[view] add focus method

src/main/haxework/view/frame/FrameSwitcher.hx

@@ -58,10 +58,7 @@ class FrameSwitcher extends GroupView {
         addView(current);
         toUpdate();
         update();
-        //ToDo:
-        if (content.stage != null) {
-            content.stage.focus = current.content;
-        }
+        focus(current);
         current.onShow(data);
         if (animate != null) {
             animate.cancel();

src/main/haxework/view/group/GroupView.hx

@@ -67,7 +67,7 @@ class OverflowControl {
 }
 
 @:style(true) class GroupView extends SpriteView implements IGroupView {
-    public var container(null, null):DisplayObjectContainer;
+    public var container(default, null):DisplayObjectContainer;
 
     public var views(default, set):Array<IView<Dynamic>>;
     @:style public var layout(default, default):ILayout;
@@ -253,6 +253,12 @@ class OverflowControl {
         }
     }
 
+    public function focus(?view:IView<Dynamic>):Void {
+        if (container.stage != null) {
+            container.stage.focus = view != null ? view.content : content;
+        }
+    }
+
     override private function get_rect():Rectangle {
         var result = super.get_rect();
         result.x += overflowControlX.offset;

src/main/haxework/view/group/IGroupView.hx

@@ -11,7 +11,7 @@ interface IGroupView extends IView<Dynamic> {
     public var overflowX(default, set):Float;
     public var overflowY(default, set):Float;
 
-    public var container(null, null):DisplayObjectContainer;
+    public var container(default, null):DisplayObjectContainer;
     public var views(default, set):Array<IView<Dynamic>>;
 
     public function containsView(view:IView<Dynamic>):Bool;
@@ -25,4 +25,6 @@ interface IGroupView extends IView<Dynamic> {
     public function removeView(view:IView<Dynamic>):IView<Dynamic>;
 
     public function removeAllViews():Void;
+
+    public function focus(?view:IView<Dynamic>):Void;
 }

src/main/haxework/view/popup/PopupManager.hx

@@ -38,6 +38,7 @@ class PopupManager {
     public function remove(popup:P):Void {
         if (root.containsView(popup)) {
             root.removeView(popup);
+            root.focus();
         }
     }