我正在制作一个布局，其中我使用 Scrollview 将内容放入视图中。但是在视图中，我将滚动条向下移动，然后移动到下一个视图，滚动条保持在相同的位置，即在视图的底部。我想确保滚动条始终保持在视图的顶部，默认情况下。这是 XML：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerHorizontal="true"
android:orientation="vertical" >
<ScrollView
android:id="@+id/scrollView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="90.0dip"
android:layout_marginLeft="1.0dip"
android:layout_marginRight="1.0dip"
android:layout_marginTop="1.0dip"
android:fadeScrollbars="true"
android:fadingEdge="none"
android:fillViewport="true" >
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:visibility="visible" >
<ImageView
android:id="@+id/explain_QuestionImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="visible" />
<TextView
android:id="@+id/explain_question"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@id/explain_QuestionImageView"
android:fadingEdge="vertical"
android:scrollbars="vertical"
android:text=""
android:textColor="@color/question_text"
android:textColorHighlight="@color/question_text1" />
<TextView
android:id="@+id/explain_separator"
android:layout_width="match_parent"
android:layout_height="5.0dip"
android:layout_alignParentRight="true"
android:layout_below="@id/explain_question"
android:background="@drawable/blue_gradient"
android:fadingEdge="vertical"
android:padding="10dp"
android:scrollbars="vertical"
android:text="" />
<TextView
android:id="@+id/explain_explaination"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@id/explain_separator"
android:fadingEdge="vertical"
android:padding="10dp"
android:scrollbars="vertical"
android:text=""
android:textColor="@color/dark_green" />
</LinearLayout>
</FrameLayout>
</ScrollView>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
>
<com.google.ads.AdView
android:id="@+id/ad"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:keepScreenOn="true"
ads:adSize="BANNER"
ads:adUnitId="a1501e5633125fb"
ads:loadAdOnCreate="true"
ads:testDevices="TEST_EMULATOR, 123456789ABCDEF" >
</com.google.ads.AdView>
<LinearLayout
android:id="@+id/LL_Buttons1"
android:layout_width="fill_parent"
android:layout_height="40.0dip"
android:layout_above="@id/ad"
android:layout_gravity="bottom"
android:background="#ff777777"
android:orientation="horizontal" >
<Button
android:id="@+id/PrevExplainationButton"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerInParent="true"
android:layout_marginLeft="2.0dip"
android:layout_weight="1.0"
android:background="@drawable/ibtn"
android:onClick="onPrevExplainationButtonClick"
android:text="Previous" />
<Button
android:id="@+id/NextExplainationButton"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_centerInParent="true"
android:layout_marginLeft="5.0dip"
android:layout_marginRight="2.0dp"
android:layout_weight="1.0"
android:background="@drawable/ibtn"
android:onClick="onNextExplainationButtonClick"
android:text="Next" />
</LinearLayout>
</RelativeLayout>
</RelativeLayout>
请告诉我该怎么做。