How to update Android app programmatically?
Updating an Android app programmatically means using code to manage the update process rather than relying solely on the Google Play Store. This allows developers to have more control and implement custom logic around app updates. There are several benefits to updating apps programmatically:
First, it enables performing gradual rollouts of updates to subsets of users. This is useful for testing out changes with a small percentage of the userbase before rolling out more widely in case issues emerge. Programmatic updates support A/B testing new features and experimenting safely.
Second, programmatic updates allow prompting users to update an app and guiding them seamlessly through the process. Rather than hoping users will update via the Play Store manually, developers can notify users, take them directly to the latest version, and improve the experience.
Third, developers can implement custom checks around updates such as forcing critical security patches or requiring users to update before accessing new functionality. This gives developers more oversight around important updates.
Finally, programmatic updates allow delivering updates dynamically based on user segmentation and targeting. Developers can customize and tailor the update experience on a granular level.
By leveraging programmatic updates, developers can go beyond the basic Play Store flow and craft smart, automated experiences that benefit both users and developers.
Prerequisites
Before beginning to programmatically update Android apps, you’ll need a solid foundation in Android development basics and experience working with Java or Kotlin. Some key prerequisites include:
– Proficiency in Java or Kotlin programming. You’ll need to be comfortable writing code in one of these core Android languages to implement update functionality. Check out Android’s documentation on getting started with Java or Kotlin if you need a refresher.
– Understanding of core Android concepts like Activities, Services, BroadcastReceivers, etc. You’ll need to work with these components to check for updates, download new APK files, and trigger updates.
– Familiarity with Android SDK tools like Gradle, Android Studio/IntelliJ IDEA, ADB, etc. These tools will be key for building, versioning, and testing your app updates.
– Basic knowledge of REST APIs and HTTP networking. Most apps will retrieve update metadata and APK files from a server API.
– Experience building, running, and debugging Android apps. Updating an existing app builds on these fundamentals.
With solid Android dev skills and some app development experience, you’ll be well prepared to implement programmatic updates. Check the recommended learning resources if you need to strengthen your skills.
Project Setup
Gradle is the build system for Android Studio projects. To get started, you’ll need to have Android Studio installed with the latest Android SDK and tools. Android Studio bundles the Gradle plugin so you don’t need to install it separately.
When you create a new Android Studio project, it generates the basic Gradle config files needed for building and running your app. These include the top-level build.gradle file which defines the Gradle version and repositories, as well as the module-level build.gradle that configures the Android plugin and dependencies for that module.
Android Studio provides a graphical interface for managing Gradle builds, but you can also edit the config files directly. The key files and directories include:
- build.gradle – Top-level build config
- app/build.gradle – Module build config
- gradle/ – Gradle wrapper files
- gradle.properties – Gradle properties/settings
With this basic Gradle configuration, you can build, run, and debug your Android app project using the tasks and options available in Android Studio and on the command line. As you add more features and functionality, you may need to modify the Gradle build scripts and dependencies.
Overall, Android Studio and Gradle provide a flexible system for automating and customizing builds for your Android applications. The IDE integration makes it easy to get started, while also allowing you to tap into more advanced capabilities via the Gradle config files.
Versioning
Semantic versioning is an industry standard for version numbering that defines a specific meaning and progression for each component of a version number. For Android apps, using semantic versioning allows developers to clearly communicate the scope and impact of app updates to users.
Semantic version numbers take the form of X.Y.Z where:
- X stands for the major version
- Y stands for the minor version
- Z stands for the patch version
According to the semantic versioning specification (https://semver.org/), incrementing each component has a specific meaning:
- Major version X should be incremented for incompatible API changes
- Minor version Y should be incremented for new backwards-compatible functionality
- Patch version Z should be incremented for backwards-compatible bug fixes
For example, increasing the app version from 1.2.3 to 2.0.0 signals there are major changes, while going from 1.2.3 to 1.3.0 indicates a minor new feature, and 1.2.3 to 1.2.4 is just a bug fix update.
Using semantic versioning clearly communicates to users the scope of changes in app updates. It also helps developers manage releases and set expectations for the impact of upgrades.
Build Types and Flavors
Build types and flavors allow you to create different versions of your app from a single codebase. Build types are used to create different binaries for testing, staging, and production environments. Flavors let you create variations of your app, such as a free and paid version.
To configure build types and flavors, open the app level build.gradle file and add the following:
For build types:
android {
...
buildTypes {
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
debug {
minifyEnabled false
}
}
}
This defines a release and debug build type. Release builds are minified and use ProGuard, while debug builds are not minified.
For product flavors:
android {
...
productFlavors {
free {
applicationId "com.example.myapp.free"
}
paid {
applicationId "com.example.myapp.paid"
}
}
}
This defines a free and paid flavor. Each flavor has a different application ID to distinguish them.
You can now build your app using the various build types and flavors, such as:
./gradlew assembleFreeRelease
To build the free flavor’s release binary. See this guide for more details on configuring build types and flavors.
Creating Update Tasks
One way to enable app updates programmatically is by creating custom Gradle tasks in your app’s build.gradle file. These tasks can handle checking the latest version, downloading updates, and more.
To implement version checks, you can create a task like:
task checkForUpdates {
def latestVersion = // check latest version from server
if (latestVersion > versionName) {
// update available
}
}
This checks the versionName property against the latest version on your server. You can call tasks like this from your app code to look for updates.
For downloading updates, Gradle provides useful methods like copy and unzip. You can create tasks like:
task downloadUpdate {
// download update zip
copy {
from 'updates/app-v2.zip'
into 'build/updates'
}
// unzip
unzip {
from 'build/updates/app-v2.zip'
into 'build/updates'
}
}
This will download and unzip the update file into the build folder. You can then access it from code to install the update.
Overall, Gradle provides a flexible way to script update workflows. See the Android Gradle plugin release notes for updating to the latest version.
Implementing Checks
Before downloading and installing an update, your app will need to check the currently installed version against the latest available version. The easiest way to do this is by comparing the versionName or versionCode values in the build.gradle file or AndroidManifest.xml against a remote version file or API response.
For example, you can make a request to your backend to get the latest version details and compare it to the current build version using code like this:
String currentVersion = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
JsonObject latestVersionResponse = // request to backend API
if (latestVersionResponse.versionName > currentVersion) {
// Proceed with update
}
Alternatively, you may host a version.json file on your server that your app can download and parse to check the versionName. For example:
{
"latestVersion": "1.2.3"
}
Then compare this to the current versionName to determine if an update is needed. Focusing on comparing these version values is an easy way to implement checks before updating (cited from StackOverflow).
Downloading Updates
To download an update package to the device, we can use the Android DownloadManager. The DownloadManager provides APIs to request downloads, query completed downloads, and access metadata about downloads in progress.
To initialize the DownloadManager, we need to get an instance via the getSystemService() method:
DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
Next, we can set up a download request by creating a DownloadManager.Request object. This allows us to specify properties like the download URL, title, description, destination path, etc. For example:
DownloadManager.Request request = new DownloadManager.Request(updateUrl);
request.setTitle("App Update");
request.setDescription("Downloading latest app update");
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "update.apk");
Finally, we can enqueue the request using the downloadManager instance. This will return a long ID we can use later to query status:
long downloadId = downloadManager.enqueue(request);
The DownloadManager will now download the file in the background. We can query the status or retrieve the local file path once it completes.
Installing Updates
A key part of updating an Android app programmatically is installing the update silently, without requiring any user interaction. This allows the app to update seamlessly in the background. To enable silent updates, the app needs to request the INSTALL_PACKAGES permission.
Silent installs are often used in enterprise device management scenarios, where administrators need to push app updates to employee devices remotely. Platforms like VMware Workspace ONE UEM allow admins to configure apps for silent install during deployment.
To implement silent install capabilities in an Android app, the app should first check whether the INSTALL_PACKAGES permission is granted. If not, the permission can be requested at runtime. With the permission granted, the app can then initiate a silent install using the PackageManager API. Specifically, the installPackage() method allows passing the ALLOW_TEST flag to install quietly.
After starting the silent install, the app should monitor the package status to detect when the update is complete. The setUpdateAvailableListener() method of the PackageManager can be used to get callbacks on status changes. Once the update is finished installing, the app may need to restart itself or notify the user that a new version is available. Thorough testing is important to ensure seamless silent updating.
Testing
Thoroughly testing the end-to-end workflow of updating your Android app programmatically is crucial before releasing to production. You’ll want to test the full process on both emulators and real devices to catch any issues early. Some best practices for testing include:
Test with different version numbers to ensure the update process works smoothly whether it’s a minor or major update. As noted in the Android developer documentation, you’ll need to use separate user accounts that own your app in order to fully test in-app updates.
Leverage different types of testing like unit tests, integration tests, and UI tests at each stage. For example, add tests to validate the version check logic, the update task workflow, and the actual update installation and UI update.
Try testing on different API levels to check backwards compatibility. Test on both WiFi and cellular networks to cover different connectivity scenarios. Purposefully trigger errors to validate your exception handling. Enabling fake app install on emulators as outlined in this Stack Overflow post can also help simplify update testing.
Setting up robust testing for your update workflow will help catch bugs early and ensure a smooth experience for your users when releasing app updates.
