Develop Reference

Cast shadow on top of LinearLayout using android:elevation

I have this LinearLayout that is going to be placed on the bottom of an activity layout. I want this LinearLayout to have a 4dp elevation, just like the top toolbar should have, however, since android:elevation places the shadow below the ui component and this specific component (linearLayout) is going to be on the bottom of the screen, I won't see any elevation at all..
This is my LinearLayout code, and an image of it with the default elevation implemented:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="3"
android:background="#android:color/transparent"
android:orientation="horizontal"
android:elevation="4dp"
android:layout_alignParentBottom="true">
<ImageButton
android:id="#+id/playButton"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:scaleType="center"
android:clickable="true"
android:background="#drawable/bottom_toolbar_menu_selector"
android:src="#drawable/ic_play"
style="?android:attr/borderlessButtonStyle" />
<ImageButton
android:id="#+id/stopButton"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:scaleType="center"
android:clickable="true"
android:background="#drawable/bottom_toolbar_menu_selector"
android:src="#drawable/ic_stop"
style="?android:attr/borderlessButtonStyle" />
<ImageButton
android:id="#+id/bookmarkButton"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:scaleType="center"
android:clickable="true"
android:background="#drawable/bottom_toolbar_menu_selector"
android:src="#drawable/ic_bookmark"
style="?android:attr/borderlessButtonStyle" />
</LinearLayout>
Is there a way, using elevation to place a shadow on top of the ui component?
Thanks in advance!

You can't theoretically do it with android:elevation, in the sense that you can't choose the direction where the shadow is going to be cast.
There are two solutions.
1. Drawables
You could, for instance, put an ImageView right above your layout and set android:src="#drawable/shadow". This should be a vertical GradientDrawable defined in XML, as explained here.
2. Workaround
While most of the shadow is actually below the view, a subtle shadow is also above. A workaround might be using a very high value for elevation, like 40dp: the bottom part is going to be hidden due to your layout, while the top is going to be expanded and look like a common shadow.
In either case, you do not have control over the elevation value in dp, in the sense that you can't be sure your shadow is equivalent to the one cast by android:elevation=4dp.

use like as;
<LinearLayout
android:layout_width="match_parent"
android:layout_height="205dp"
android:background="#color/white"
android:orientation="horizontal">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_marginTop="-5dp"
android:background="#color/white"
android:elevation="3dp"
android:paddingTop="5dp">
// CHILD VIEWS
</RelativeLayout>
</LinearLayout>

Add this code above of view in which you want top elevation or add android:layout_marginTop="-4dp" and add below of above view
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="0.01dp"
android:layout_below="#+id/scrollbar"
app:cardBackgroundColor="#android:color/transparent"
app:cardCornerRadius="0dp"
app:cardElevation="#dimen/dp_4" />

Try this i am unable to set background through xml then i tried the programmatic way to solve that and i work perfectly refer this if facing problem on show shadow in Linear Layout
lprofile.setBackgroundResource(R.drawable.background_with_shadow);
lprofile is my ref of Linear layout and background_with_shadow is xml for applying shadow i hope i will for ur requirmement...thank u..

Android/XML - How to align an immobile layout to top of parent and have scrollview below?

Please refer to example below. I want to have the top layout (below encased in red) to be unmoving in a scrollview in my activity. I have a scrollview as the parent layout and then I thought having a relative layout for the top one would work, and align it to the top, but that didn't really work out as it still remained within the scrollview. I would like to have the users have the red-layout box remain static when they scroll down.
I figure I would also have to put in a topMargin at the top of the scrollview or something in order to fit the redbox layout in.
XML Code posted here: http://pastebin.com/bxdREbeG

Do something like this (hand code, for reference only):
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="#+id/YourTopStaticView"
android:layout_width="match_parent"
android:layout_height="48dp"> //Or any other height you want
//Contents of the top view
</RelativeLyout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/YourTopStaticView">
//Contents of the ScrollView
</ScrollView>
</RelativeLayout>
As a side note, do not hardcode children into the ScrollView like that. Use the RecyclerView (which is an updated, modern replacement for ListView), which you will be expected to know how to use if you want to move into serious Android programming. It is actually super easy to use, once you get the hang of it :-)

You should use the ScrollView with only one child (official documentation - http://developer.android.com/reference/android/widget/ScrollView.html). According to your xml, your ScrollView is very complicated with a lot of child widgets.
The best option for you is to use a LinearLayout as the root for the whole container, a LinearLayout( or Relative) for the top layout containing the Reset and Save buttons, and a ListView for the long list that you have. ListView takes care of it's own scrolling. So you don't have to worry about that.
This will improve your code performance as well.

This should suit your needs:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout android:id="#+id/topPanel"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp">
<TextView android:id="#+id/label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:text="Multi TTS Implementation"/>
<Button android:id="#+id/save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:text="SAVE"/>
<Button android:id="#+id/resetAll"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLeftOf="#id/save"
android:layout_centerVertical="true"
android:text="RESET ALL"/>
</RelativeLayout>
<ScrollView android:id="#id/scroll"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_below="#id/topPanel"
android:layout_alignParentBottom="true"
android:padding="5dp">
<!-- Your scrollable content here -->
</ScrollView>
</RelativeLayout>

Center ListView horizontally

As easy as it seems to be, as stubbornly this ListView won't center itself (or it's content within - doesn't matter to me).
This is activity layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context="com.drobiazko.den.mobineon.MainActivity"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center_horizontal"
android:background="#drawable/bg">
<RelativeLayout android:id="#+id/clock_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<!--<RelativeLayout android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/holo_blue_dark">-->
<com.drobiazko.den.mobineon.ListViewRowsHeight
android:id="#+id/listview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:overScrollMode="never"
android:scrollbars="none"
android:divider="#null"
android:listSelector="#android:color/transparent"
android:persistentDrawingCache="scrolling|animation"
android:background="#android:color/holo_green_dark" />
<!--</RelativeLayout>-->
</LinearLayout>
This is ListView's item layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView android:id="#+id/btn_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_icon" />
<TextView android:id="#+id/btn_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_name" />
<TextView android:id="#+id/btn_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_btn_count" />
</RelativeLayout>
I've tried everything (including simplifying layout to max), but it still won't go.
Funny that the first relative layout clock_container - centers like a charm, due to parent LinearLayout's android:gravity="center_horizontal". Why won't ListView?
Added later:
Inspired by FOliveira's answer, I've done some investigation and found that:
everything works fine, parent LinearLayout has android:gravity="center_horizontal" and centers his children respectfully. The reason for ListView's children are left-aligned is that ListView takes all possible width despite his android:layout_width="wrap_content" attribute.
Anyone knows why is that?

First of all , i would remove the first linear layout and stay only with the relative layout as the parent.
After having the relative layout as the main parent , set the CENTER_IN_PARENT attribute to true.
The mistake you are making is that you are setting the gravity of Linear Layout child to center horizontal, which is correct, but the only children being affected by this option is the Relative layout itself.

RelativeLayout positioning issue with first child LinearLayout using margin

I'm currently trying to position some LinearLayouts (which are then filled with some images) on an absolute position on the screen. Currently the LinearLayouts are alinged to the top-left of the parent RelativeLayout and then positioned using margins. This works properly for all child LinearLayouts EXCEPT the first one in the list. Setting some margins (as for example 25dp for the left margin) does not show any effect in this case. I hope someone has had the same issue and can provide some guidance.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/rl_page"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout android:id="#+id/ll_first" android:layout_height="wrap_content" android:layout_width="wrap_content"
android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginLeft="25dp" android:layout_marginTop="20dp"></LinearLayout>
<LinearLayout android:id="#+id/ll_second" android:layout_height="wrap_content" android:layout_width="wrap_content"
android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginLeft="175dp" android:layout_marginTop="30dp"></LinearLayout>
<LinearLayout android:id="#+id/ll_third" android:layout_height="wrap_content" android:layout_width="wrap_content"
android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginLeft="40dp" android:layout_marginTop="140dp"></LinearLayout>
</RelativeLayout>
Edit:
Example image http://i.stack.imgur.com/HuYjU.jpg

The RelativeLayout provides some tags for the positioning of Views/ViewGroups relative to another View/ViewGroup.
android:layout_below="id" and android:layout_above="id"
This will put the View below/above another View with the id.
android:layout_alignRightOf="id" and android:layout_alignLeftOf="id"
This will put the View to the right/left of another View with the id.
All tags have the same usability like this, where I use the android:layout_below="" to set a View/ViewGroup below another:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/rl_page"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<--! YOUR LAYOUT AT THE TOP OF YOUR PARENT -->
<LinearLayout
android:id="#+id/ll_first"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"></LinearLayout>
<LinearLayout android:id="#+id/ll_second"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_below="#id/ll_first" ></LinearLayout>
<LinearLayout
android:id="#+id/ll_third"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_below="#id/ll_second"></LinearLayout>
</RelativeLayout>
Now you can use some margins for the position of every View.

How to put one View over other in RelativLlayout programmatically in Android?

I am programmatically creating view in Android. Parent layout is RelativLlayout and I'm adding two views in it. First is ListView and second is custom view. I want my second custom view to come on top of the list, but somehow it is getting hidden behind the ListView. How do I make sure that my custom view is on top.

Views get placed in the order you add them to their parent views. The view added last will be on top. You might also want to try
View.bringToFront() http://developer.android.com/reference/android/view/View.html#bringToFront()

Try to use: View.bringToFront();

Solution 1 - View#bringToFront()
View.bringToFront() should work if used properly. Maybe you forgot this (source: http://developer.android.com/reference/android/view/View.html#bringToFront()):
Prior to KITKAT this method should be followed by calls to requestLayout() and invalidate()
Solution 2 - reattach view
If View.bringToFront() will not work try to remove and add the view again. The advantage is that it has the same code on pre-KITKAT versions too.
I am doing it this way in my code:
ViewGroup parentView = (ViewGroup) (listView.getParent());
parentView.removeView(addFab);
parentView.addView(addFab);

Use FrameLayout, frame layout shows last added view on top..

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" >
<ListView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<YourCustomView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>

Please try adding android:elevation attribute to your view in the XML. It will always place your custom view over the ListView.

Again: Views get placed to the layout in the order you add it. Question is: is it realy hidden or does it not render?. Check LogCat and Console for errors. If you only add this single Custom View to your layout, does it get rendered without any problems? If so, ensure you realy add your custom to the same parent view (group), as you add your ListView. If you don't get any further, provide de respective code sample.

Give an elevation to the view which you want to bring up.
android:elevation="2dp"

This works for me :
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="220dp"
android:gravity="bottom"
android:orientation="vertical"
android:theme="#style/ThemeOverlay.AppCompat.Dark">
<ImageView
android:id="#+id/details_wrapper"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:paddingBottom="16dip"
android:scaleType="centerCrop"
android:src="#drawable/temp_nav_image">
</ImageView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
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">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/nav_header_vertical_spacing"
android:text="Kapil Rajput"
android:textStyle="bold"
android:textColor="#android:color/black"
android:textAppearance="#style/TextAppearance.AppCompat.Body1"/>
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#android:color/black"
android:textStyle="bold"
android:text="kapil#gnxtsystems.com"/>
</LinearLayout>
</RelativeLayout>

I used relative layout and the order of the views somehow determines which one is on top.
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1">
<SeekBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:splitTrack="false"
android:layout_alignParentTop="true"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"/>
In this layout, the textview will be on top of the seekbar

Make parent view as relative layout and add your both view in xml.It wont work for Linear Layout.
And then add FirstView.bringToFront() programtically.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#mipmap/bg"
android:orientation="vertical"
android:padding="15dp">
<ImageView
android:id="#+id/imgIcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_gravity="center"
android:layout_marginBottom="-30dp"
android:layout_marginTop="30dp"
android:src="#mipmap/login_logo" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/imgIcon"
android:layout_gravity="bottom"
android:background="#B3FFFFFF"
android:gravity="center"
android:orientation="vertical"
android:paddingLeft="10dp"
android:paddingRight="10dp">
<View 1/>
<View 2/>
</LinearLayout>
Java file
imgIcon.brigtToFront();

what you should do is using android:layout_below or android:layout_above programmatically. so you should do this:
RelativeLayout.LayoutParams params= new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.BELOW, R.id.below_id);
viewToLayout.setLayoutParams(params);
and i suggest you take a look at this answer
hope this helps