Android Button Material Design With Image -

i use materialdesignlibrary

i want use image

<com.gc.materialdesign.views.buttonflat                 android:id="@+id/buttonflat"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:background="#1e88e5"                 android:text="button" /> 

how can that?

<com.gc.materialdesign.views.buttonflat             android:id="@+id/buttonflat"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:background="#1e88e5"             android:background-image="src=<src>"             android:text="button" />