How to vertically fill space between elements in ScrollView while preserving scrolling - nativescript

Question

I am trying to achieve the following:
I tried achieving this with a GridLayout and only get one of the following two things working:
The space between the Label and the StackLayout is filled (label is
stretched), but scrolling will not work when adding more labels into
the StackLayout
Scrolling will work when more labels are added into
the StackLayout, but when only one label is showed for example, the
label before the StackLayout will not stretch
Is there any way to achieve such a thing? GridLayout is not necessarily needed, but I tried several ways and could not find any way of doing this.
example code of (1)
<Page class="page dark">
<ScrollView backgroundColor="red">
<GridLayout rows="*, auto" height="100%" backgroundColor="blue">
<Label backgroundColor="green">Top Label</Label>
<StackLayout row="1" backgroundColor="green">
<Label backgroundColor="purple">Label A</Label>
<Label backgroundColor="purple">Label B</Label>
</StackLayout>
</GridLayout>
</ScrollView>
</Page>
example code of (2):
<Page class="page dark">
<ScrollView backgroundColor="red">
<GridLayout rows="*, auto" backgroundColor="blue">
<Label backgroundColor="green">Top Label</Label>
<StackLayout row="1" backgroundColor="green">
<Label backgroundColor="purple">Label A</Label>
<Label backgroundColor="purple">Label B</Label>
</StackLayout>
</GridLayout>
</ScrollView>
</Page>

Answer 1

I wanted to achieve this for months and I finally found a working solution, for iOS and Android.
The solution is to use FlexboxLayout instead of GridLayout. When placed in a ScrollView, FlexboxLayout will take the whole available height if it is not tall enough. If it is taller than the ScrollView, it will be scrollable.
Here is the solution for your example:
<Page class="page dark">
<ScrollView backgroundColor="red">
<FlexboxLayout
flexDirection="column"
justifyContent="space-between"
alignItems="stretch"
backgroundColor="blue"
>
<Label backgroundColor="green">Top Label</Label>
<StackLayout backgroundColor="green">
<Label backgroundColor="purple">Label A</Label>
<Label backgroundColor="purple">Label B</Label>
</StackLayout>
</FlexboxLayout>
</ScrollView>
</Page>