Develop Reference

What does FrameLayout do?

I'm new to programming. I was using Graphical Layout then when I was reading xml file, I saw FrameLayout. Then I searched, but I couldn't find something useful. What is FrameLayout and what does it do?

You use a FrameLayout to stack child views on top of each other, with the most recent child on top of the stack. In the example below, the TextView is the most recent, so it is automatically placed on top of the ImageView.
For example:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:id="#+id/backgroundImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
android:src="#drawable/bitmapie" />
<TextView
android:id="#+id/descTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginTop="70dp"
android:background="#android:color/holo_blue_light"
android:padding="10dp"
android:text="TextView placed at the top of the Imageview"
android:textColor="#android:color/white"
android:textSize="22sp" />
</FrameLayout>
Output:

FrameLayout is the simplest implementation of ViewGroup. Child views are drawn are in a stack, where the latest added view is drawn at the top. Usually you can use one of the next approaches or combine them:
Add a single view hierarchy into FrameLayout
Add multiple children and use android:layout_gravity to navigate them
Another popular approaches of using FrameLayout:
as a Fragment container
as an ancestor of your custom ViewGroup

You can consider the word frame as regular photo frame. What you do with that frame? you can place photos in that frame by one top to another. Same as in FrameLayout we can place views ( Any layout, or widget like button, text, image so on) top of other as #ojonugwa shows you the textview top of the Image.

Are you sure that you googled it?
http://www.tutorialspoint.com/android/android_frame_layout.htm
Frame Layout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other.
You can, however, add multiple children to a FrameLayout and control
their position within the FrameLayout by assigning gravity to each
child, using the android:layout_gravity attribute.
http://blog.neteril.org/blog/2013/10/10/framelayout-your-best-ui-friend/
The secret of FrameLayout is how it layouts its children. Although normally designed to contain one
item, it will happily stack up other element on top of each other.
Thus FrameLayout is essentially a way to manipulate the Z-order of
views on the screen.
This is super useful for a couple of UI tricks from HUD-like elements
to sliding panels to more complex animated transitions. In this post
we will see an example for each of those.
http://www.learn-android-easily.com/2013/05/frame-layout-in-androis.html
FrameLayout is designed to display a single item at a time. You can
have multiple elements within a FrameLayout but each element will be
positioned based on the top left of the screen. Elements that overlap
will be displayed overlapping. I have created a simple XML layout
using FrameLayout that shows how this works.

Basically it puts one view on top of another for example :
Inflating text on Image
<FrameLayout>
<ImageView>
<Textview>
</FrameLayout>

ActionBar overlay with GridView padding or custom GridView to show entire first image?

I have an activity with a GridView inside it. The ActionBar is set to overlay mode.
Right now, you can only see half of the first image because the ActionBar cuts it in half.
How do I add padding to the interior of the GridView so that it initializes in such a way that you can see the entire first image? Or is there another way? For example, how would I go about extending GridView to create one that has a built-in configurable, dynamic gap at the front?
example (although ListView instead of GridView): reddit is fun app: https://play.google.com/store/apps/details?id=com.andrewshu.android.reddit
edit: I'm hiding the ActionBar whenever the user scrolls down at a certain rate or past a certain level.

Use a ViewTreeObserver.OnGlobalLayoutListener in your Activity or Fragment to determine the number of columns your GridView will display (presuming it varies based on screen size and orientation), then use that number in your Adapter implementation. In getView(), if position is less than the number of columns, return an empty view whose height matches the Action Bar, otherwise bind your data as you would normally.
There is an excellent example that does exactly what you want in Google's "Displaying Bitmaps Efficiently" sample application: https://developer.android.com/training/displaying-bitmaps/display-bitmap.html
Here is the relevant source code:
https://android.googlesource.com/platform/development/+/master/samples/training/bitmapfun/src/com/example/android/bitmapfun/ui/ImageGridFragment.java

Try adding android:layout_marginTop="?android:attr/actionBarSize" to the parent of your GridView, or the GridView itself if it doesn't have one.
This will push your layout down so that it rests below the ActionBar.
Edit
You may want to conside using a ListView instead of a GridView. Reason being, you can easily achieve that effect by creating a fake header and then calling ListView.addHeaderView. You can't do the same with a GridView. What you're talking about can definitely be done with a GridView, but it will require you to subclass it and modify it quite a bit.
Header
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?android:attr/actionBarSize" />

Having ActionBar in overlay mode, the following works for me:
<GridView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?android:attr/actionBarSize"
android:clipToPadding="false"
android:numColumns="auto_fit"
android:columnWidth="120dp"
android:verticalSpacing="8dp"
android:horizontalSpacing="8dp"
android:stretchMode="columnWidth"
android:gravity="center"
android:id="#+id/gridLibrary" />
The most important lines here are: android:paddingTop and android:clipToPadding.
In my application, when I open an activity with the gridview above, the first row is fully visible. Then, when I scroll down, the ActionBar hides and the gridview fills up all the screen.

ListView populates from the bottom instead of from the top

I have a listView that expands upwards instead of downwards.
I have another listView on another page that works just fine and populates itself from the top -> bot.
Why does my listView start from the bottom instead of the top?
My XML
`
<ListView
android:id="#+id/list_view_showRegister"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/showRegister"
android:layout_alignParentLeft="true"
android:layout_marginTop="50dp"
android:clickable="false" >
</ListView>`

Your ListView is still actually populating from the top downwards. Just not from the top of the page.
You have set the layout_height="wrap_content" and the layout_above="#+id/showRegister". With the height being wrap_content, the view will only be as large as it's contents. Then, due to the fact you have used layout_above, it will be directly above another view.
The listview is not filling from the bottom, it is filling from the top (of the listview) - but the listview itself is only starting from halfway up the screen. Anything above the listview is not actually part of the listview, but empty space instead.
The solution is to either set the layout_height="match_parent", or remove the layout_above tag.
I know this is an old question but I hope this helps anyone else who may have found this issue via google.

Have a look a these links. Is it possible to make a ListView populate from the bottom?. populating from bottom.
Add new items to top of list view on Android?. Add new item at the top of list.

See for android:stackFromBottom attribute.

android How to add list view in a scrollview

I have a layout requirement like below,
Textview
TextView
ListView
Edit Text
Button
Since listview cannot fit in landscape, I want to have list view onwards (ie. listview, edittext and button) to be a scroll view.
I know listview cannot be used inside a scrollview, but is there a way to do that ?
Any working example will be appreciated.

99% of android developers think we should not use ListView inside a ScrollView because both are scrollbale views and only parent can be scrollable, so it wraps the ListView.
Its 100% correct. But we have to use tricks to avoid this and to achieve our requirements.
I found one trick in web, which is setting the height of ListView based on the list items. Just check the link below, you will get an example code to calculate the height of ListView to fit inside a ScollView.
Android ListView height calculation to fit in ScrollView
The problem with this code is the list view will be filled entire screen if more children are available.
You have to use below template to achieve solution to your requirement.
<ScrollView >
<LinearLayout vertical>
<TextView />
<TextView />
<ListView />
<EditText />
<Button />
</LinearLayout>
</ScrollView>
I saw one video on youtube, Android ListView inside a ScrollView which is showing we can limit the height of listview, can be scrollable and used inside a ScrollView. I don't know how the programmer achieved that.
I am also thinking to produce same result by avoiding above example code. I hope it may help you temporarily. Please let me know if you got solution.

The better solution for this kind of layout is that You should use relative layout and fix ur EditText and Button at the bottom of ur screen like i have in my list view(see the image below) so that you wont need to add ScrollView in ur layout.

Just do this
<ScrollView>
<LinearLayout>
<ListView>
</LinearLayout>
</ScrollView>
Then add your
EditText
Button

Sort of a round about way to do what you want to do without a scroll view.
Write a custom adapter for your ListView
Assume you have an array of n elements that you want to populate the ListView with and then the EditText and the Button. So number of elements will be n+2
In the getView for the position n+1 return a view which has an EditText box instead of the normal list item
For the n+2 position return a Button.
Don't try to wrap around a ListView with a ScrollView, you will need up with lot of issues.
Note: I have not tested this, not even sure if it will work. Do let me know if it works. :)

Scrollbar does not scroll while using dynamically filled listview

I am not able to scroll in a scrollview which contains a listview and is filled dynamically as I get data from the webservice.
I am able to do scrolling in emulator through mouse wheel, but in avtual device I can not scroll the list.
The attributes of scrollview are
<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10dp"
android:layout_weight="0.6"
android:fillViewport="true"
android:orientation="vertical"
android:padding="6.0dip"
android:scrollbarAlwaysDrawVerticalTrack="true"
android:scrollbarFadeDuration="5000"
android:scrollbarSize="20dp"
android:scrollbarStyle="insideOverlay"
android:scrollbars="vertical" >
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:orientation="vertical"
android:padding="2dp" >
<ListView
android:id="#+id/listbox_list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="599.84"
android:minHeight="250dp" >
</ListView>
</LinearLayout>
</ScrollView>
Please help me soon

by just looking at the layout_width and layout_height of your elements, it's clear that your scrollview will not scroll. unless you have a fixed height listview, never put a listview inside a scrollview (or in this case, a listview inside a layout that sits inside a scrollview).

I don't have any links to back this up right now, but it's not possible, and a well-known 'problem'. If you google a bit, or search here on SO, you'll find a number of topics covering this.
The problem arises in most cases when you have a scrolling view inside another scrolling view in the same direction. Consider the following example:
You have Two lists inside of a ScrollView.
Both lists are exactly one screen tall.
How do you scroll down to the second list?
When scrolling, how will your layout know if you are scrolling the list or the container?
This is basically the question that is the cause, and the only official solution is that it is as it should be, and there won't be a fix. Usually it is enough to have either a ListView or a ScrollView, but I have faced cases when you must have a listview in a scrollview (in my case a client wanted an iPhone-like datespinner in a scrolling page).
I solved it by using a FrameLayout, containing a custom ScrollView, and a ListView on top of that. Then in the code for the custom ScrollView, I added a line in the onScroll method that updated the top margin of the ListView, to psuh it upwards or downwards as the user scrolled. Surprisingly it worked.
NOTE: remember that:
The ListView handles its own scroll. If all you need is a scrolling
list, you do not need a ScrollView.
If you need a layout with a list and space for buttons or other
views, consider creating your layout so that the list only covers
enough space for you to fit your other views below/above without
scrolling.

Add following in your linear layout
android:scrollbars="vertical"
android:scrollbarAlwaysDrawVerticalTrack="true"