<ImageButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/plusOneButton"
            android:layout_marginBottom="5dp"
            android:src="@drawable/thinking"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:background="@drawable/button_border"
            />

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    >
    <stroke
        android:width="30dp"
        android:color="#ff000000" />
    <padding
        android:left="1dp"
        android:top="1dp"
        android:right="1dp"
        android:bottom="1dp" />

</shape>