottom + GetNavBarHeight();
+    }
+
+    public static int GetNavBarHeight()
+    {
+        int result = 0;
+        Resources resources = Activity.Resources;
+        int resourceId = resources.GetIdentifier("navigation_bar_height", "dimen", "android");
+        if (resourceId > 0)
+        {
+            result = resources.GetDimensionPixelSize(resourceId);
+        }
+        return result;
+    }
+
+    public static int GetStatusBarHeight()
+    {
+        int result = 0;
+        int resourceId = Activity.Resources.GetIdentifier("status_bar_height", "dimen", "android");
+        if (resourceId > 0)
+        {
+            result = Activity.Resources.GetDimensionPixelSize(resourceId);
+        }
+        return result;
+    }
+}