Problem med parseing i Android och JSON. String->double

public class LagerActivity extends Activity {

	private static String url = "http://agent.nocrew.org/api/json/1.0/searchStore.json?limit=5...";

	static final String TAG_ITEMS = "items";
	static final String TAG_LAT = "lat";
	static final String TAG_LNG = "lng";

	private GoogleMap mMap;
	private LocationManager locationManager;

	JSONArray items = null;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_lager);
		mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
				.getMap();

		// Creating JSON Parser instance
		JSONparser jParser = new JSONparser();
		// getting JSON string from URL
		JSONObject json = jParser.getJSONFromUrl(url);

		try {
			// Getting Array of Contacts
			items = json.getJSONArray(TAG_ITEMS);
			// looping through All Contacts
			for (int i = 0; i < items.length(); i++) {
				JSONObject c = items.getJSONObject(i);

				// Storing each json item in variable
				String lat = c.getString(TAG_LAT);
				String lng = c.getString(TAG_LNG);

				// lat = lat.replace(",", ".");
				// lng = lng.replace(",", ".");

				// Log.e(lat, lng);

				double lati = Double.parseDouble(lat);

				Log.d(Double.toString(lati), " ");

				// LatLng point = new LatLng(Double.parseDouble(lat),
				// Double.parseDouble(lng));
			        // mMap.addMarker(new MarkerOptions().position(point)
				// .title("Karls räkor & hund")
				// .snippet("blaha, ehehe"));
			
			}

		} catch (JSONException e) {
			e.printStackTrace();
		}

	}

}

01-11 18:10:23.294: W/dalvikvm(22718): threadid=1: thread exiting with uncaught exception (group=0x40e86930)
01-11 18:10:23.294: E/AndroidRuntime(22718): FATAL EXCEPTION: main
01-11 18:10:23.294: E/AndroidRuntime(22718): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.checkmypint/com.example.checkmypint.LagerActivity}: java.lang.NumberFormatException: Invalid double: ""
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.os.Handler.dispatchMessage(Handler.java:99)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.os.Looper.loop(Looper.java:137)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread.main(ActivityThread.java:5039)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at java.lang.reflect.Method.invokeNative(Native Method)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at java.lang.reflect.Method.invoke(Method.java:511)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at dalvik.system.NativeStart.main(Native Method)
01-11 18:10:23.294: E/AndroidRuntime(22718): Caused by: java.lang.NumberFormatException: Invalid double: ""
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at java.lang.StringToReal.invalidReal(StringToReal.java:63)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at java.lang.StringToReal.parseDouble(StringToReal.java:248)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at java.lang.Double.parseDouble(Double.java:295)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at com.example.checkmypint.LagerActivity.onCreate(LagerActivity.java:65)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.Activity.performCreate(Activity.java:5104)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-11 18:10:23.294: E/AndroidRuntime(22718): 	... 11 more

// lat = lat.replace(",", ".");
// lng = lng.replace(",", ".");

if (lat == null || lat.length() == 0) {
lat = "0";
	} else {
	lati = Double.parseDouble(lat);
	}

	if (lng == null || lng.length() == 0) {
	lng = "0";
		} else {
	           lngi = Double.parseDouble(lng);
	}