当有人走进地理围栏时如何显示 Toast 消息？

Question

所以我设置了这个地理围栏。当有人进入或退出地理围栏时，我可以显示通知，但我似乎无法发送消息。我认为您会将 Toast 消息放在 onHandleIntent() 方法中，但这似乎不起作用。希望大家多多指教。

这是我的课。

public class GeofenceTransitionsIntentService extends IntentService {
    protected static final String TAG = "geofence-transitions-service";

    public GeofenceTransitionsIntentService() {
        // Use the TAG to name the worker thread.
        super(TAG);
    }

    @Override
    public void onCreate()
    {
        super.onCreate();
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        GeofencingEvent geofencingEvent = GeofencingEvent.fromIntent(intent);
        if (geofencingEvent.hasError()) {
            String errorMessage = GeofenceErrorMessages.getErrorString(this,
                    geofencingEvent.getErrorCode());
            Log.e(TAG, errorMessage);
            return;
        }

        // Get the transition type.
        int geofenceTransition = geofencingEvent.getGeofenceTransition();

        // Test that the reported transition was of interest.
        if (geofenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER ||
                geofenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT) {

            // Get the geofences that were triggered. A single event can trigger multiple geofences.
            List<Geofence> triggeringGeofences = geofencingEvent.getTriggeringGeofences();

            // Get the transition details as a String.
            String geofenceTransitionDetails = getGeofenceTransitionDetails(
                    this,
                    geofenceTransition,
                    triggeringGeofences
            );

            // Send notification and log the transition details.
            sendNotification(geofenceTransitionDetails);
            Toast.makeText(getBaseContext(),"Entered my geoFence :D",Toast.LENGTH_SHORT).show();
            Log.i(TAG, geofenceTransitionDetails);
        } else {
            // Log the error.
            Log.e(TAG, getString(R.string.geofence_transition_invalid_type, geofenceTransition));
        }
    }

    private String getGeofenceTransitionDetails(
            Context context,
            int geofenceTransition,
            List<Geofence> triggeringGeofences) {

        String geofenceTransitionString = getTransitionString(geofenceTransition);

        // Get the Ids of each geofence that was triggered.
        ArrayList triggeringGeofencesIdsList = new ArrayList();
        for (Geofence geofence : triggeringGeofences) {
            triggeringGeofencesIdsList.add(geofence.getRequestId());
        }
        String triggeringGeofencesIdsString = TextUtils.join(", ", triggeringGeofencesIdsList);

        return geofenceTransitionString + ": " + triggeringGeofencesIdsString;
    }

    private String getTransitionString(int transitionType) {
        switch (transitionType) {
            case Geofence.GEOFENCE_TRANSITION_ENTER:
                return getString(R.string.geofence_transition_entered);
            case Geofence.GEOFENCE_TRANSITION_EXIT:
                return getString(R.string.geofence_transition_exited);
            default:
                return getString(R.string.unknown_geofence_transition);
        }
    }

    private void sendNotification(String notificationDetails) {
        // Create an explicit content Intent that starts the main Activity.
        Intent notificationIntent = new Intent(getApplicationContext(), Main.class);

        // Construct a task stack.
        TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);

        // Add the main Activity to the task stack as the parent.
        stackBuilder.addParentStack(Main.class);

        // Push the content Intent onto the stack.
        stackBuilder.addNextIntent(notificationIntent);

        // Get a PendingIntent containing the entire back stack.
        PendingIntent notificationPendingIntent =
                stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

        // Get a notification builder that's compatible with platform versions >= 4
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this);

        // Define the notification settings.
        builder.setSmallIcon(R.drawable.ic_launcher)
                // In a real app, you may want to use a library like Volley
                // to decode the Bitmap.
                .setLargeIcon(BitmapFactory.decodeResource(getResources(),
                        R.drawable.ic_launcher))
                .setColor(Color.RED)
                .setContentTitle(notificationDetails)
                .setContentText(getString(R.string.geofence_transition_notification_text))
                .setContentIntent(notificationPendingIntent);

        // Dismiss notification once the user touches it.
        builder.setAutoCancel(true);

        // Get an instance of the Notification manager
        NotificationManager mNotificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        // Issue the notification
        mNotificationManager.notify(0, builder.build());
    }

}

目前，我将 toast 放在 onHandleIntent() 方法底部的 if 语句中。我的完整源代码直接来自谷歌的地理围栏教程：http://io2015codelabs.appspot.com/codelabs/geofences#1

Answer 1

这是一个IntentService，因此对onHandleIntent 的回调在后台线程中执行。

您需要在主 UI 线程上执行 Toast 才能在屏幕上正确显示它。

看看这个答案，看看如何从服务访问主线程

Accessing UI thread handler from a service

Answer 2

试试这个：

@Override
protected void onHandleIntent(Intent intent) {

    GeofencingEvent geofencingEvent = GeofencingEvent.fromIntent(intent);
    if (geofencingEvent.hasError()) {
        String errorMessage = GeofenceErrorMessages.getErrorString(this,
                geofencingEvent.getErrorCode());
        Log.e(TAG, errorMessage);
        return;
    }

    int geofenceTransition = geofencingEvent.getGeofenceTransition();


    if (geofenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER ||
            geofenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT) {

        // Get the geofences that were triggered. A single event can trigger multiple geofences.
        List<Geofence> triggeringGeofences = geofencingEvent.getTriggeringGeofences();


        String geofenceTransitionDetails = getGeofenceTransitionDetails(
                this,
                geofenceTransition,
                triggeringGeofences
        );

        // Showing toast for location transition
        Handler handler = new Handler(Looper.getMainLooper());
        handler.post(new Runnable() {

            @Override
            public void run() {
                Toast.makeText(context,geofenceTransitionDetails,Toast.LENGTH_SHORT).show();
            }
        });


        Log.i(TAG, geofenceTransitionDetails);
    } else {
        // Log the error.
        Log.e(TAG, getString(R.string.geofence_transition_invalid_type, geofenceTransition));
    }
}