Develop Reference

When centering vertically, how to account for action bar?

I'm centering properly, as you can see when you look at the content_main.xml design tab,
However, when you look activity_main.xml design with the action bar in place, while it is still centred in the app, it is not centred within the whitespace, which is what I would prefer. Any suggestions on how to account for the action bar? Preferably in the XML if possible.
Here is my XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/voting_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical"
android:layout_gravity="fill_vertical|center"
android:configChanges="orientation|screenSize"
android:screenOrientation="nosensor"
tools:context="com.gesslar.threshvote.MainActivity"
android:background="#color/colorFaded"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:showIn="#layout/activity_main">
<TextView android:id="#+id/textStatusMessage"
android:textColor="#color/colorText"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center" />
<ImageButton android:id="#+id/buttonVote"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:clickable="false"
android:src="#drawable/ic_vote_button_image"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:background="#android:color/transparent"
android:scaleType="fitCenter"
android:onClick="onVotePressed"
android:layout_gravity="center_horizontal|center_vertical"
android:adjustViewBounds="true"
android:contentDescription="#string/desc_vote_button" />
<TextSwitcher android:id="#+id/textCountdown"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:textColor="#color/colorText"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="#dimen/countdown"
android:includeFontPadding="false"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ProgressBar android:id="#+id/loadingBar"
style="#style/Widget.AppCompat.ProgressBar"
android:layout_gravity="end"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:visibility="invisible"
android:indeterminate="true"/>
</LinearLayout>

That xml worked for me:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/voting_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical|center"
android:background="#color/colorFaded"
android:configChanges="orientation|screenSize"
android:orientation="vertical"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:screenOrientation="nosensor"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.gesslar.threshvote.MainActivity"
tools:showIn="#layout/activity_main">
<TextView
android:id="#+id/textStatusMessage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#color/colorText" />
<ImageButton
android:id="#+id/buttonVote"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:adjustViewBounds="true"
android:background="#android:color/transparent"
android:clickable="false"
android:contentDescription="#string/desc_vote_button"
android:onClick="onVotePressed"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:scaleType="fitCenter"
android:src="#drawable/ic_vote_button_image" />
<TextSwitcher
android:id="#+id/textCountdown"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#id/buttonVote"
android:layout_gravity="center_horizontal"
android:gravity="center"
android:includeFontPadding="false"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#color/colorText"
android:textSize="#dimen/countdown" />
<ProgressBar
android:id="#+id/loadingBar"
style="#style/Widget.AppCompat.ProgressBar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="#id/textCountdown"
android:layout_gravity="end"
android:indeterminate="true"
android:visibility="invisible" />
</RelativeLayout>
But you need to run it on the device or emulator. Android Studio preview shows it wrong. The key line is app:layout_behavior="#string/appbar_scrolling_view_behavior"
EDIT
Also you need to use RelativeLayout - it supports good centering in parent. In LinearLayout you can center image only if your ImageView will be match_parent.

Android VideoView as background

I would to use a VideView as background in my layout.
So I would to have this videoView fullscreen and I need to add on this view other 'components' like TextView, EditView, ImageView...etc.
This is an example of my code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" tools:context=".Login"
android:alpha="0.9">
<VideoView
android:scrollbars="none"
android:clickable="false"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_gravity="center"
android:id="#+id/VideoView">
</VideoView>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:alpha="0.9">
<ImageView
android:id="#+id/imageView1"
android:layout_centerHorizontal="true"
android:layout_marginTop="15dip"
android:layout_width="130dp"
android:layout_height="100dp"
android:alpha="0.7"
android:src="#drawable/logoweb"/>
etc...
In this way I can't see the other components... only the video...

Try using FrameLayout.
FrameLayout always places things one on top of the other and always in reference to the upper lefthand corner,you can use something like this to acheive the above result
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
<VideoView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:id="#+id/VideoView"
/>
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center"
android:alpha="0.7"
android:src="#drawable/logoweb"
/>

TextView does not fit the screen

I have an activity with a TextView. I would like to align it on the bottom of the screen, in the center and I would like that the TextView fits the screen's width.
This is my XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:background="#ffffff"
tools:context=".ShowCard" >
<TextView
android:id="#+id/textView"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:background="#33000000"
android:textColor="#000000"
android:text="#string/lorem_ipsum" />
The result is not what I have expected to see. The TextView is not full-screen in the width, but leaves a small free space right and left (like padding/border, but I've not set padding/border!).
Do you know why? Suggestions?

try this
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/textView"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:background="#33000000"
android:textColor="#000000"
android:text="#string/lorem_ipsum" />
</RelativeLayout>

Excuse me, I'm a stupid guy!
I've not see that in the container XML code were included four padding rows:
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
I've deleted these rows and now everything is working correctly!
Sorry.

<TextView
android:id="#+id/textView"
android:layout_alignParentBottom="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:background="#33000000"
android:textColor="#000000"
android:text="#string/lorem_ipsum" />
Use the 'fill_parent' attribute, it should fill the entire width of the screen.

remove
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
from the parent relative layout.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffffff"
tools:context=".ShowCard" >
<TextView
android:id="#+id/textView"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:background="#33000000"
android:textColor="#000000"
android:text="#string/lorem_ipsum" />
use this

Why android button does align from top edge, but not from bottom edge?

I have a Button, I can align it by the distance from top.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/m1"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".OtherScreenActivity1" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="99dp"
android:background="#drawable/btn" />
</RelativeLayout>
But I want to align its position by the distance from bottom, not from top, and it does not work, it stays stick on bottom.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/m1"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".OtherScreenActivity1" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="99dp"
android:background="#drawable/btn" />
</RelativeLayout>

Not sure what the problem is but this what I have currently and the code seems to be working properly
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="10dp"
tools:context=".OtherScreenActivity1" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="99dp"
/>
Try this code and see if the xml is what you are looking for.

stick LinearLayour ( horizontal ) to the buttom without any space

Sorry, i've completed my question very much, so I reasked that and deleted prev post...
I'm using LinearLayout ( with 4 ImageButtons in a raw ) in a RelativeLayout in my project and I have used android:layout_alignParentBottom="true" for it ( linear ) to stick to the buttom of RelativeLayout, but my problem is the space between LinearLayout's ImageButtons and the corners of the screen. I want to remove them to make my ImageButtons be like a menu bar on the bottom of the screen. Is it possible for anyone to help me please ? THANK YOU ! :)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".HomeActivity">
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:gravity="center"
android:text="TXT"
android:textAppearance="?android:attr/textAppearanceLarge" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:orientation="horizontal"
android:weightSum="4" >
<ImageButton
android:id="#+id/calibrate"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#drawable/1" />
<ImageButton
android:id="#+id/chart"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#drawable/2" />
<ImageButton
android:id="#+id/guidance"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#drawable/3" />
<ImageButton
android:id="#+id/info"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#drawable4" />
</LinearLayout>
</RelativeLayout>
and the result is something like this : Picture http://uploadtak.com/images/c6645_1311.png!
1

Remove the padding on your RelativeLAyout
From:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".HomeActivity">
To:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >