Develop Reference

What does child mean in an android layout?

I am new to Android Development, so what is meant by child in the below paragraph....
A ScrollView is a FrameLayout, meaning you should place one child in
it containing the entire contents to scroll; this child may itself be
a layout manager with a complex hierarchy of objects. A child that is
often used is a LinearLayout in a vertical orientation, presenting a
vertical array of top-level items that the user can scroll through.
https://developer.android.com/reference/android/widget/ScrollView.html

In android (and most other technologies), views can have subviews, aka "children". Most views can have children and can be a child of a parent view. It's kind of like a "tree".
The most obvious feature of being a child of some other view is that the child moves with the parent view. Another feature is that the child is in the coordinate space of the parent view.
Your paragraph here basically says you can only put one child view in ScrollView and it is usually a LinearLayout. But don't be fooled! This child can have its own child views.

Gaurav i think this is what you looking for, you need to use only one LinearLayout tag inside ScrollView tag, if you are using more than one LinearLayout than it will show error. If you want to use more LinearLayout tag you can use them inside LinearLayout tag which is inside ScrollView tag. May be this will help you.

You need to understand the general concept of child and parent . Simply you can think of the real life relation between parent and child.on the hierarchy parents are toplevel and child is below.so when you come to android layout parent is container and child is the content.

How to prevent the child from affecting parent in expandablelistview android?

Here I have expandablelistview in activity and as child I have dynamic TableView which is added into FrameLayout.
When I scroll TableView vertically then it affect its parent scrollview that means whole ExpandableListview scrolled. Now I want that when I scroll TableView Content at that time I don't want to scroll ExpandableListView.
I have also tried v.getParent().requestDisallowInterceptTouchEvent(true); and googling for that but i didn't get any solutions.
Help me guys.

Is it possible to have a ScrollView inside another ScrollView?

I want to learn how to solve this problem. I want to have a Horizontal scrollview with the scroll blocked (the user should not be able to scroll it) and inside that horizontal scrollview i want to have another horizontal scroll view, and this scrollview must be able to be scrolled by the user (it haves more content that the width of the screen).
Is it possible to do it?
I tried using this on the parent horizontal scroll view:
((HorizontalScrollView) view).setHorizontalScrollBarEnabled(false);
((HorizontalScrollView) view).setEnabled(false);
((HorizontalScrollView) view).setFocusable(false);
((HorizontalScrollView) view).setFocusableInTouchMode(false);
and this on the child horizontal scroll view:
((HorizontalScrollView) view).requestFocus();
It is not working, the child appears to have a scroll bar, but it cannot be scrolled.
How can this be solved?
PD: I know that this is not a good practice, but I want to learn how to achieve this goal.

You should never use a
HorizontalScrollView with a ListView,
since ListView takes care of its own
scrolling. Most importantly, doing
this defeats all of the important
optimizations in ListView for dealing
with large lists, since it effectively
forces the ListView to display its
entire list of items to fill up the
infinite container supplied by
HorizontalScrollView.
http://developer.android.com/reference/android/widget/HorizontalScrollView.html
UPDATE:
Since you may be forced to use a two dimensional scrollview, you may consider using this:
http://blog.gorges.us/2010/06/android-two-dimensional-scrollview/
I haven't used this but it may be a reasonable approach.

you can do it. But you have to handle child layouts in scrollview i.e ScrollView can host only one direct child.

How to getting the page number or correct posi in an Android ScrollView

I have a LinearLayout containing two ImageViews. The LinearLayout is inside the ScrollView.
When I scroll the screen I would like to know the exact position of the two ImageViews relative to scroll. The getScrollY() doesn't work correctly because the ImageViews continues scrolling after action_up and the value in getScrollY isn't updated in this case. I have this information to disable or enable other elements on screen.

If your 2 views are the same/similar then add them to a ListView, then you can set an OnScrollListener which will tell you when the view is scrolled and the index of the visible item.

ExpandableListView affecting the size of Scrollview when collapsing and expanding

Let me try to explain what I want to achieve. Currently, I have a ScrollView as the main view for my layout and a linearLayout within that to place all of my content into.
In my LinearLayout, I have a bunch of textviews and a gallery, which extends out of the screen, so the user can scroll to see everything. It works.
Now, I want to add an expandableListView to the bottom of all that content, which is still in the linearLayout. The problem is when you expand the list view groups it doesn't affect the ScrollView. I had envisaged that when you expand a group it would make the linearLayout bigger, which in turn makes the scrollview bigger.
Is what I'm thinking achievable?
EDIT:
Ok I think the situation is that listViews are normally placed in a layout by themselves and have scrollviews already enabled. You just set it to fill_parent and it works fine. However, in my case, I'll need the expandableListView to display all content without scrolling, because my ScrollView will deal with that. I don't even think it possible?

It's difficult to answert without seeing your layout xml, but I think that if you set the android:layout_height of the linear layout and expandableListView to wrap_content, the first scrollView must scroll the whole view.

have you tried putting your expandable list into another linear layout and than put it in the scroll views default linear layout?