Menus

From the google material design documentation

Menus allow users to take an action by selecting from a list of choices revealed upon opening a temporary, new sheet of material.

How to add?

I. In your build.gradle add latest appcompat library.

dependencies {  
    compile 'com.android.support:appcompat-v7:X.X.X'
    // where X.X.X version
}

II. Make your activity extend android.support.v7.app.AppCompatActivity.

public class MyActivity extends AppCompatActivity {  
   ...
}

III. Create a menu file inside the res/menu folder with some items on it.

<menu xmlns:android="http://schemas.android.com/apk/res/android"  
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      tools:context="com.example.saulmm.myapplication.MainActivity">

    <item
        android:id="@+id/action_refresh"
        android:title="@string/action_refresh"
        app:showAsAction="never"/>

    <item
        android:id="@+id/action_feedback"
        android:title="@string/action_feedback"
        app:showAsAction="never"/>

    <item
        android:id="@+id/action_settings"
        android:title="@string/action_settings"
        app:showAsAction="never"/>

    <item
        android:id="@+id/action_leave"
        android:title="@string/action_leave"
        app:showAsAction="never"/>
</menu>

IV. Override activity onCreateOptionsMenu method and inflate menu resource.

@Override
public boolean onCreateOptionsMenu(Menu menu) {  
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

How to style?

I. Declare a custom style extending the ThemeOverlay.AppCompat.Dark theme in your style.xml file.

<style name="MyPopupTheme" parent="ThemeOverlay.AppCompat.Dark">  
    <item name="android:colorControlActivated">@color/red </item>
    <item name="android:colorControlHighlight">@color/red</item>
    <item name="android:colorControlNormal">@color/yellow</item>
    <item name="android:textColorPrimary">@color/yellow</item>
</style>  

II. Apply this style to your Toolbar via app:popupTheme.

<android.support.v7.widget.Toolbar  
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    app:popupTheme="@style/MyPopupTheme" />