处理多个地理围栏过渡与公共区域

Question

如果我有这两个地理围栏，在注册这些地理围栏后，当我进入或退出这些圈子的圆周时，我会得到通知。但是，如果我在公共区域移动，即从一圈到另一圈，我不希望我的应用程序发送通知。

有可能吗？如果是这样，那怎么样？

Answer 1

您必须使用class来监控击剑：

public class GeofenceReceiver extends BroadcastReceiver {
    Context context;

    Intent broadcastIntent = new Intent();

    @Override
    public void onReceive(Context context, Intent intent) {
        this.context = context;

        broadcastIntent.addCategory(GeofenceUtils.CATEGORY_LOCATION_SERVICES);

        if (LocationClient.hasError(intent)) {
            handleError(intent);
        } else {
            handleEnterExit(intent);
        }
    }

    private void handleError(Intent intent){
        // Get the error code
        int errorCode = LocationClient.getErrorCode(intent);

        // Get the error message
        String errorMessage = LocationServiceErrorMessages.getErrorString(
                context, errorCode);

        // Log the error
        Log.e(GeofenceUtils.APPTAG,
                context.getString(R.string.geofence_transition_error_detail,
                        errorMessage));

        // Set the action and error message for the broadcast intent
        broadcastIntent
                .setAction(GeofenceUtils.ACTION_GEOFENCE_ERROR)
                .putExtra(GeofenceUtils.EXTRA_GEOFENCE_STATUS, errorMessage);

        // Broadcast the error *locally* to other components in this app
        LocalBroadcastManager.getInstance(context).sendBroadcast(
                broadcastIntent);
    }


    private void handleEnterExit(Intent intent) {
        // Get the type of transition (entry or exit)
        int transition = LocationClient.getGeofenceTransition(intent);

        // Test that a valid transition was reported
        if ((transition == Geofence.GEOFENCE_TRANSITION_ENTER)
                || (transition == Geofence.GEOFENCE_TRANSITION_EXIT)) {

            // Post a notification
            List<Geofence> geofences = LocationClient
                    .getTriggeringGeofences(intent);
            String[] geofenceIds = new String[geofences.size()];
            String ids = TextUtils.join(GeofenceUtils.GEOFENCE_ID_DELIMITER,
                    geofenceIds);
            String transitionType = GeofenceUtils
                    .getTransitionString(transition);

            for (int index = 0; index < geofences.size(); index++) {
                Geofence geofence = geofences.get(index);
                ...do something with the geofence entry or exit. I'm saving them to a local sqlite db

            }
            // Create an Intent to broadcast to the app
            broadcastIntent
                    .setAction(GeofenceUtils.ACTION_GEOFENCE_TRANSITION)
                    .addCategory(GeofenceUtils.CATEGORY_LOCATION_SERVICES)
                    .putExtra(GeofenceUtils.EXTRA_GEOFENCE_ID, geofenceIds)
                    .putExtra(GeofenceUtils.EXTRA_GEOFENCE_TRANSITION_TYPE,
                            transitionType);

            LocalBroadcastManager.getInstance(MyApplication.getContext())
                    .sendBroadcast(broadcastIntent);

            // Log the transition type and a message
            Log.d(GeofenceUtils.APPTAG, transitionType + ": " + ids);
            Log.d(GeofenceUtils.APPTAG,
                    context.getString(R.string.geofence_transition_notification_text));

            // In debug mode, log the result
            Log.d(GeofenceUtils.APPTAG, "transition");

            // An invalid transition was reported
        } else {
            // Always log as an error
            Log.e(GeofenceUtils.APPTAG,
                    context.getString(R.string.geofence_transition_invalid_type,
                            transition));
        }
    }

    //Posts a notification in the notification bar when a transition 
    private void sendNotification(String transitionType, String locationName) {

        // Create an explicit content Intent that starts the main Activity
        Intent notificationIntent = new Intent(context, MainActivity.class);

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

        // Adds the main Activity to the task stack as the parent
        stackBuilder.addParentStack(MainActivity.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(
                context);

        // Set the notification contents
        builder.setSmallIcon(R.drawable.ic_notification)
                .setContentTitle(transitionType + ": " + locationName)
                .setContentText(
                        context.getString(R.string.geofence_transition_notification_text))
                .setContentIntent(notificationPendingIntent);

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

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

您应该为要监视的每个区域创建侦听器，比如说listener1和listener2。为了优化这两个区域并对其进行集成，最好的方法是使用MongoDB创建一个网格，在这种情况下甚至允许您在构建网格时集成两个以上的点。

假设您要以某些Lat-Lon点的形式出现多边形，那么您可以生成grid，如下所示：

# Method to get the min and max values for the polygon  
def get_bounding_box(coords)
# get max and min coords
max = coords.inject({lat:0, lon:0}) do |max, c|
max[:lon] = c[0] if c[0] > max[:lon]
max[:lat] = c[1] if c[1] > max[:lat]
max
end
min = coords.inject({lat:MAX_LAT, lon:MAX_LON}) do |min, c|
min[:lon] = c[0] if c[0] < min[:lon]
min[:lat] = c[1] if c[1] < min[:lat]
min
end
# add a little padding to the max and min
max.each {|k, v| max[k] += 1 }
min.each {|k, v| min[k] -= 1 }

{min: min, max: max}
end

def generate_grid(bounds)
lon_range = bounds[:min][:lon]...bounds[:max][:lon]
lat_range = bounds[:min][:lat]...bounds[:max][:lat]

grid = []
lon_range.each do |lon|
lat_range.each do |lat|
grid << [lon + 0.25, lat + 0.25]
grid << [lon + 0.25, lat + 0.75]
grid << [lon + 0.75, lat + 0.25]
grid << [lon + 0.75, lat + 0.75]
end
end

grid
end

此类方法允许您使用智能电网实现very efficient地理围栏以监控目标区域：

最近MongoDB还添加了对Android的支持，从而为您的Android App后端集成提供了一种简便的方法。事实上，智能分布式数据的地理围栏开发预计会有越来越多的applications。

Answer 2

这可能是另一种选择：

所有地理围栏都有id;我不确定它们是否必须是唯一的，但是对于这个讨论，我们说它们必须是独一无二的。在你的两个地理围栏例子中，让我们使用id“fenceHome-1”和“fenceHome-2”作为显示的，以及第三个名为“someOther-1”的未示出。

现在你可以做的是创建一个变量来存储用户所在的当前地理围栏。在这个例子中，它将是一个带有地理围栏id的String。我们称之为

String currentGeofence = new String();

当用户输入新的地理围栏时，您现在可以检查geofenceId是否相同。

     /** 
        geofenceEntered  get from the Intent.  Should be "fenceHome-1" or "fenceHome-2" or "someOther=1" 
        */    
    public void enteredGeoFence(String geofenceEntered) {

        // strip off the "-1" or "-2"  
        geofenceEntered = geofenceEntered.stripOff(); 

        if (currentGoofence.equals(geofenceEntered) == false} {
           // user entered a new geofence  Ex: "SomeOther-1" to "fenceHome-1" 
           sendNotification(geofenceEntered, .....); 
           currentGeofence = geofencecEntered;
        } else {
           // user entered a geofence with in the same 'area'.  Ex:  "fenceHome-1" to "fenceHome-2" 
           // do nothing 
        }

    }

我就是这样做的。摆弄所有数学太难了。只需为地理围栏ID设置一个聪明的命名约定。 关键是地理围栏的命名。

在现实世界中，currentGeofence需要是一个Collection，因为用户可能在多个地理围栏中，geofenceExit（）必须从currentGeofence中删除。

要记住Android Notification Manager的另一件事是：如果您发送两次相同的通知，它只会发送一个通知。这可能会对您有利。

Answer 3

非常示意性地：

boolean isTransition1, isTransition2, isTransition, insideCircle1, insideCircle2, insideUnion, insideUnionPrev;

if (isTransition1 | isTransition2) {
    insideCircle1 = (dist(currPosition, centerCircle1) < radius1);
    insideCircle2 = (dist(currPosition, centerCircle2) < radius2);
    insideUnionPrev = insideUnion;
    insideUnion = insideCircle1 | insideCircle;
    isTransition = (insideUnion != insideUnionPrev);
    if (isTransition & insideUnion) println("Moved into region");
    if (isTransition & !insideUnion) println("Moved out of region");
}