Android location provider mock

So, yeah, I resumed playing around with android, this time version 2.0.

I’m really tempted to buy the new Motorola Milestone that should come out in Europe sometime between… now… and early next year, so I wanna be ready to create all the crazy stuff I have in mind for it

One of the things I noticed was that it’s not that straightforward to provide sample GPS data. Somehow the emulator’s GPX and KMZ functionality is not working fine for me and, even if it was, I don’t want to load the file everytime (i.e. I’m lazy).

So, after some googling around, here’s my solution to read points from a file and feed them 1 per second to the location manager, so I can finally work with them in my app:

My main activity implements LocationListener, so it can be passed to the LocationManager to receive GPS events. Here’s what I do when creating my activity:

public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		((TextView) this.findViewById(R.id.textView)).setText("Something else");

		// LocationManager locationManager = (LocationManager)
		// getSystemService(Context.LOCATION_SERVICE);
		// locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
		// 0, 0, this);

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

		String mocLocationProvider = LocationManager.GPS_PROVIDER;
		locationManager.addTestProvider(mocLocationProvider, false, false,
				false, false, true, true, true, 0, 5);
		locationManager.setTestProviderEnabled(mocLocationProvider, true);
		locationManager.requestLocationUpdates(mocLocationProvider, 0, 0, this);

		try {

			List data = new ArrayList();
			InputStream is = getAssets().open("data.txt");
			BufferedReader reader = new BufferedReader(new InputStreamReader(is));
			String line = null;
			while ((line = reader.readLine()) != null) {

				data.add(line);
			}
			Log.e(LOG_TAG, data.size() + " lines");

			new MockLocationProvider(locationManager, mocLocationProvider, data).start();

		} catch (IOException e) {

			e.printStackTrace();
		}
	}

This will basically setup the test location provider and read the points into a list. Then I feed that stuff to my mock location provider (just a normal thread) that will read them 1 per second and trigger the new location back to this activity. Here’s the code for MockLocationProvider:

public class MockLocationProvider extends Thread {

    private List data;

    private LocationManager locationManager;

    private String mocLocationProvider;

    private String LOG_TAG = "faren";

    public MockLocationProvider(LocationManager locationManager,
            String mocLocationProvider, List data) throws IOException {

        this.locationManager = locationManager;
        this.mocLocationProvider = mocLocationProvider;
        this.data = data;
    }

    @Override
    public void run() {

        for (String str : data) {

            try {

                Thread.sleep(1000);

            } catch (InterruptedException e) {

                e.printStackTrace();
            }

            // Set one position
            String[] parts = str.split(",");
            Double latitude = Double.valueOf(parts[0]);
            Double longitude = Double.valueOf(parts[1]);
            Double altitude = Double.valueOf(parts[2]);
            Location location = new Location(mocLocationProvider);
            location.setLatitude(latitude);
            location.setLongitude(longitude);
            location.setAltitude(altitude);

            Log.e(LOG_TAG, location.toString());

            // set the time in the location. If the time on this location
            // matches the time on the one in the previous set call, it will be
            // ignored
            location.setTime(System.currentTimeMillis());

            locationManager.setTestProviderLocation(mocLocationProvider,
                    location);
        }
    }
}

Notice the location.setTime() call. Read the comment why it is necessary. Took me forever to find this one in google

Peace and great Androiding

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