layout_weight does not work when the layout inside a ScrollView is larger than the ScrollView

Question

I'm trying to use a linear layout's layout_weight for the height inside of a scrollview. However I find that layout_weight would only work with fillViewPort=true and if there is enough remaining space for the linear_weight to expand.

I have listed three examples below and I want to make textView the same size in #2 and #3 as #1 in xml level. As you can see in the link, in #2, #3, textView was automatically changed.

Here are my examples. The TextViews and Buttons are enclosed inside of a LinearLayout and then inside of a scrollView.

1. Layout_weight working perfectly relative to the parent. (Working)

2. Layout_weight working relative to the remaining space and not the parent.(Not Working)

3 Layout_weight ignored (Not Working)

Here's my xml code for #3. #2 and #1 is basically the same code with less or no buttons.

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/scroller"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:weighSum="1"
    android:fillViewport="true" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:weightSum="10" >

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />

        <Button
            android:layout_width="30dip"
            android:layout_height="30dip"
            android:text="Accept" />


        <TextView
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="6"
            android:background="#AAABBB"
            android:text="hello" />

        <TextView
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="3"
            android:background="#BBBAAA"

            android:text="hello" />

        <TextView
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="5"
            android:background="#AAABBB"

            android:text="hello" />
    </LinearLayout>

</ScrollView>

Answer 1

The weights are working as they were designed. Maybe not the way you want them to "work", but saying they are "not working" is inaccurate. Think about your 3rd case for a second, what size in pixels would you expect the TextViews to be? Weights are a percentage of the available space (not total size of the parent). The scrollview and linearlayout are, at a minimum, the size of your screen, otherwise the sum of all the children views. So if your children views exceed the size of the screen (the ones without weights), how much space do you expect to be allocated for the remaining views (the ones with 0dp and weights)? The point is that amount of space is arbitrary, android will not try to assume how much space you want, because it has no possible way of knowing.

TL;DR - set a minHeight (in dp) on your textviews to handle the case where you have too many buttons.