TextView expands layout but webview does not - android-layout

Question

I've got a layout with a textview with some buttons at the bottom. The textview is set to expand to fill the space. This is fine. However, when I change the textview to a webview, the webview does not expand to fill the space. What's wrong?
This is working fine:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ScrollView
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
>
<!-- height set to fill because background is black and we want
the light background -->
<TextView
style="#style/subtopicView"
android:id="#+id/subtopic_content"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</ScrollView>
<include layout="#layout/include_html_view_footer" />
</LinearLayout>
This is not, but the only change is the textview to a webview and all other values remain the same.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ScrollView
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
>
<!-- height set to fill because background is black and we want
the light background -->
<WebView
style="#style/subtopicView"
android:id="#+id/subtopic_content"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</ScrollView>
<include layout="#layout/include_html_view_footer" />
</LinearLayout>
the include is simply this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#color/tintedColour"
android:orientation="horizontal"
android:paddingBottom="#dimen/spacer"
android:paddingTop="#dimen/spacer" >
<Button
android:id="#+id/PrevPage"
style="?android:attr/buttonStyleSmall"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#string/previous" />
<Button
android:id="#+id/NextPage"
style="?android:attr/buttonStyleSmall"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#string/next" />
<Button
android:id="#+id/Copy"
style="?android:attr/buttonStyleSmall"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#string/copyclipboard" />
</LinearLayout>
Thanks for any help.

Answer 1

It's generally a bad idea to nest scrollable elements like you have done by including a WebView inside a ScrollView. Touch events will be unpredictable, and it would probably be a better idea to drop the ScrollView altogether.
That said, the height of your WebView is set to fill_parent. However, the ScrollView is simultaneously trying to minimize the size of its children. As Romain Guy writes in a blog post on this topic:
In attempt to achieve this effect, I have seen several Android developers try to set the height of the view inside the scroll view to fill_parent. Doing so does not work and leads to the following result:
To understand this result, you must remember that android:layout_height=”fill_parent” means “set the height to the height of the parent.” This is obviously not what you want when using a ScrollView. After all, the ScrollView would become useless if its content was always as tall as itself.
By setting android:fillViewport="true", the scroll view’s child expands to the height of the ScrollView. (When the child is taller than the ScrollView, the attribute has no effect.)