feat: add support to display menu item opened on component rendering

Close #41

Author: Felipe Lang

src/main/java/com/flowingcode/addons/applayout/MenuItem.java

@@ -39,7 +39,7 @@
 @NpmPackage(value = "@polymer/paper-item", version = "3.0.1")
 @Tag("fc-menuitem")
 @JsModule("@flowingcode/fc-menuitem/fc-menuitem.js")
-@NpmPackage(value = "@flowingcode/fc-menuitem", version = "0.9.10")
+@NpmPackage(value = "@flowingcode/fc-menuitem", version = "0.9.11")
 public class MenuItem extends SlottedMenuItem
     implements HasOrderedComponents, HasMenuItemCommands<MenuItem>, HasMenuItemIcon<MenuItem> {
 
@@ -134,6 +134,15 @@ public MenuItem setHref(String href) {
     getElement().setProperty("href", href);
     return this;
   }
+  
+  public MenuItem setOpened(boolean opened) {
+    if (opened) {
+      getElement().setAttribute("opened", opened);
+    } else {
+      getElement().removeAttribute("opened");
+    }
+    return this;
+  }
 
   public MenuItem configure(Consumer<MenuItem> consumer) {
     consumer.accept(this);

src/test/java/com/flowingcode/addons/applayout/ApplayoutDemoView.java

@@ -262,10 +262,12 @@ private Component[] createMenuItems() {
           }),
       new MenuItem("SubMenu")
           .setIcon("build")
+          .setOpened(true)
           .add(
               new MenuItem("Hello Again", "inbox", () -> showContent("Hello Again!")),
               new MenuItem("And Again", () -> showContent("And Again!")),
               new MenuItem("SubMenu")
+              .setOpened(true)
                   .add(new MenuItem("Hello Again", () -> showContent("Hello Again!")))
                   .add(new MenuItem("And Again", () -> showContent("And Again!")))),
       new MenuSeparator("Separator"),