CardView is a member of the Android Support Library, and provides a layout for cards.

To add CardView to your project, add the following line to your build.gradle dependencies.

compile 'com.android.support:cardview-v7:25.1.1'

A number of the latest version may be found here

In your layout you can then add the following to get a card.

<android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <!-- one child layout containing other layouts or views -->     

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

You can then add other layouts inside this and they will be encompassed in a card.

Also, CardView can be populated with any UI element and manipulated from code.

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/card_view"
    android:layout_margin="5dp"
    card_view:cardBackgroundColor="#81C784"
    card_view:cardCornerRadius="12dp"
    card_view:cardElevation="3dp"
    card_view:contentPadding="4dp" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="16dp" >

        <ImageView
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:id="@+id/item_image"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:layout_marginRight="16dp"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/item_title"
            android:layout_toRightOf="@+id/item_image"
            android:layout_alignParentTop="true"
            android:textSize="30sp"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/item_detail"
            android:layout_toRightOf="@+id/item_image"
            android:layout_below="@+id/item_title"
            />

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

CardView provides a default elevation and corner radius so that cards have a consistent appearance across the platforms.

You can customize these default values using these attributes in the xml file:

1. card_view:cardElevation attribute add elevation in CardView.
2. card_view:cardBackgroundColor attribute is used to customize background color of CardView's background(you can give any color).
3. card_view:cardCornerRadius attribute is used to curve 4 edges of CardView
4. card_view:contentPadding attribute add padding between card and children of card

Note: card_view is a namespace defined in topmost parent layout view. xmlns:card_view="http://schemas.android.com/apk/res-auto"

Here an example:

<android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        card_view:cardElevation="4dp"
        card_view:cardBackgroundColor="@android:color/white"
        card_view:cardCornerRadius="8dp"
        card_view:contentPadding="16dp">

        <!-- one child layout containing other layouts or views -->     

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

You can also do it programmatically using:

card.setCardBackgroundColor(....);
card.setCardElevation(...);
card.setRadius(....);
card.setContentPadding();

Check the official javadoc for additional properties.

To enable the ripple animation in a CardView, add the following attributes:

<android.support.v7.widget.CardView
  ...
  android:clickable="true"
  android:foreground="?android:attr/selectableItemBackground">
  ...
</android.support.v7.widget.CardView>

While using Image/Colour as an background in a CardView, You might end up with slight white paddings (If default Card colour is white) on the edges. This occurs due to the default rounded corners in the Card View. Here is how to avoid those margins in Pre-lollipop devices.

We need to use an attribute card_view:cardPreventCornerOverlap="false" in the CardView. 1). In XML use the following snippet.

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    card_view:cardPreventCornerOverlap="false"
    android:layout_height="wrap_content"> 
      <ImageView
            android:id="@+id/row_wallet_redeem_img"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:adjustViewBounds="true"
            android:scaleType="centerCrop"
            android:src="@drawable/bg_image" />

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

2. In Java like this cardView.setPreventCornerOverlap(false).

Doing so removes an unwanted padding on the Card's edges. Here are some visual examples related to this implementation.

1 Card with image background in API 21 (perfectly fine)

2 Card with image background in API 19 without attribute (notice the paddings around image)

3 FIXED Card with image background in API 19 with attribute cardView.setPreventCornerOverlap(false) (Issue now fixed)

Also read about this on Documentation here
Original SOF post here

public void setCardColorTran(CardView card) {
    ColorDrawable[] color = {new ColorDrawable(Color.BLUE), new ColorDrawable(Color.RED)};
    TransitionDrawable trans = new TransitionDrawable(color);
    if(Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {
        card.setBackground(trans);
    } else {
        card.setBackgroundDrawable(trans);
    }
    trans.startTransition(5000);
}