<ScrollView android:layout_width="fill_parent" android:id="@+id/scrollView1"
        android:layout_height="fill_parent">
        <LinearLayout android:id="@+id/linearLayout1"
            android:layout_width="fill_parent" android:orientation="vertical"
            android:layout_height="fill_parent">
            <ListView android:id="@+id/listView1" android:layout_width="fill_parent"
                android:layout_height="fill_parent"></ListView>
        </LinearLayout>
    </ScrollView>

scrollview填充整个屏幕,但linearLayout1仅填充屏幕的一小部分高度近100dip的部分.如何使linearLayout1填充父项？