[android] How to set dropdown arrow in spinner?

Copy and paste this xml to show as a Dropdown and change your Dropdown color

 <?xml version="1.0" encoding="UTF-8"?><RelativeLayout xmlns: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:background="@drawable/back1"
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="55dp"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:layout_marginTop="20dp" 
    android:background="@drawable/red">

    <Spinner android:id="@+id/spinner1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:dropDownWidth="fill_parent" 
        android:popupBackground="@drawable/textbox"
        android:spinnerMode="dropdown"
        android:background="@drawable/drop_down_large"

     />

</LinearLayout>

<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="55dp"
    android:layout_alignLeft="@+id/linearLayout1"
    android:layout_alignRight="@+id/linearLayout1"
    android:layout_below="@+id/linearLayout1"
    android:layout_marginTop="25dp"
    android:background="@drawable/red"
    android:ems="10"
    android:hint="enter card number" >

    <requestFocus />
</EditText>

<LinearLayout
    android:id="@+id/linearLayout2"
    android:layout_width="wrap_content"
    android:layout_height="55dp"
    android:layout_alignLeft="@+id/editText1"
    android:layout_alignRight="@+id/editText1"
    android:layout_below="@+id/editText1"
    android:layout_marginTop="33dp"
    android:orientation="horizontal" 
    android:background="@drawable/red">

    <Spinner
        android:id="@+id/spinner3"
        android:layout_width="72dp"
        android:layout_height="wrap_content"
         android:popupBackground="@drawable/textbox"
        android:spinnerMode="dropdown"
        android:background="@drawable/drop_down_large"
         />

    <Spinner
        android:id="@+id/spinner2"
        android:layout_width="72dp"
        android:layout_height="wrap_content" 
        android:popupBackground="@drawable/textbox"
        android:spinnerMode="dropdown"
        android:background="@drawable/drop_down_large"
        />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="22dp"
        android:layout_height="match_parent"
        android:layout_weight="0.18"
        android:ems="10"
        android:hint="enter cvv" />

</LinearLayout>

<LinearLayout
    android:id="@+id/linearLayout3"
    android:layout_width="wrap_content"
    android:layout_height="55dp"
    android:layout_alignParentLeft="true"
    android:layout_alignRight="@+id/linearLayout2"
    android:layout_below="@+id/linearLayout2"
    android:layout_marginTop="26dp"
    android:orientation="vertical"
    android:background="@drawable/red" >
</LinearLayout>

<Spinner
    android:id="@+id/spinner4"
    android:layout_width="15dp"
    android:layout_height="18dp"
    android:layout_alignBottom="@+id/linearLayout3"
    android:layout_alignLeft="@+id/linearLayout3"
    android:layout_alignRight="@+id/linearLayout3"
    android:layout_alignTop="@+id/linearLayout3"
    android:popupBackground="@drawable/textbox"
        android:spinnerMode="dropdown"
        android:background="@drawable/drop_down_large"/>

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/linearLayout3"
    android:layout_marginTop="18dp"
    android:text="Add Amount"
    android:background="@drawable/buttonsty"/>