Android Tutorial => How to add the FAB to the layout

Example

To use a FloatingActionButton just add the dependency in the build.gradle file as described in the remarks section.

Then add to the layout:

 <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@drawable/my_icon" />

An example:

Color

The background color of this view defaults to the your theme's colorAccent.

In the above image if the src only points to + icon (by default 24x24 dp),to get the background color of full circle you can use app:backgroundTint="@color/your_colour"

If you wish to change the color in code you can use,

myFab.setBackgroundTintList(ColorStateList.valueOf(your color in int));

If you want to change FAB's color in pressed state use

mFab.setRippleColor(your color in int);

Positioning

It is recommended to place 16dp minimum from the edge on mobile,and 24dp minimum on tablet/desktop.

Note : Once you set an src excepting to cover the full area of FloatingActionButton make sure you have the right size of that image to get the best result.

Default circle size is 56 x 56dp