Custom Spinner In Android

To create a custom spinner and change dropdown icon of your spinner, you have first created an xml spinner_bg.xml in drawable folder to be set as a spinner background. Here is the example of this - 

<?xml version="1.0"
    encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <layer-list>
            <item>
                <shape xmlns:android="http://schemas.android.com/apk/res/android"
                    android:shape="rectangle" android:padding="8dp">
                    <solid android:color="@color/colorAccent"/>
                    <corners
                        android:radius="4dp" />
                    <padding android:bottom="3dp"
                        android:left="3dp"
                        android:right="5dp"
                        android:top="3dp" />
                </shape>
            </item>
            <item>
                <bitmap android:gravity="center_vertical|right"
                    android:src="@mipmap/down_icon" />
                // you can use any other image here, instead of default_holo_dark_am
            </item>
        </layer-list>
    </item>
</selector>

Now create a style for your spinner in values>styles.xml file -

<style name="SpinnerTheme" parent="android:Widget.DeviceDefault.Spinner">
    <item name="android:background">@drawable/spinner_bg</item>
    <item name="android:padding">8dp</item>
    <item name="android:paddingTop">5dp</item>
    <item name="android:textSize">18sp</item>
    <item name="android:textColor">@android:color/white</item>
    <item name="android:paddingBottom">5dp</item>
    <item name="android:paddingRight">15dp</item>
</style>

Add this style in your spinner widget as -

<Spinner
    style="@style/SpinnerTheme"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:overlapAnchor="false" />



At the end, to change background color of popup, you have to set popup background color in your activity/fragment as- 

 ArrayAdapter adapter = new ArrayAdapter(context, R.layout.spinner_item, currencies);
            spinner.setAdapter(adapter);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                spinner.setPopupBackgroundResource(R.color.colorPrimary);
            }
 

Now you can run your application and see the customized spinner you have created.