Question

Background

I am writing an Android app whose main function is tracking the user’s location and making an alert when the user gets near some point. Therefore I need to update the user’s location at regular intervals, and these intervals should get smaller as the user comes closer to the target. So when the user is within, say, 1 km of the target, I want the location to be updated every 20 seconds and so on, until the user arrives.

Problem

When I test it (provider = LocationManager.NETWORK_PROVIDER), a call to requestLocationUpdates(provider, minTime, minDistance, locationListener) with any minTime < 45000 has the same effect as minTime = 45000, i.e. I get updates with an interval of exactly 45 seconds.
I know the minimum time parameter is only a “hint”, but it is not taken as a hint by my app. I get updates with the interval specified until that interval passes below 45 seconds. It seems as though a minimum time of 45 seconds between location updates is hardcoded into Android, but that would be kind of odd. Plus I have never heard of this problem before, and I have not been able to find it addressed here on Stackoverflow.

Because I am not able to get frequent updates, my workaround (for now) is to manually call requestLocationUpdates whenever a new location is needed, and then just use the first available location. To do this at small intervals I use handler.postDelayed(myRunnable, updateInterval) to delay the calls, and myRunnable then takes care of calling requestLocationUpdates. However, this method only works about 50 (apparently random) percent of the time.

Does anybody know of the problem, and is there a way to fix it? Or is my only option to set minTime = 0 and just hope for the best?

Source code

Here is the source code for myRunnable, whose run() method I manually call regularly with handler.postDelayed(myRunnable, updateInterval):

public class MyRunnable implements Runnable {
    private LocationManager manager;
    private LocationListener listener;

    @Override
    public void run() {
        // This is called everytime a new update is requested
        // so that only one request is running at a time.
        removeUpdates();

        manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        listener = new LocationListener() {
            @Override
            public void onLocationChanged(Location loc) {
                location = loc;
                latitude = loc.getLatitude();
                longitude = loc.getLongitude();
                accuracy = Math.round(loc.getAccuracy());

                handler.sendMessage(Message.obtain(handler, KEY_MESSAGE_LOCATION_CHANGED));

                checkForArrival();
            }

            // Other overrides are empty.
        };

        if(!arrived)
            manager.requestLocationUpdates(provider, updateInterval, 0, listener);
    }

    /**
     * Removes location updates from the LocationListener.
     */
    public void removeUpdates() {
        if(!(manager == null || listener == null))
            manager.removeUpdates(listener);
    }

    // Another method for "cleaning up" when the user has arrived.
}

And here is my handler:

handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch(msg.what) {
            case KEY_MESSAGE_LOCATION_CHANGED:
                if(myRunnable != null) {
                    myRunnable.removeUpdates();
                    handler.postDelayed(myRunnable, updateInterval);
                }
                break;
            }
        }
    };

Additional info

The whole location updating thing runs in a service.

I have read the doc several times, Google’d the problem, and tried various other workarounds. Nothing quite does it.

I have logged the damn out of this thing, and the only exciting thing to see is a big fat “ignore” to my frequent location requests. All the right methods are called.

Any help will be very much appreciated!

Answer 1

You can set the minTime to any value. However, you will only get an update once a new location is available. The network only updates every 45 sec or so on every phone I own. This seems to be a limitation of the Network Provider. If you want more frequent updates use the GPS provider. Depending on the GPS hardware you should get a maximum update rate around 4Hz.