Horizontalscrollview does not wrap_content below a certain height

Question

As you can see from the xml imagebutton,linearlayout and Horizontalscrollview have wrap_content for their height.But it seems that the Horizontalscrollview sometimes has more height than linearlayout.Its height is supposed to be equal to that of its child.

How can I make the height of Horizontalscrollview equal to its child using wrap_content?

<?xml version="1.0" encoding="utf-8"?>
   <HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/scroll_buttons"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/bottom_bar_light"
    android:fillViewport="true" >

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <ImageButton
            android:id="@+id/new_file"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/new_item" />

        <ImageButton
            android:id="@+id/multi_select"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/discard_small" />

        <ImageButton
            android:id="@+id/refresh"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/refresh_small" />

        <ImageButton
            android:id="@+id/home_grid"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/grid_small" />

        <ImageButton
            android:id="@+id/info_button"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/info_small" />

        <ImageButton
            android:id="@+id/exit"
            android:layout_width="75dp"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:src="@drawable/exit" />
    </LinearLayout>

</HorizontalScrollView>

Answer 1

Make sure the background drawable that you use for the HorizontalScrollView, @drawable/bottom_bar_light, is not too big to force the widget be taller than it should.