How to create Button Image in android

How to create Button Image in android:

Activity_main.xml

<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context=".MainActivity">

<LinearLayout

android:id="@+id/linearLayout1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:layout_marginLeft="100dp"

android:layout_marginTop="96dp"

android:orientation="vertical">

</LinearLayout>

<Button

android:id="@+id/etTestBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_below="@+id/linearLayout1"

android:layout_centerHorizontal="true"

android:onClick="test"

android:layout_marginTop="20dp"

android:text="Test"/>

<Button

android:id="@+id/etbtnNormal"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/etTestBtn"

android:layout_below="@+id/etTestBtn"

android:background="@drawable/button_normal"

android:onClick="normalPressed"

android:text=""/>

</RelativeLayout>

MainActivity.java

<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context=".MainActivity">

<LinearLayout

android:id="@+id/linearLayout1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:layout_marginLeft="100dp"

android:layout_marginTop="96dp"

android:orientation="vertical">

</LinearLayout>

<Button

android:id="@+id/etTestBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_below="@+id/linearLayout1"

android:layout_centerHorizontal="true"

android:onClick="test"

android:layout_marginTop="20dp"

android:text="Test"/>

<Button

android:id="@+id/etbtnNormal"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/etTestBtn"

android:layout_below="@+id/etTestBtn"

android:background="@drawable/button_normal"

android:onClick="normalPressed"

android:text=""/>

</RelativeLayout>

Button_normal(res/create drawable folder)

<?xmlversion="1.0"encoding="utf-8"?>

<selectorxmlns:android="http://schemas.android.com/apk/res/android" >

<itemandroid:drawable="@drawable/btn_focus" android:state_focused="true"/>

<itemandroid:drawable="@drawable/btn_normal"android:state_pressed="true"/>

<itemandroid:drawable="@drawable/btn_sattar"/>

</selector>