Added previous code with ifdef

Author: MarcShakour

Assets/FbxExporters/Editor/ConvertToPrefabEditorWindow.cs

@@ -3,6 +3,9 @@
 using UnityEngine;
 using UnityEditor;
 using FbxExporters.EditorTools;
+#if UNITY_2018_1_OR_NEWER
+using UnityEditor.Presets;
+#endif
 using System.Linq;
 
 namespace FbxExporters
@@ -83,7 +86,12 @@ protected override bool DisableNameSelection ()
             {
                 return m_toConvert.Length > 1;
             }
-
+            #if UNITY_2018_1_OR_NEWER
+            protected override void ShowPresetReceiver ()
+            {
+                ShowPresetReceiver (ExportSettings.instance.convertToPrefabSettings);
+            }
+            #endif
             protected override void CreateCustomUI ()
             {
                 GUILayout.BeginHorizontal ();

Assets/FbxExporters/Editor/ExportModelEditorWindow.cs

@@ -3,6 +3,9 @@
 using UnityEngine;
 using UnityEditor;
 using FbxExporters.EditorTools;
+#if UNITY_2018_1_OR_NEWER
+using UnityEditor.Presets;
+#endif
 using System.Linq;
 
 namespace FbxExporters
@@ -28,6 +31,11 @@ public abstract class ExportOptionsEditorWindow : EditorWindow
             protected string m_exportFileName = "";
 
             protected UnityEditor.Editor m_innerEditor;
+            #if UNITY_2018_1_OR_NEWER
+            protected FbxExportPresetSelectorReceiver m_receiver;
+            #endif
+            private static GUIContent presetIcon { get { return EditorGUIUtility.IconContent ("Preset.Context"); }}
+            private static GUIStyle presetIconButton { get { return new GUIStyle("IconButton"); }}
 
             private bool m_showOptions;
 
@@ -36,6 +44,9 @@ public abstract class ExportOptionsEditorWindow : EditorWindow
             protected float m_fbxExtLabelWidth;
 
             protected virtual void OnEnable(){
+                #if UNITY_2018_1_OR_NEWER
+                InitializeReceiver ();
+                #endif
                 m_showOptions = true;
                 this.minSize = new Vector2 (SelectableLabelMinWidth + LabelWidth + BrowseButtonWidth, MinWindowHeight);
 
@@ -60,6 +71,18 @@ protected virtual void InitializeWindow(string filename = ""){
                 this.SetFilename (filename);
             }
 
+            #if UNITY_2018_1_OR_NEWER
+            protected void InitializeReceiver(){
+                if (!m_receiver) {
+                    m_receiver = ScriptableObject.CreateInstance<FbxExportPresetSelectorReceiver> () as FbxExportPresetSelectorReceiver;
+                    m_receiver.SelectionChanged -= OnPresetSelectionChanged;
+                    m_receiver.SelectionChanged += OnPresetSelectionChanged;
+                    m_receiver.DialogClosed -= SaveExportSettings;
+                    m_receiver.DialogClosed += SaveExportSettings;
+                }
+            }
+            #endif
+
             public void SetFilename(string filename){
                 // remove .fbx from end of filename
                 int extIndex = filename.LastIndexOf(".fbx");
@@ -93,13 +116,31 @@ protected virtual bool DisableNameSelection(){
                 return false;
             }
 
+            #if UNITY_2018_1_OR_NEWER  
+            protected abstract void ShowPresetReceiver ();
+
+            protected void ShowPresetReceiver(UnityEngine.Object target){
+                InitializeReceiver ();
+                m_receiver.SetTarget(target);
+                m_receiver.SetInitialValue (new Preset (target));
+                UnityEditor.Presets.PresetSelector.ShowSelector(target, null, true, m_receiver);
+            }
+            #endif
+
             protected void OnGUI ()
             {
                 // Increasing the label width so that none of the text gets cut off
                 EditorGUIUtility.labelWidth = LabelWidth;
 
                 GUILayout.BeginHorizontal ();
                 GUILayout.FlexibleSpace ();
+                
+                #if UNITY_2018_1_OR_NEWER  
+                if(EditorGUILayout.DropdownButton(presetIcon, FocusType.Keyboard, presetIconButton)){
+                    ShowPresetReceiver ();
+                }
+                #endif
+
                 GUILayout.EndHorizontal();
 
                 EditorGUILayout.LabelField("Naming");
@@ -334,6 +375,13 @@ protected override void Export(){
                     AssetDatabase.Refresh ();
                 }
             }
+
+            #if UNITY_2018_1_OR_NEWER  
+            protected override void ShowPresetReceiver ()
+            {
+                ShowPresetReceiver (ExportSettings.instance.exportModelSettings);
+            }
+            #endif
         }
     }
 }

Assets/FbxExporters/Editor/FbxExportPresetSelectorReceiver.cs

@@ -0,0 +1,50 @@
+#if UNITY_2018_1_OR_NEWER
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEditor.Presets;
+
+public class FbxExportPresetSelectorReceiver : PresetSelectorReceiver
+{
+    UnityEngine.Object m_Target;
+    Preset m_InitialValue;
+
+    public delegate void SelectionChangedDelegate();
+    public event SelectionChangedDelegate SelectionChanged;
+
+    public delegate void DialogClosedDelegate();
+    public event DialogClosedDelegate DialogClosed;
+
+    public override void OnSelectionClosed(Preset selection)
+    {
+        OnSelectionChanged(selection);
+        if (DialogClosed != null) {
+            DialogClosed ();
+        }
+        DestroyImmediate(this);
+    }
+
+    public override void OnSelectionChanged(Preset selection)
+    {
+        if (selection != null)
+        {
+            selection.ApplyTo(m_Target);
+        }
+        else
+        {
+            m_InitialValue.ApplyTo(m_Target);
+        }
+        if (SelectionChanged != null) {
+            SelectionChanged ();
+        }
+    }
+
+    public void SetTarget(UnityEngine.Object target){
+        m_Target = target;
+    }
+
+    public void SetInitialValue(Preset initialValue){
+        m_InitialValue = initialValue;
+    }
+}
+#endif