From ca4c8731bc21117efdc938df63fcc07fa97aa2b0 Mon Sep 17 00:00:00 2001
From: Ellpeck <megamaximal@gmail.com>
Date: Wed, 24 Jun 2020 16:54:23 +0200
Subject: [PATCH] only throw an exception in TextInputWrapper if it is required

---
 MLEM.Ui/Elements/Element.cs   |  2 ++
 MLEM.Ui/Elements/TextField.cs |  1 +
 MLEM.Ui/UiSystem.cs           |  3 ++-
 MLEM/Misc/TextInputWrapper.cs | 17 +++++++++--------
 4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/MLEM.Ui/Elements/Element.cs b/MLEM.Ui/Elements/Element.cs
index d29e0c4..645cc08 100644
--- a/MLEM.Ui/Elements/Element.cs
+++ b/MLEM.Ui/Elements/Element.cs
@@ -313,6 +313,8 @@ namespace MLEM.Ui.Elements {
         public GenericCallback OnTouchExit;
         /// <summary>
         /// Event that is called when text input is made.
+        /// When an element uses this event, it should call <see cref="TextInputWrapper.EnsureExists"/> on construction to ensure that a text input wrapper was set.
+        ///
         /// Note that this event is called for every element, even if it is not selected.
         /// Also note that if <see cref="TextInputWrapper.RequiresOnScreenKeyboard"/> is true, this event is never called.
         /// </summary>
diff --git a/MLEM.Ui/Elements/TextField.cs b/MLEM.Ui/Elements/TextField.cs
index 1330fdb..4176ed0 100644
--- a/MLEM.Ui/Elements/TextField.cs
+++ b/MLEM.Ui/Elements/TextField.cs
@@ -132,6 +132,7 @@ namespace MLEM.Ui.Elements {
             if (font != null)
                 this.Font.Set(font);
 
+            TextInputWrapper.EnsureExists();
             if (TextInputWrapper.Current.RequiresOnScreenKeyboard()) {
                 this.OnPressed += async e => {
                     if (!KeyboardInput.IsVisible) {
diff --git a/MLEM.Ui/UiSystem.cs b/MLEM.Ui/UiSystem.cs
index 37e88c4..2754393 100644
--- a/MLEM.Ui/UiSystem.cs
+++ b/MLEM.Ui/UiSystem.cs
@@ -199,7 +199,8 @@ namespace MLEM.Ui {
                     root.Element.ForceUpdateArea();
             };
 
-            TextInputWrapper.Current.AddListener(window, (sender, key, character) => this.ApplyToAll(e => e.OnTextInput?.Invoke(e, key, character)));
+            if (TextInputWrapper.Current != null)
+                TextInputWrapper.Current.AddListener(window, (sender, key, character) => this.ApplyToAll(e => e.OnTextInput?.Invoke(e, key, character)));
             this.OnMousedElementChanged = e => this.ApplyToAll(t => t.OnMousedElementChanged?.Invoke(t, e));
             this.OnTouchedElementChanged = e => this.ApplyToAll(t => t.OnTouchedElementChanged?.Invoke(t, e));
             this.OnSelectedElementChanged = e => this.ApplyToAll(t => t.OnSelectedElementChanged?.Invoke(t, e));
diff --git a/MLEM/Misc/TextInputWrapper.cs b/MLEM/Misc/TextInputWrapper.cs
index e9bade5..e3fb4a8 100644
--- a/MLEM/Misc/TextInputWrapper.cs
+++ b/MLEM/Misc/TextInputWrapper.cs
@@ -13,19 +13,20 @@ namespace MLEM.Misc {
     /// </summary>
     public abstract class TextInputWrapper {
 
-        private static TextInputWrapper current;
         /// <summary>
         /// The current text input wrapper.
         /// Set this value before starting your game if you want to use text input wrapping.
         /// </summary>
         /// <exception cref="InvalidOperationException"></exception>
-        public static TextInputWrapper Current {
-            get {
-                if (current == null)
-                    throw new InvalidOperationException("The TextInputWrapper was not initialized. For more information, see https://mlem.ellpeck.de/articles/ui.html#text-input");
-                return current;
-            }
-            set => current = value;
+        public static TextInputWrapper Current;
+
+        /// <summary>
+        /// Ensures that <see cref="Current"/> is set to a valid <see cref="TextInputWrapper"/> value by throwing an <see cref="InvalidOperationException"/> exception if <see cref="Current"/> is null.
+        /// </summary>
+        /// <exception cref="InvalidOperationException">If <see cref="Current"/> is null</exception>
+        public static void EnsureExists() {
+            if (Current == null)
+                throw new InvalidOperationException("The TextInputWrapper was not initialized. For more information, see https://mlem.ellpeck.de/articles/ui.html#text-input");
         }
 
         /// <summary>