How to add an item to a menu group in NavigationView

Question

In a word game for Android I currently have a hardcoded menu inflated from left_drawer_menu.xml and consisting of 3 groups (my turn, opponent turn and finally other

Answer 1

menu.add(R.id.my_move, i, i, "Item " + i);

You are also assigning the order (3rd param) as i. I am guessing that this is overriding the groupId. Try setting it as NONE as mentioned here

menu.add(R.id.my_move, i, NONE, "Item " + i);

Edit: Maybe something like this

MenuItem lastItem = menu.findItem(R.id.<lastItemId>);
int lastOrder= lastItem.getOrder();
menu.add(R.id.my_move, i, lastOrder-5, "Item " + i);

Order is a combination of category and order, so it might not be as straight forward as this.

Answer 2

On checking MenuItemImpl source code

     ...
     *    @param group Item ordering grouping control. The item will be added after
     *            all other items whose order is <= this number, and before any
     *            that are larger than it. This can also be used to define
     *            groups of items for batch state changes. Normally use 0.
     ...

    MenuItemImpl(MenuBuilder menu, int group, int id, int categoryOrder, int ordering,
        CharSequence title, int showAsAction) {

So you should define ordering in your xml (give same order to items in one group and increment in each following group)

<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <group android:id="@+id/my_move" android:checkableBehavior="single">
        <item
            android:orderInCategory="0"
            android:id="@+id/game1"
            android:icon="@drawable/ic_stars_black_24dp"
            android:title="Game #1" />
        <item
            android:orderInCategory="0"
            android:id="@+id/game2"
            android:icon="@drawable/ic_stars_black_24dp"
            android:title="Game #2" />
    </group>
    <group android:id="@+id/his_move" android:checkableBehavior="single">
        <item
            android:orderInCategory="1"
            android:id="@+id/game5"
            android:icon="@drawable/ic_clock_black_24dp"
            android:title="Game #5" />
        <item
            android:orderInCategory="1"
            android:id="@+id/game6"
            android:icon="@drawable/ic_clock_black_24dp"
            android:title="Game #6" />
        <item
            android:orderInCategory="1"
            android:id="@+id/game7"
            android:icon="@drawable/ic_clock_black_24dp"
            android:title="Game #7" />
    </group>
    .....

</menu>

and give an appropriate order value while adding the item in your code. So if you want to add the item at the end of first group, add it as:

menu.add(R.id.my_move, Menu.NONE, 0, "Item1");

and if you want to add to second group, add it as:

menu.add(R.id.his_move, Menu.NONE, 1, "Item2");

The problem with your code could be that all items in the xml have default orderInCategory 0 and so the new item gets added after all these items.

UPDATE

To add icon use setIcon method for MenuItem

menu.add(R.id.my_move, Menu.NONE, 0, "Item1").setIcon(R.drawable.ic_stars_black_24dp);

Answer 3

I've solved it this way:

1. Set up the menu:

   <?xml version="1.0" encoding="utf-8"?>
   <menu xmlns:android="http://schemas.android.com/apk/res/android">
       <item android:title="my moves"
             android:id="@+id/submenu_1">
           <menu>
               <item
                   android:id="@+id/my_dummy_item_1"
                   android:icon="@drawable/ic_menu_camera"
                   android:title="Import" />
               <item
                   android:id="@+id/my_dummy_item_2"
                   android:icon="@drawable/ic_menu_gallery"
                   android:title="Gallery" />
               <item
                   android:id="@+id/add_item"
                   android:icon="@drawable/ic_menu_manage"
                   android:title="Add Item" />
           </menu>
       </item>
       <item android:title="opponent's moves"
             android:id="@+id/submenu_2">
           <menu>
               <item
                   android:id="@+id/opponent_dummy_item_1"
                   android:icon="@drawable/ic_menu_camera"
                   android:title="Import" />
               <item
                   android:id="@+id/opponent_dummy_item_2"
                   android:icon="@drawable/ic_menu_gallery"
                   android:title="Gallery" />
               <item
                   android:id="@+id/opponent_dummy_item_3"
                   android:icon="@drawable/ic_menu_manage"
                   android:title="Tools" />
           </menu>
       </item>
   </menu>
   

2. In onNavigationItemSelected(), get MenuItem you want to expand by order id (or via findItem()), then get SubMenu from it and add new item into it:

   @SuppressWarnings("StatementWithEmptyBody")
   @Override
   public boolean onNavigationItemSelected(MenuItem item) {
       int id = item.getItemId();
   
       if (id == R.id.add_item) {
           Random r = new Random();
           int i = r.nextInt(100);
           MenuItem myMoveGroupItem = navigationView.getMenu().getItem(0);
           // MenuItem myMoveGroupItem = navigationView.getMenu().findItem(R.id.submenu_1);  -- it also works!
           SubMenu subMenu = myMoveGroupItem.getSubMenu();
           subMenu.add("Item "+i);
       }
   
       return true;
   }
   

I hope, it helps