Скачать или смотреть Resolving the onStart() Issue with PendingIntents in Android Notifications

Discover how to manage the `onStart()` method in Android's Launcher Activity when using PendingIntent for notifications, especially in Android 11 and below.
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Understanding the onStart() Challenge with PendingIntents in Android Notifications

In Android app development, managing how your app responds to notifications is critical for a smooth user experience. A common scenario arises when an app is clicked while it is in the background. You might find that your defined flow for handling notifications does not work as expected—specifically, the onStart() method of your Launcher Activity being triggered before your intended activity. Let's break down this issue, particularly for Android 11 and below, and see how you can resolve it.

The Problem

When trying to show notifications in your app upon receiving a Firebase Cloud Messaging (FCM) message, you might want to transition through an intermediary activity (in this case, PushTracker) for processing before navigating to your destination activity.

Here’s the critical part of the problem:

Foreground and Killed State: When the app is either in the foreground or killed, the PushTracker activity is called first as intended.

Background State: When the app is in the background (e.g., when the user presses the home button), clicking the notification leads to your Main Activity's onStart() being called first, before the intended PushTracker activity. This unexpected behavior primarily occurs on Android 11 and below.

Key Observations

This is a known issue with the interaction of the PendingIntent and the activity launch flows in these Android versions.

The onStart() of the launcher activity gets triggered, which can mess with the state management of your app and its lifecycle.

Exploring the Root Cause

The behavior you're observing derives from how Android handles activity launches based on certain conditions. Specifically:

Launcher Activity Invocation: In standard and other launch modes, when notification is clicked, the PendingIntent routes through the launcher activity. This explains why onStart() is called first.

Using Data Payload: Since you are utilizing data payload in FCM rather than the notification payload, this affects the routing of intent, leading to this behavior.

A Potential Solution

After grappling with this issue, a workaround has been identified that effectively circumvents the problem: modifying the launch mode of the PushTracker activity to singleInstance in the AndroidManifest. Here’s how to implement that:

Step to Implement the Solution

Modify the Manifest for PushTracker:

[[See Video to Reveal this Text or Code Snippet]]

What This Changes

By setting the PushTracker activity to singleInstance, it operates independently and does not route through the launcher activity. Thus, the behavior you expect—where PushTracker is called first—is maintained.

Conclusion

Managing notifications and activity transitions in Android can sometimes lead to challenges, especially given the various Android versions. The trick with the singleInstance launch mode for your PushTracker activity is a robust solution to ensure your app behaves as intended without falling into the trap of unnecessary launcher activity calls.

In summary:

Remember to test your application across different Android versions to identify these issues early.

Adjust your activity configurations thoughtfully, especially with regard to launchMode, to tailor the behavior to your needs.

With this knowledge, you're better equipped to handle notifications and their consequences on your application lifecycle efficiently!