Add backend framework for radio buttons in nativemenus.

native/Avalonia.Native/inc/avalonia-native.h

@@ -176,6 +176,13 @@ enum AvnWindowEdge
     WindowEdgeSouthEast
 };
 
+enum AvnMenuItemToggleType
+{
+    None,
+    CheckMark,
+    Radio
+};
+
 AVNCOM(IAvaloniaNativeFactory, 01) : IUnknown
 {
 public:
@@ -407,6 +414,7 @@ AVNCOM(IAvnMenuItem, 19) : IUnknown
     virtual HRESULT SetGesture (void* utf8String, AvnInputModifiers modifiers) = 0;
     virtual HRESULT SetAction (IAvnPredicateCallback* predicate, IAvnActionCallback* callback) = 0;
     virtual HRESULT SetIsChecked (bool isChecked) = 0;
+    virtual HRESULT SetToggleType (AvnMenuItemToggleType toggleType) = 0;
 };
 
 AVNCOM(IAvnMenuEvents, 1A) : IUnknown

native/Avalonia.Native/src/OSX/menu.h

@@ -32,6 +32,7 @@ private:
     IAvnActionCallback* _callback;
     IAvnPredicateCallback* _predicate;
     bool _isSeperator;
+    bool _isCheckable;
     
 public:
     FORWARD_IUNKNOWN()
@@ -50,6 +51,8 @@ public:
     
     virtual HRESULT SetIsChecked (bool isChecked) override;
     
+    virtual HRESULT SetToggleType (AvnMenuItemToggleType toggleType) override;
+    
     bool EvaluateItemEnabled();
     
     void RaiseOnClicked();

native/Avalonia.Native/src/OSX/menu.mm

@@ -70,6 +70,7 @@
 
 AvnAppMenuItem::AvnAppMenuItem(bool isSeperator)
 {
+    _isCheckable = false;
     _isSeperator = isSeperator;
     
     if(isSeperator)
@@ -157,7 +158,32 @@ HRESULT AvnAppMenuItem::SetIsChecked (bool isChecked)
 {
     @autoreleasepool
     {
-        [_native setState:(isChecked ? NSOnState : NSOffState)];
+        [_native setState:(isChecked && _isCheckable ? NSOnState : NSOffState)];
+        return S_OK;
+    }
+}
+
+HRESULT AvnAppMenuItem::SetToggleType(AvnMenuItemToggleType toggleType)
+{
+    @autoreleasepool
+    {
+        switch(toggleType)
+        {
+            case AvnMenuItemToggleType::None:
+                [_native setOnStateImage:nullptr];
+                _isCheckable = false;
+                break;
+                
+            case AvnMenuItemToggleType::CheckMark:
+                [_native setOnStateImage:nullptr];
+                _isCheckable = true;
+                break;
+                
+            case AvnMenuItemToggleType::Radio:
+                [_native setOnStateImage: [NSImage imageNamed:@"NSMenuRadio"]];
+                break;
+        }
+        
         return S_OK;
     }
 }

src/Avalonia.Native/IAvnMenuItem.cs

@@ -26,6 +26,11 @@ namespace Avalonia.Native.Interop
             IsChecked = isChecked;
         }
 
+        private void UpdateToggleType(NativeMenuItemToggleType toggleType)
+        {
+            
+        }
+
         private void UpdateGesture(Input.KeyGesture gesture)
         {
             // todo ensure backend can cope with setting null gesture.