Develop Reference

How to indicate position to the center of the parent in java code?

I am confused on the following:
If I have a LinearLayout as part of a hierarchy and I want to programmatically change its position so that it is in the center of the parent layout how can I do this?
There are too many gravity attributes.
Should I update the gravity of the layout params of the item or of the parent?

If the parent is a LinearLayout you can use android:layout_gravity="center" on that view to center it in its parents view.
If the parent is a RelativeLayout you can use
android:layout_centerInParent="true"
I would generally use a RelativeLayout as a parent view if you want to center views inside it

ListView with relative layout and scrollview

I am using a scrollview in which i have added 3 relative layout and a list so the stack is like
Scrollview
Relative Layout
Relative Layout
______ ListView
Relative Layout
Now when i am trying to add entries in listview it is now increasing its height. I have set wrap_content for the height field.

Use only listView and add the relativeLayouts as headers/footers.

Fix the height of listview because you are using scrollview
you can scroll and view that list while scrolling content inside listview.

Scroll a View and refresh content

I use the following user interface:
A parent relative layout parentLayout with the dimensions 800x600 (width x height)
A second relative layout childLayout, which is a child of the parent layout.
It has the dimensions 800x1000, i.e. it is larger than the parent layout.
parentLayout.addView(childLayout);
My goal: Scrolling childLayout by using childLayout.scrollTo(x,y).
When I use childLayout.scrollTo(x,y), Android scrolls childLayout but doesn't refresh (redraw) it. The effect is, that childLayout is cut to the same dimensions as parentLayout.
Unfortunately, the following solutions don't solve the problem:
childLayout.scrollTo(x,y);
childLayout.invalidate();
childLayout.requestLayout();
Any ideas how to solve this problem?

You can use parentLayout as ScrollView instead of RelativeLayout and keep childLayout as RelativeLayout.

How to add more Items in Scrollview in Android?

My android page has 10 EditText and 10 TextView. but there is no space in my screen in the Graphical Layout. i just added 5 only. im using Scroll layout. how to add additional 5 items in the screen without reducing the items height. Is there any coding here.?

<ScrollView>
<LinearLayout>
<TextView/>..
....
..
</LinearLayout>
</ScrollView>
You can add multiple items inside a LinearLayout. Since ScrollView is scrollable it won't affect the dimensions of the Views inside. You can add as many views as you need without worrying about screen size or View size..

You should add a LinearLayout as the only child inside your ScrollView. Then get a reference to that LinearLayout :
mLayout=(LinearLayout)findViewById(R.id.myLayout);
and then add Views dynamically from code using :
EditText et=new EditText(...);
//....
mLayout.addView(et);

A ScrollView can have only one direct child, so you need to put all the other Views in a Layout, such as LinearLayout and put that layout in ScrollView
Make your ScrollView's height as match_parent and the inner LinearLayout's height as wrap_content. The LinearLayout will stretch according to the number of children inside it and if the height exceeds the height of the ScrollView, the overflow can be seen by scrolling. If the ScrollView and inner Layout both have same height or if ScrollView have larger height than inner Layout, the scrolling won't happen for obvious reason.

Centering a scroll view

I'm trying to have a ScrollView centered top to bottom within its parent, but I'd also like the ScrollView to be no taller than the height of it's child. The child's height is variable. If there is room, the ScrollView should stretch to be exactly the height of it's child. Any suggestion on how to set up this layout?

Put the ScrollView inside a android:layout_height="match_parent" RelativeLayout.
set the ScrollView to android:layout_centerVertical="true".
Set the ScrollView's height to android:layout_height="wrap_content".
This should get you a centered scrollview that is up to but no taller than the relativelayout that contains it.
Out of curiosity, why do you not want the scrollview set to fill_parent/fillViewport? I would suggest doing that, and simply centering the content of the scrollview instead.