LCL-CustomDrawn-Win: Implements GetAppHandle which fixes the showing of the taskbar

git-svn-id: trunk@36161 -

lcl/interfaces/customdrawn/customdrawnint.pas

@@ -217,8 +217,8 @@ type
   //
   protected
     {function CreateThemeServices: TThemeServices; override;}
-    {function GetAppHandle: THandle; override;
+    function GetAppHandle: THandle; override; //BackendSpecific
-    procedure SetAppHandle(const AValue: THandle); override;}
+    //procedure SetAppHandle(const AValue: THandle); override;
     //
     procedure BackendCreate;
     procedure BackendDestroy;

lcl/interfaces/customdrawn/customdrawnobject_android.inc

@@ -720,6 +720,11 @@ begin
   end;
 end;
 
+function TCDWidgetSet.GetAppHandle: THandle;
+begin
+  Result := 0;
+end;
+
 {------------------------------------------------------------------------------
   Method: TCDWidgetSet.Create
   Params:  None

lcl/interfaces/customdrawn/customdrawnobject_cocoa.inc

@@ -24,6 +24,11 @@
 
 { TCDWidgetSet }
 
+function TCDWidgetSet.GetAppHandle: THandle; override;
+begin
+  Result := THandle(NSApp);
+end;
+
 {------------------------------------------------------------------------------
   Method:  TCDWidgetSet.AppInit
   Params:  ScreenInfo

lcl/interfaces/customdrawn/customdrawnobject_win.inc

@@ -85,6 +85,11 @@ begin
   {$endif}
 end;
 
+function TCDWidgetSet.GetAppHandle: THandle;
+begin
+  Result := FAppHandle;
+end;
+
 {------------------------------------------------------------------------------
   Method: TCDWidgetSet.Create
   Params:  None

lcl/interfaces/customdrawn/customdrawnobject_x11.inc

@@ -423,6 +423,11 @@ begin
   end;
 end;
 
+function TCDWidgetSet.GetAppHandle: THandle;
+begin
+  Result := THandle(FDisplay);
+end;
+
 (*
 procedure TWinCEWidgetSet.CheckPipeEvents;
 var

lcl/interfaces/customdrawn/customdrawnwsforms_win.inc

@@ -624,13 +624,38 @@ end;
 
 class procedure TCDWSCustomForm.SetShowInTaskbar(const AForm: TCustomForm;
   const AValue: TShowInTaskbar);
+var
+  OldStyle, NewStyle: DWord;
+  Visible, Active: Boolean;
 begin
   if not WSCheckHandleAllocated(AForm, 'SetShowInTaskbar') then
     Exit;
-  if (Application <> nil) and (AForm = Application.MainForm) then
+  if Assigned(Application) and (AForm = Application.MainForm) then
     Exit;
 
-  RecreateWnd(AForm);
+  OldStyle := GetWindowLong(AForm.Handle, GWL_EXSTYLE);
+  NewStyle := OldStyle;
+  if AValue = stAlways then
+    NewStyle := NewStyle or WS_EX_APPWINDOW
+  else
+    NewStyle := NewStyle and not WS_EX_APPWINDOW;
+  if OldStyle = NewStyle then exit;
+
+  // to apply this changes we need either to hide window or recreate it. Hide is
+  // less difficult
+  Visible := IsWindowVisible(AForm.Handle);
+  Active := GetForegroundWindow = AForm.Handle;
+  if Visible then
+    ShowWindow(AForm.Handle, SW_HIDE);
+
+  SetWindowLong(AForm.Handle, GWL_EXSTYLE, NewStyle);
+
+  // now we need to restore window visibility with saving focus
+  if Visible then
+    if Active then
+      ShowWindow(AForm.Handle, SW_SHOW)
+    else
+      ShowWindow(AForm.Handle, SW_SHOWNA);
 end;
 
 class procedure TCDWSCustomForm.ShowModal(const ACustomForm: TCustomForm);