From 18c2f2c5d54650491c7ea8a06553ecd43241edc5 Mon Sep 17 00:00:00 2001
From: Steve Streeting <steve@stevestreeting.com>
Date: Fri, 7 Jan 2022 16:10:48 +0000
Subject: [PATCH] Oops, missed added files

---
 .../Public/StevesUiHelpers.cpp                | 44 +++++++++++++++++++
 .../StevesUEHelpers/Public/StevesUiHelpers.h  | 17 +++++++
 2 files changed, 61 insertions(+)
 create mode 100644 Source/StevesUEHelpers/Public/StevesUiHelpers.cpp
 create mode 100644 Source/StevesUEHelpers/Public/StevesUiHelpers.h

diff --git a/Source/StevesUEHelpers/Public/StevesUiHelpers.cpp b/Source/StevesUEHelpers/Public/StevesUiHelpers.cpp
new file mode 100644
index 0000000..1d96d56
--- /dev/null
+++ b/Source/StevesUEHelpers/Public/StevesUiHelpers.cpp
@@ -0,0 +1,44 @@
+#include "StevesUiHelpers.h"
+
+#include "Components/PanelWidget.h"
+
+void StevesUiHelpers::InsertChildWidgetAt(UPanelWidget* Parent, UWidget* Child, int AtIndex)
+{
+	checkf(AtIndex <= Parent->GetChildrenCount(), TEXT("Insertion index %d is greater than child count"), AtIndex);
+	
+	// Short-circuit for simple case of insert at end
+	const int OrigCount = Parent->GetChildrenCount();
+	if (OrigCount == AtIndex)
+	{
+		Parent->AddChild(Child);
+	}
+	else
+	{
+		// Note: cannot use InsertChildAt, that's editor-only
+		// There are a few options with the runtime API
+		// 1. Remove all children and re-add them in the right order
+		// 2. Remove all children on or after the insert point and re-add those after adding the new item
+		// 3. Use ReplaceChildAt to insert a new item and move everything down, with AddChild at the end
+		//
+		// I'm going with 2. because that seems to blend best performance with the most well defined behaviour
+		// I'm not sure ReplaceChildAt is designed to move children around (note: ShiftChild exists but again, editor-only)
+
+		TArray<UWidget*> WidgetsToReplaceReversed;
+		WidgetsToReplaceReversed.Reserve(OrigCount - AtIndex);
+		// Go backwards so we can remove as we go and not remove from the middle
+		for (int i = OrigCount - 1; i >= AtIndex; --i)
+		{
+			WidgetsToReplaceReversed.Add(Parent->GetChildAt(i));
+			Parent->RemoveChildAt(i);
+		}
+		// insert item
+		Parent->AddChild(Child);
+		// add back previous, reverse order
+		for (int i = WidgetsToReplaceReversed.Num()  - 1; i >= 0; --i)
+		{
+			Parent->AddChild(WidgetsToReplaceReversed[i]);
+		}
+		
+	}
+	
+}
diff --git a/Source/StevesUEHelpers/Public/StevesUiHelpers.h b/Source/StevesUEHelpers/Public/StevesUiHelpers.h
new file mode 100644
index 0000000..aa9ab4b
--- /dev/null
+++ b/Source/StevesUEHelpers/Public/StevesUiHelpers.h
@@ -0,0 +1,17 @@
+#pragma once
+#include "CoreMinimal.h"
+#include "Components/Widget.h"
+
+/// Helper Ui routines that UE4 is missing, all static
+/// Exposed to BP in in StevesBPL
+class STEVESUEHELPERS_API StevesUiHelpers
+{
+public:
+	/**
+	 * Insert a child widget at a specific index
+	 * @param Parent The container widget
+	 * @param Child The child widget to add
+	 * @param AtIndex The index at which the new child should exist
+	 */
+	static void InsertChildWidgetAt(UPanelWidget* Parent, UWidget* Child, int AtIndex = 0);
+};