Building the app for release

You have two possible release formats when publishing to the Play Store.

• App bundle (preferred)
• APK

Build an app bundle

This section describes how to build a release app bundle. If you completed the signing steps, the app bundle will be signed. At this point, you might consider obfuscating your Dart code to make it more difficult to reverse engineer. Obfuscating your code involves adding a couple of flags to your build command, and maintaining additional files to de-obfuscate stack traces.

From the command line:

1. Enter cd [project]
2. Run flutter build appbundle –build-number=1 –build-name=1.00
   (Running flutter build defaults to a release build.)

The release bundle for your app is created at [project]/build/app/outputs/bundle/release/app.aab.

By default, the app bundle contains your Dart code and the Flutter runtime compiled for armeabi-v7a (ARM 32-bit), arm64-v8a (ARM 64-bit), and x86-64 (x86 64-bit).

Test the app bundle

An app bundle can be tested in multiple ways—this section describes two.

Offline using the bundle tool

1. If you haven’t done so already, download bundletool from the GitHub repository.
2. Generate a set of APKs from your app bundle.
3. Deploy the APKs to connected devices.

Online using Google Play

1. Upload your bundle to Google Play to test it. You can use the internal test track, or the alpha or beta channels to test the bundle before releasing it in production.
2. Follow these steps to upload your bundle to the Play Store.

Build an APK

Although app bundles are preferred over APKs, there are stores that don’t yet support app bundles. In this case, build a release APK for each target ABI (Application Binary Interface).

If you completed the signing steps, the APK will be signed. At this point, you might consider obfuscating your Dart code to make it more difficult to reverse engineer. Obfuscating your code involves adding a couple of flags to your build command.

From the command line:

1. Enter cd [project]
2. Run flutter build apk --split-per-abi –build-number=1 –build-name=1.00
   (The flutter build command defaults to --release.)

This command results in three APK files:

• [project]/build/app/outputs/apk/release/app-armeabi-v7a-release.apk
• [project]/build/app/outputs/apk/release/app-arm64-v8a-release.apk
• [project]/build/app/outputs/apk/release/app-x86_64-release.apk

Removing the --split-per-abi flag results in a fat APK that contains your code compiled for all the target ABIs. Such APKs are larger in size than their split counterparts, causing the user to download native binaries that are not applicable to their device’s architecture.

Install an APK on a device

Follow these steps to install the APK on a connected Android device.

From the command line:

1. Connect your Android device to your computer with a USB cable.
2. Enter cd [project].
3. Run flutter install.

Publishing to the Google Play Store

For detailed instructions on publishing your app to the Google Play Store, see the Google Play launch documentation.