add close button on right top corner of alert dialog box for android
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="400dp"
android:layout_alignParentTop="true"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="15dp"
android:background="#F4F4F4">
<!--Main Body of your custom dialog-->
</RelativeLayout>
<LinearLayout
android:id="@+id/llTop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:orientation="vertical">
<ImageButton
android:id="@+id/btnCancel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/btnBookK"
android:background="@null"
android:src="@drawable/ic_close" />
</LinearLayout>
</RelativeLayout>