How to work with Android’s in-app update API?

Step 1: Add dependency (build.gradle (app)):

dependencies {

    implementation 'com.google.android.play:core:1.7.3'
    ...
}

Step 2: Check for update availability and start if it’s available

private AppUpdateManager mAppUpdateManager;
private static final int RC_APP_UPDATE = 11;

In onStart() method:

mAppUpdateManager = AppUpdateManagerFactory.create(this);

mAppUpdateManager.registerListener(installStateUpdatedListener);

mAppUpdateManager.getAppUpdateInfo().addOnSuccessListener(appUpdateInfo -> {

        if (appUpdateInfo.updateAvailability() == UpdateAvailability.UPDATE_AVAILABLE
                && appUpdateInfo.isUpdateTypeAllowed(AppUpdateType.FLEXIBLE /*AppUpdateType.IMMEDIATE*/)){

            try {    
                    mAppUpdateManager.startUpdateFlowForResult(
                            appUpdateInfo, AppUpdateType.FLEXIBLE /*AppUpdateType.IMMEDIATE*/, MainActivity.this, RC_APP_UPDATE);

            } catch (IntentSender.SendIntentException e) {
                e.printStackTrace();
            }

        } else if (appUpdateInfo.installStatus() == InstallStatus.DOWNLOADED){
            //CHECK THIS if AppUpdateType.FLEXIBLE, otherwise you can skip
            popupSnackbarForCompleteUpdate();
        } else {
            Log.e(TAG, "checkForAppUpdateAvailability: something else");
        }
    });

Step 3: Listen to update state

InstallStateUpdatedListener installStateUpdatedListener = new 
  InstallStateUpdatedListener() {
    @Override
    public void onStateUpdate(InstallState state) {
        if (state.installStatus() == InstallStatus.DOWNLOADED){
            //CHECK THIS if AppUpdateType.FLEXIBLE, otherwise you can skip
            popupSnackbarForCompleteUpdate();
        } else if (state.installStatus() == InstallStatus.INSTALLED){
            if (mAppUpdateManager != null){
          mAppUpdateManager.unregisterListener(installStateUpdatedListener);
            }

        } else {
            Log.i(TAG, "InstallStateUpdatedListener: state: " + state.installStatus());
        }
    }
};

Step 4: Get a callback for update status

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == RC_APP_UPDATE) {
        if (resultCode != RESULT_OK) {
            Log.e(TAG, "onActivityResult: app download failed");
        }
    }
}

Step 5: Flexible update

private void popupSnackbarForCompleteUpdate() {

    Snackbar snackbar =
            Snackbar.make(
                    findViewById(R.id.coordinatorLayout_main),
                    "New app is ready!",
                    Snackbar.LENGTH_INDEFINITE);

    snackbar.setAction("Install", view -> {
        if (mAppUpdateManager != null){
            mAppUpdateManager.completeUpdate();
        }
    });

    
snackbar.setActionTextColor(getResources().getColor(R.color.install_color));
    snackbar.show();
}

Step 6: Don’t forget to unregister listener (in onStop method)

if (mAppUpdateManager != null) {
     mAppUpdateManager.unregisterListener(installStateUpdatedListener);
}

Note: Add this listener in any one activity in your app preferably in MainActivity (Home page)

For testing, you can use FakeAppUpdateManager

https://developer.android.com/reference/com/google/android/play/core/appupdate/testing/FakeAppUpdateManager.html

Constraint: In-app update works only with devices running Android 5.0 (API level 21) or higher

Official Documentation: https://developer.android.com/guide/playcore/in-app-updates