Change colour of small triangle on spinner in android

How can I change the colour of small triangle at the bottom right corner of spinner like shown in the image? It is showing default grey colour right now. like this

The best and easiest solution:

spinner.getBackground().setColorFilter(getResources().getColor(R.color.red), PorterDuff.Mode.SRC_ATOP);

Other solution (Thanks to Simon) if you don't want change all Spinners:

Drawable spinnerDrawable = spinner.getBackground().getConstantState().newDrawable();

spinnerDrawable.setColorFilter(getResources().getColor(R.color.red), PorterDuff.Mode.SRC_ATOP);

if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
    spinner.setBackground(spinnerDrawable);
}else{
    spinner.setBackgroundDrawable(spinnerDrawable);
}

From Lollipop on, you can set the background tint on xml,

android:backgroundTint="@color/my_color"

To get the correct images, you can go to Android Asset Studio site and choose the Android Holo Colors Generator. This will create all the assets you might need, including the "triangle". It also generates the XML files that implement the changes.

Here are the example XML files:

Custom Color:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="apptheme_color">#33b5e5</color>
</resources>

Custom Spinner Style:

<?xml version="1.0" encoding="utf-8"?>

<!-- Generated with http://android-holo-colors.com -->
<resources xmlns:android="http://schemas.android.com/apk/res/android">

  <style name="SpinnerAppTheme" parent="android:Widget.Spinner">
      <item name="android:background">@drawable/apptheme_spinner_background_holo_light</item>
      <item name="android:dropDownSelector">@drawable/apptheme_list_selector_holo_light</item>
  </style>

  <style name="SpinnerDropDownItemAppTheme" parent="android:Widget.DropDownItem.Spinner">
      <item name="android:checkMark">@drawable/apptheme_btn_radio_holo_light</item>
  </style>
</resources>

Custom Application Theme:

<?xml version="1.0" encoding="utf-8"?>

<!-- Generated with http://android-holo-colors.com -->
<resources xmlns:android="http://schemas.android.com/apk/res/android">

  <style name="AppTheme" parent="@style/_AppTheme"/>

  <style name="_AppTheme" parent="Theme.AppCompat.Light">

    <item name="android:spinnerStyle">@style/SpinnerAppTheme</item>

    <item name="android:spinnerDropDownItemStyle">@style/SpinnerDropDownItemAppTheme</item>

  </style>

</resources>

As you can see, there are also many drawables that are referenced by these styles.

Here is the one specific to the "triangle" you want to change:

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2010 The Android Open Source Project

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_enabled="false"
          android:drawable="@drawable/apptheme_spinner_disabled_holo_light" />
    <item android:state_pressed="true"
          android:drawable="@drawable/apptheme_spinner_pressed_holo_light" />
    <item android:state_pressed="false" android:state_focused="true"
          android:drawable="@drawable/apptheme_spinner_focused_holo_light" />
    <item android:drawable="@drawable/apptheme_spinner_default_holo_light" />
</selector>

I don't think this is the right place to list every file completely, since you can get them all directly from the referenced tool.

Note: this is the way to theme your whole app so that all spinners are updated to the custom style.

If you are looking for a quick and dirty way to change just one spinner, then check out that article referenced by Ricky in his comment:

• Android: Custom Spinners by Tom Gersic

I recommend reading it anyway, because it explains the process very well, and will help you to understand the rest of my answer.

I'm still very new at Android development, so perhaps take my advice with a grain of salt, but none of the answers here seemed to relate to the spinner implementation I was using.

What I was looking for

android:backgroundTint="@color/colorPrimary"

Here's the entire <Spinner> tag:

        <Spinner
            android:id="@+id/coin_selector"
            android:layout_width="wrap_content"
            android:layout_height="21dp"
            android:layout_margin="26dp"
            android:layout_weight="1"
            android:textColor="#FFFFFF"
            android:dropDownSelector="@color/colorAccent"
            android:backgroundTint="@color/colorPrimary"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            tools:layout_editor_absoluteY="89dp"/>

Here is other way to resolve that programatically as well. (Tested on API 19 & Above).

Use ViewCompat for this.

ViewCompat.setBackgroundTintList(spinner, ColorStateList.valueOf(your_color));

Usage of spinner.setSupportBackgroundTintList throws an error