microg/GmsCore · error · NullPointerException

transitionEvents list can't be null.

Error message

transitionEvents list can't be null.

What it means

The ActivityTransitionResult(List<ActivityTransitionEvent>) constructor validates its input: a null transitionEvents list fails the Preconditions check and raises NullPointerException with this message.

Source

Thrown at play-services-location/src/main/java/com/google/android/gms/location/ActivityTransitionResult.java:42

@PublicApi
public class ActivityTransitionResult extends AutoSafeParcelable {
    private static final String EXTRA = "com.google.android.location.internal.EXTRA_ACTIVITY_TRANSITION_RESULT";

    @Field(value = 1, subClass = ActivityTransitionEvent.class)
    @NonNull
    private List<ActivityTransitionEvent> transitionEvents;
    @Field(2)
    private Bundle extras;

    /**
     * Constructs a result by specifying a list of transition events.
     *
     * @param transitionEvents the transition events
     * @throws NullPointerException     if {@code transitionEvents} is {@code null}
     * @throws IllegalArgumentException if the events in {@code transitionEvents} are not in ascending order of time
     */
    public ActivityTransitionResult(List<ActivityTransitionEvent> transitionEvents) {
        if (transitionEvents == null) throw new NullPointerException("transitionEvents list can't be null.");
        for (int i = 1; i < transitionEvents.size(); i++) {
            if (transitionEvents.get(i).getElapsedRealTimeNanos() < transitionEvents.get(i - 1).getElapsedRealTimeNanos())
                throw new IllegalArgumentException();
        }
        this.transitionEvents = Collections.unmodifiableList(transitionEvents);
    }

    /**
     * Gets all the activity transition events in this result. The events are in ascending order of time, and may include events in the past.
     */
    public List<ActivityTransitionEvent> getTransitionEvents() {
        return transitionEvents;
    }

    /**
     * Extracts the {@link ActivityTransitionResult} from the given {@link Intent}.
     *
     * @param intent the {@link Intent} to extract the result from

View on GitHub (pinned to 157c9d86ac)

Solutions

1. Pass a non-null (possibly empty) list of ActivityTransitionEvent
2. Default to Collections.emptyList() when reconstructing from missing data

When it happens

Trigger: Thrown at play-services-location/src/main/java/com/google/android/gms/location/ActivityTransitionResult.java:42 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microg/GmsCore@157c9d86ac (2026-09-06). Data as JSON: /api/errors/c2eccf8af1b0ed7a. Report an issue: GitHub.