incoming_call_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    android:id="@+id/RelativeLayout01"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android"
android:background="@drawable/call_bg">

<RelativeLayout
    android:id="@+id/callInfoLayout"
    android:layout_width="match_parent"
    android:paddingTop="33dp"
    android:paddingStart="30dp"
    android:paddingEnd="30dp"
    android:layout_height="193dp">

    <TextView
        android:id="@+id/callStatus"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/incoming_call"
        android:textColor="@color/black"
        android:textSize="20sp"
        android:gravity="center"
        />

    <TextView
        android:id="@+id/callerName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/black"
        android:textSize="40sp"
        android:layout_below="@+id/callStatus"
        android:fontFamily="sans-serif-light"
        android:gravity="center"
        />

</RelativeLayout>

<FrameLayout
    android:id="@+id/callActionLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/callInfoLayout">

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical"
        android:paddingHorizontal="50dp"
        android:paddingVertical="60dp"
        android:gravity="bottom" >


        <RelativeLayout
            android:id="@+id/relativeLayout1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">

        <ImageButton
            android:id="@+id/reject_call_btn"
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:scaleType="fitCenter"
            android:background="@null"
            android:src="@drawable/rjt_btn"
            android:layout_alignParentRight="true"
         />

        <ImageButton
            android:id="@+id/accept_call_btn"
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:background="@null"
            android:scaleType="fitCenter"
            android:layout_alignParentLeft="true"
            android:src="@drawable/acpt_btn" />
        </RelativeLayout>

       </LinearLayout>



</FrameLayout>

</RelativeLayout>