Android View shadow

I know this question has already been answered but I want you to know that I found a drawable on Android Studio that is very similar to the pics you have in the question: Take a look at this:

android:background="@drawable/abc_menu_dropdown_panel_holo_light"

It looks like this:

Hope it will be helpful

Edit

The option above is for the older versions of Android Studio so you may not find it. For newer versions:

android:background="@android:drawable/dialog_holo_light_frame"

Moreover, if you want to have your own custom shape, I suggest to use a drawing software like Photoshop and draw it.

Don't forget to save it as .9.png file (example: my_background.9.png)

Read the documentation: Draw 9-patch

Edit 2

An even better and less hard working solution is to use a CardView and set app:cardPreventCornerOverlap="false" to prevent views to overlap the borders:

<android.support.v7.widget.CardView
    android:id="@+id/card_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardCornerRadius="2dp"
    app:cardElevation="2dp"
    app:cardPreventCornerOverlap="false"
    app:contentPadding="0dp">

    <!-- your layout stuff here -->

</android.support.v7.widget.CardView>

Also make sure to have included the latest version in the build.gradle, current is

compile 'com.android.support:cardview-v7:26.0.0'

I'm using Android Studio 0.8.6 and I couldn't find:

android:background="@drawable/abc_menu_dropdown_panel_holo_light"

so I found this instead:

android:background="@android:drawable/dialog_holo_light_frame"

and it looks like this:

putting a background of @android:drawable/dialog_holo_light_frame, gives shadow but you can't change background color nor border style, so it's better to benefit from the shadow of it, while still be able to put a background via layer-list

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <!--the shadow comes from here-->
    <item
        android:bottom="0dp"
        android:drawable="@android:drawable/dialog_holo_light_frame"
        android:left="0dp"
        android:right="0dp"
        android:top="0dp">

    </item>

    <item
        android:bottom="0dp"
        android:left="0dp"
        android:right="0dp"
        android:top="0dp">
        <!--whatever you want in the background, here i preferred solid white -->
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white" />

        </shape>
    </item>
</layer-list>

save it in the drawable folder under say shadow.xml

to assign it to a view, in the xml layout file set the background of it

android:background="@drawable/shadow"

Create card_background.xml in the res/drawable folder with the following code:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item>
    <shape android:shape="rectangle">
        <solid android:color="#BDBDBD"/>
        <corners android:radius="5dp"/>
    </shape>
</item>

<item
    android:left="0dp"
    android:right="0dp"
    android:top="0dp"
    android:bottom="2dp">
    <shape android:shape="rectangle">
        <solid android:color="#ffffff"/>
        <corners android:radius="5dp"/>
    </shape>
</item>
</layer-list>

Then add the following code to the element to which you want the card layout

android:background="@drawable/card_background"

the following line defines the color of the shadow for the card

<solid android:color="#BDBDBD"/>

Use elevation property to achieve a shadow affect:

<View ...
    android:elevation="2dp"/>

This is only to be used past v21, check out this link: http://developer.android.com/training/material/shadows-clipping.html