Android 16 Developer Preview 2: jobs and traces

Developer Preview 2 came out on 18 December 2024. Google said its changes were “designed to enhance the app experience, improve battery life, and boost performance while minimizing incompatibilities”. Phones on DP1 got it over the air; it was still a developer-only build.

What Developer Preview 2 added

• System-triggered profiling. ProfilingManager.addProfilingTriggers() asks the system to capture a trace on a cold start (onFullyDrawn) or an ANR, cases an app cannot trace itself.
• Start component. ApplicationStartInfo.getStartComponent() says which kind of component started the process.
• Job introspection. JobScheduler.getPendingJobReasons(int) returns every reason a job is waiting, and getPendingJobReasonsHistory(int) the recent constraint changes.
• Adaptive refresh rate. hasArrSupport() and getSuggestedFrameRate(int) arrived, and getSupportedRefreshRates() was restored.
• Richer haptics. Apps can define the amplitude and frequency curves of a haptic effect, independent of the device’s actuator.
• Predictive back. PRIORITY_SYSTEM_NAVIGATION_OBSERVER lets an app see system-handled back gestures, and finishAndRemoveTaskCallback() and moveTaskToBackCallback() trigger system animations.
• Other. Cloud search APIs for the photo picker; secure Wi-Fi ranging with 802.11az, with AES-256 encryption and protection against man-in-the-middle attacks; and an ACTIVITY_INTENSITY data type in Health Connect.

What Developer Preview 2 changed

• Job quotas. Regular and expedited job runtime now depends on the standby bucket, and also counts while the app is visible or running a foreground service.
• setImportantWhileForeground(). Deprecated since Android 12, it is now ignored, and isImportantWhileForeground() returns false.
• Accessibility announcements. announceForAccessibility() and TYPE_ANNOUNCEMENT events are deprecated in favour of pane titles, live regions and setError().

The build also fixed a Terminal app error, “No local assets”, reported on DP1.