Vector drawables overview

Key points

A vector drawable is a vector graphic defined in an XML file as a set of points, lines, and curves along with its associated color information.
Vector drawables are scalable, meaning they can be resized without loss of display quality. This makes them ideal for use in Android apps, as it can help to reduce the size of your APK files and improve performance.
You can create vector drawables in Android Studio by right-clicking on the drawable folder in your project and selecting New > Vector Asset. You can also import SVG files into Android Studio as vector drawables.

Summary generated by Google Bard on 24 July, 2023

Introduction

A VectorDrawable is a vector graphic defined in an XML file as a set of points, lines, and curves along with its associated color information. The major advantage of using a vector drawable is image scalability. It can be scaled without loss of display quality, which means the same file is resized for different screen densities without loss of image quality. This results in smaller APK files and less developer maintenance. You can also use vector images for animation by using multiple XML files instead of multiple images for each display resolution.

This page and the video below provide an overview of how to create vector drawables in XML. Android Studio can also convert SVG files to the vector drawable format, as described in using Add multi-density vector graphics.

Android 5.0 (API level 21) was the first version to officially support vector drawables with VectorDrawable and AnimatedVectorDrawable, but you can support older versions with the Android support library, which provides the VectorDrawableCompat and AnimatedVectorDrawableCompat classes.

About VectorDrawable class

VectorDrawable defines a static drawable object. Similar to the SVG format, each vector graphic is defined as a tree hierarchy, which is made up of path and group objects. Each path contains the geometry of the object's outline and group contains details for transformation. All paths are drawn in the same order as they appear in the XML file.

Figure 1. Sample hierarchy of a vector drawable asset

The Vector asset studio tool offers a simple way to add a vector graphic to the project as an XML file.

Example XML

Here is a sample VectorDrawable XML file that renders an image of a battery in the charging mode.

<!-- res/drawable/battery_charging.xml -->
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:height="24dp"
    android:width="24dp"
    android:viewportWidth="24.0"
    android:viewportHeight="24.0">
   <group
         android:name="rotationGroup"
         android:pivotX="10.0"
         android:pivotY="10.0"
         android:rotation="15.0" >
      <path
        android:name="vect"
        android:fillColor="#FF000000"
        android:pathData="M15.67,4H14V2h-4v2H8.33C7.6,4 7,4.6 7,5.33V9h4.93L13,7v2h4V5.33C17,4.6 16.4,4 15.67,4z"
        android:fillAlpha=".3"/>
      <path
        android:name="draw"
        android:fillColor="#FF000000"
        android:pathData="M13,12.5h2L11,20v-5.5H9L11.93,9H7v11.67C7,21.4 7.6,22 8.33,22h7.33c0.74,0 1.34,-0.6 1.34,-1.33V9h-4v3.5z"/>
   </group>
</vector>

This XML renders the following image:

About AnimatedVectorDrawable class

AnimatedVectorDrawable adds animation to the properties of a vector graphic. You can define an animated vector graphic as three separate resource files or as a single XML file defining the entire drawable. Let's look at both the approaches for better understanding: Multiple XML files and Single XML file.

Multiple XML files

By using this approach, you can define three separate XML files:

A VectorDrawable XML file.
An AnimatedVectorDrawable XML file that defines the target VectorDrawable, the target paths and groups to animate, the properties, and the animations defined as ObjectAnimator objects or AnimatorSet objects.
An animator XML file.

Example of multiple XML files

The following XML files demonstrate the animation of a vector graphic.

VectorDrawable's XML file: vd.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
   android:height="64dp"
   android:width="64dp"
   android:viewportHeight="600"
   android:viewportWidth="600" >
   <group
      android:name="rotationGroup"
      android:pivotX="300.0"
      android:pivotY="300.0"
      android:rotation="45.0" >
      <path
         android:name="vectorPath"
         android:fillColor="#000000"
         android:pathData="M300,70 l 0,-70 70,70 0,0 -70,70z" />
   </group>
</vector>

AnimatedVectorDrawable's XML file: avd.xml

<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
   android:drawable="@drawable/vd" >
     <target
         android:name="rotationGroup"
         android:animation="@anim/rotation" />
     <target
         android:name="vectorPath"
         android:animation="@anim/path_morph" />
</animated-vector>

Animator XML files that are used in the AnimatedVectorDrawable's XML file: rotation.xml and path_morph.xml

<objectAnimator
   android:duration="6000"
   android:propertyName="rotation"
   android:valueFrom="0"
   android:valueTo="360" />

<set xmlns:android="http://schemas.android.com/apk/res/android">
   <objectAnimator
      android:duration="3000"
      android:propertyName="pathData"
      android:valueFrom="M300,70 l 0,-70 70,70 0,0   -70,70z"
      android:valueTo="M300,70 l 0,-70 70,0  0,140 -70,0 z"
      android:valueType="pathType"/>
</set>

Single XML file

By using this approach, you can merge the related XML files into a single XML file through the XML Bundle Format. At the time of building the app, the aapt tag creates separate resources and references them in the animated vector. This approach requires Build Tools 24 or higher, and the output is backward compatible.

Example of a single XML file

<animated-vector
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt">
    <aapt:attr name="android:drawable">
        <vector
            android:width="24dp"
            android:height="24dp"
            android:viewportWidth="24"
            android:viewportHeight="24">
            <path
                android:name="root"
                android:strokeWidth="2"
                android:strokeLineCap="square"
                android:strokeColor="?android:colorControlNormal"
                android:pathData="M4.8,13.4 L9,17.6 M10.4,16.2 L19.6,7" />
        </vector>
    </aapt:attr>
    <target android:name="root">
        <aapt:attr name="android:animation">
            <objectAnimator
                android:propertyName="pathData"
                android:valueFrom="M4.8,13.4 L9,17.6 M10.4,16.2 L19.6,7"
                android:valueTo="M6.4,6.4 L17.6,17.6 M6.4,17.6 L17.6,6.4"
                android:duration="300"
                android:interpolator="@android:interpolator/fast_out_slow_in"
                android:valueType="pathType" />
        </aapt:attr>
    </target>
</animated-vector>

Vector drawables backward compatibility solution

To support vector drawable and animated vector drawable on devices running platform versions lower than Android 5.0 (API level 21), or use fillColor, fillType and strokeColor functionalities below Android 7.0 (API level 24), VectorDrawableCompat and AnimatedVectorDrawableCompat are available through two support libraries: support-vector-drawable and animated-vector-drawable, respectively.

Android Studio 1.4 introduced limited compatibility support for vector drawables by generating PNG files at build time. However, the vector drawable and animated vector drawable support Libraries offer both flexibility and broad compatibility — it's a support library, so you can use it with all Android platform versions back to Android 2.1 (API level 7+). To configure your app to use vector support libraries, add the vectorDrawables element to your build.gradle file in the app module.

Use the following code snippet to configure the vectorDrawables element:

Groovy

// For Gradle Plugin 2.0+
android {
    defaultConfig {
        vectorDrawables.useSupportLibrary = true
    }
}

Kotlin

// For Gradle Plugin 2.0+
android {
    defaultConfig {
        vectorDrawables.useSupportLibrary = true
    }
}

Groovy

// For Gradle Plugin 1.5 or below
android {
    defaultConfig {
        // Stops the Gradle plugin’s automatic rasterization of vectors
        generatedDensities = []
    }
    // Flag notifies aapt to keep the attribute IDs around
    aaptOptions {
        additionalParameters "--no-version-vectors"
    }
}

Kotlin

// For Gradle Plugin 1.5 or below
android {
    defaultConfig {
        // Stops the Gradle plugin’s automatic rasterization of vectors
        generatedDensities()
    }
    // Flag notifies aapt to keep the attribute IDs around
    aaptOptions {
        additionalParameters("--no-version-vectors")
    }
}

You can use VectorDrawableCompat and AnimatedVectorDrawableCompat on all on devices running Android 4.0 (API level 14) and higher. The way Android loads drawables, not every place that accepts a drawable ID, such as in an XML file, supports loading vector drawables. The android.support.v7.appcompat package has added a number of features to make it easy to use vector drawables. Firstly, when you use android.support.v7.appcompat package with ImageView or with subclasses such as ImageButton and FloatingActionButton, you can use the new app:srcCompat attribute to reference vector drawables as well as any other drawable available to android:src:

<ImageView
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  app:srcCompat="@drawable/ic_add" />

To change drawables at runtime, you can use the setImageResource() method as before. Using AppCompat and app:srcCompat is the most foolproof method of integrating vector drawables into your app.

Support Library 25.4.0 and higher supports the following features:

Path Morphing (PathType evaluator) Used to morph one path into another path.
Path Interpolation Used to define a flexible interpolator (represented as a path) instead of the system-defined interpolators like LinearInterpolator.

Support Library 26.0.0-beta1 and higher supports the following features:

Move along path The geometry object can move around, along an arbitrary path, as part of an animation.

Example of multiple XML files using the support library

The following XML files demonstrate the approach of using multiple XML files to animate a vector graphic.

VectorDrawable's XML file: vd.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
   android:height="64dp"
   android:width="64dp"
   android:viewportHeight="600"
   android:viewportWidth="600" >
   <group
      android:name="rotationGroup"
      android:pivotX="300.0"
      android:pivotY="300.0"
      android:rotation="45.0" >
      <path
         android:name="vectorPath"
         android:fillColor="#000000"
         android:pathData="M300,70 l 0,-70 70,70 0,0 -70,70z" />
   </group>
</vector>

AnimatedVectorDrawable's XML file: avd.xml

<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
   android:drawable="@drawable/vd" >
     <target
         android:name="rotationGroup"
         android:animation="@anim/rotation" />
</animated-vector>

Animator XML file that is used in the AnimatedVectorDrawable's XML file: rotation.xml

<objectAnimator
   android:duration="6000"
   android:propertyName="rotation"
   android:valueFrom="0"
   android:valueTo="360" />

Single XML file

The following XML file demonstrates the approach of using a single XML file to animate a vector graphic. At the time of building the app, the aapt tag creates separate resources and references them in the animated vector. This approach requires Build Tools 24 or higher, and the output is backward compatible.

Example of a single XML file using the support library

<animated-vector
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt">
    <aapt:attr name="android:drawable">
        <vector xmlns:android="http://schemas.android.com/apk/res/android"
            android:width="64dp"
            android:height="64dp"
            android:viewportWidth="600"
            android:viewportHeight="600">
            <group
                android:name="rotationGroup"
                android:pivotX="300"
                android:pivotY="300"
                android:rotation="45.0" >
                <path
                    android:name="vectorPath"
                    android:fillColor="#000000"
                    android:pathData="M300,70 l 0,-70 70,70 0,0 -70,70z" />
            </group>
        </vector>
    </aapt:attr>
    <target android:name="rotationGroup">
        <aapt:attr name="android:animation">
            <objectAnimator
                android:propertyName="rotation"
                android:valueFrom="0"
                android:valueTo="360"
                android:duration="6000"
                android:interpolator="@android:interpolator/fast_out_slow_in" />
        </aapt:attr>
    </target>
</animated-vector>