Is it possible to grey out (not just disable) a MenuItem in Android?

I had the same issue. There are two ways of getting this to work:

1. Put your icons in a StateList so that a different icon will be used on disable

2. What I use now. Change the icon yourself with something like this in onPrepareOptionsMenu():

   public boolean onPrepareOptionsMenu(Menu menu) {
       boolean menusEnabled = reachedEndOfSlidehow(); // enable or disable?
       MenuItem item = menu.findItem(R.id.menu_next_slide);
       Drawable resIcon = getResources().getDrawable(R.drawable.ic_next_slide);
   
       if (!menusEnabled)
           resIcon.mutate().setColorFilter(Color.GRAY, PorterDuff.Mode.SRC_IN);
   
       item.setEnabled(menusEnabled); // any text will be automatically disabled
       item.setIcon(resIcon);
   }
   

You can call invalidateOptionsMenu() (or from ABS, supportInvalidateOptionsMenu()) to rebuild the menu.

EDIT: Updated solution 2

Source: https://groups.google.com/forum/?fromgroups#!topic/actionbarsherlock/Z8Ic8djq-3o

On all android versions, easiest way to use this to SHOW a menu action icon as disabled AND make it FUNCTION as disabled as well:

@Override
public boolean onPrepareOptionsMenu(Menu menu) {

    MenuItem item = menu.findItem(R.id.menu_my_item);

    if (myItemShouldBeEnabled) {
        item.setEnabled(true);
        item.getIcon().setAlpha(255);
    } else {
        // disabled
        item.setEnabled(false);
        item.getIcon().setAlpha(130);
    }
}

I found a new way to solve this issue using a drawable selector xml file. You just create a selector with the icon you want to use in your menu item, then you can either change the tint, alpha or both of the bitmap:

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

    <item android:state_enabled="true">
        <bitmap android:src="@drawable/ic_menu_item"
            android:tint="@color/enabled_color"
            android:alpha="@integer/enabled_alpha"/>
    </item>

    <item android:state_enabled="false">
        <bitmap android:src="@drawable/ic_menu_item"
            android:tint="@color/disabled_color"
            android:alpha="@integer/disabled_alpha"/>
    </item>
</selector>

As a side note; I like to set the tint to "?android:attr/textColorPrimary" for enabled state and "?android:attr/textColorHint" for disabled state. This way it will adjust depending on the theme used.

---

Then you can just set the icon in your menu xml file to the selector resource:

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

    <item android:id="@+id/menu_action"
        android:orderInCategory="0"
        android:title="@string/title_menu_action"
        android:icon="@drawable/ic_menu_item_selector"
        app:showAsAction="ifRoom"/>

</menu>

Then when you call item.setEnabled(enabled) the color and/or alpha of the icon will change along with the state!