SettingsActivity $ SettingsFragment“$”的含义是什么？

Question

<com.google.samples.apps.iosched.ui.widget.DrawShadowFrameLayout
            android:id="@+id/main_content"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipChildren="false"
            app:shadowDrawable="@drawable/header_shadow">

            <fragment android:name="com.google.samples.apps.iosched.settings.SettingsActivity$SettingsFragment"
                      android:id="@+id/settings_fragment"
                      android:layout_width="match_parent"
                      android:layout_height="match_parent" />

        <LinearLayout style="@style/HeaderBar"
                      android:id="@+id/headerbar"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"
                      android:clickable="true"
                      android:orientation="vertical">

            <include layout="@layout/toolbar_actionbar" /> <!-- placeholder, empty except on L -->
        </LinearLayout>

        <!-- Butter bar -->
        <FrameLayout android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:layout_gravity="top"
                     android:layout_marginTop="?actionBarSize">
            <include layout="@layout/deprecated_include_butter_bar" />
        </FrameLayout>
    </com.google.samples.apps.iosched.ui.widget.DrawShadowFrameLayout>

    <!-- Nav drawer -->
    <include layout="@layout/navdrawer" />

</android.support.v4.widget.DrawerLayout>

com.google.samples.apps.iosched.settings.SettingsActivity $ SettingsFragment

$意味着??

settingsFragment是SettingsActivity中的静态内部类