设置ScrollView的属性android:fillViewport=”true” 即可
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="20dp"
android:background="@color/red"
android:orientation="vertical">
</LinearLayout>
</FrameLayout>
</ScrollView>