Activity-Alias gets removed on app update

Activity Alias Removal on App Update

This article explores the issue of activity aliases getting removed when an Android application is updated.

Understanding Activity Aliases

An activity alias is a secondary entry point to an activity within your Android app. It allows you to provide different ways to launch an activity, potentially using different intents or labels. Aliases are particularly useful for:

• Deep linking
• Providing custom launchers for different scenarios
• Supporting multiple entry points for the same activity

The Issue: Aliases Disappearing After Update

A common problem is that activity aliases can be removed when an app is updated. This is because the Android system manages app updates by:

• Installing the new APK (Application Package File) to a different location.
• Updating the existing app data to the new version.
• Replacing the old APK with the new one.

This process, while efficient, often leads to the loss of activity aliases. The new APK might have a different structure or configuration, leading to the removal of aliases from the previous version.

Why This Happens

Manifest Changes

The most common reason for alias loss is modifications to the Android Manifest file. Changes to the <activity> elements or the removal of the <alias> tag itself can result in the alias disappearing.

Version Code Changes

When the app’s version code is increased during an update, the Android system may treat it as a completely new installation. This could lead to the removal of previous configurations, including aliases.

Solutions and Workarounds

1. Preserve Alias Declarations

The most reliable way to ensure aliases persist is to explicitly declare them in the updated app’s Android Manifest. This means making sure they are present and correctly configured in the new APK.

2. Migrate Aliases During Update

If you need to update the alias configuration, implement a migration mechanism during the app update process. This might involve:

• Reading the old alias configuration from the previous APK.
• Updating the configuration in the new APK’s Manifest.
• Applying any necessary changes to the alias definition.

3. Use App Linking

For deep linking scenarios, consider using App Linking. App Linking allows you to define links that can open specific activities within your app, even if the user doesn’t have the latest version installed.

Example Manifest Configuration (Before Update)

<manifest ...>
    <application ...>
        <activity android:name=".MainActivity" ...>
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            <intent-filter>
        </activity>
        
        <activity android:name=".SettingsActivity" ...>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:scheme="myapp" android:host="settings" />
            <intent-filter>
        </activity>
        
        <activity-alias android:name=".SettingsAlias"
            android:targetActivity=".SettingsActivity" />
    </application>
</manifest>

Example Manifest Configuration (After Update)

<manifest ...>
    <application ...>
        <activity android:name=".MainActivity" ...>
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            <intent-filter>
        </activity>
        
        <activity android:name=".SettingsActivity" ...>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:scheme="myapp" android:host="settings" />
            <intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:scheme="myapp" android:host="config" />
            <intent-filter>
        </activity>
        
        <activity-alias android:name=".SettingsAlias"
            android:targetActivity=".SettingsActivity" />
    </application>
</manifest>

Conclusion

Managing activity aliases across app updates can be a complex task. Understanding the reasons why aliases are removed and applying the recommended solutions will help you maintain seamless functionality and deep linking for your Android application.