add PerScreen.IsActiveForScreen()

docs/release-notes.md

@@ -13,6 +13,9 @@
   * Updated to [FluentHttpClient](https://github.com/Pathoschild/FluentHttpClient#readme) 4.3.0 (see [changes](https://github.com/Pathoschild/FluentHttpClient/blob/develop/RELEASE-NOTES.md#430)).
   * Removed `LargeAddressAware` flag on SMAPI (no longer needed since it's 64-bit now).
 
+* For mod authors:
+  * Added `IsActiveForScreen()` method to `PerScreen<T>`.
+
 ## 3.18.2
 Released 09 January 2023 for Stardew Valley 1.5.6 or later.
 

src/SMAPI/Utilities/PerScreen.cs

@@ -101,6 +101,12 @@ namespace StardewModdingAPI.Utilities
             this.RemoveScreens(_ => true);
         }
 
+        /// <summary>Get whether the current screen has a value created yet.</summary>
+        public bool IsActiveForScreen()
+        {
+            return this.States.ContainsKey(Context.ScreenId);
+        }
+
 
         /*********
         ** Private methods