リストビューに表示される距離計算を実行する簡単なプログラムを作成しようとしています。Androidhive の GPSTracker を使用し、リスト アクティビティの緯度と経度を呼び出します
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
boolean isGPSEnabled =false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context){
this.mContext = context;
getLocation();
}
public Location getLocation() {
try{
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if(!isGPSEnabled&& !isNetworkEnabled){
//no network enable
}else {
this.canGetLocation = true;
if(isNetworkEnabled){
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network","Network");
if(locationManager != null){
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if(location != null){
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
if(isGPSEnabled){
if(location == null){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if(location != null){
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
} catch (Exception e){
e.printStackTrace();
}
return location;
}
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
return latitude;
}
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
return longitude;
}
public boolean canGetLocation(){
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
そしてマイリスト活動
public class Mobil extends ListFragment implements LocationListener{
GPSTracker gps;
private static final String url = "http://10.0.2.2/tambalban/car.php";
JSONArray tambalban = null;
ArrayList<HashMap<String, String>> listMobil = new ArrayList<HashMap<String, String>>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new getJSONData().execute();
}
public class getJSONData extends
AsyncTask<String, Integer, ArrayList<HashMap<String, String>>> {
@Override
protected ArrayList<HashMap<String, String>> doInBackground(
String... params) {
JSONParser jParser = new JSONParser();
JSONObject json = jParser.getJSONFromURL(url);
gps = new GPSTracker(getActivity()); // is it right calling from GPSTracker?
double lat_user = gps.getLatitude(); // get latitude, right?
double lng_user = gps.getLongitude();
System.out.println("lat_user : "+lat_user+""); // print in logcat return 0.00
System.out.println("lng_user : "+lng_user+"");// print in logcat return 0.00
try {
tambalban = json.getJSONArray(TAG_TAMBALBAN);
for (int i = 0; i < tambalban.length(); i++) {
JSONObject mtr = tambalban.getJSONObject(i);
String id_tb = mtr.getString(TAG_ID);
String name_tb = mtr.getString(TAG_NAMA);
String address_tb = mtr.getString(TAG_ALAMAT);
String telp_tb = mtr.getString(TAG_TELP);
String lat = mtr.getString(TAG_LAT);
String lng = mtr.getString(TAG_LNG);
double lat_tujuan = Double.parseDouble(lat);
double lng_tujuan = Double.parseDouble(lng);
double distance = hitungJarak(lat_user, lng_user, lat_tujuan, lng_tujuan);
distance = RoundDecimal(distance, 2);
String dist = Double.toString(distance)+" km";
HashMap<String, String> a = new HashMap<String, String>();
a.put(TAG_ID, id_tb);
a.put(TAG_NAMA, name_tb);
a.put(TAG_ALAMAT, address_tb);
a.put(TAG_TELP, telp_tb);
a.put(TAG_LAT, lat);
a.put(TAG_LNG, lng);
a.put(TAG_JARAK, dist);
listMobil.add(a);
}
} catch (JSONException e) {
e.printStackTrace();
}
return listMobil;
}
private double RoundDecimal(double distance, int i) {
BigDecimal bd = new BigDecimal(distance);
bd = bd.setScale(i, 6);
return bd.doubleValue();
}
private double hitungJarak(double lat_user, double lng_user,
double lat_tujuan, double lng_tujuan) {
double dist;
double radius = 6371;
double dLat = Math.toRadians(lat_tujuan - lat_user);
double dLon = Math.toRadians(lng_tujuan- lng_user);
double a = Math.sin(dLat/2) * Math.sin(dLat /2)
+ Math.cos(Math.toRadians(lat_user)) * Math.cos(Math.toRadians(lat_tujuan))
* Math.sin(dLon/ 2) * Math.sin(dLon/2);
double c = 2 * Math.asin(Math.sqrt(a));
double valueResult = radius * c;
double km = valueResult/1;
DecimalFormat newFormat = new DecimalFormat("####");
int kmInDec = Integer.valueOf(newFormat.format(km));
dist = radius * c;
return dist;
}
@Override
protected void onPostExecute(
ArrayList<HashMap<String, String>> listMobil) {
// TODO Auto-generated method stub
super.onPostExecute(listMobil);
ListAdapter adapter = new SimpleAdapter(getActivity(), listMobil,
R.layout.list_item, new String[] { TAG_NAMA, TAG_ALAMAT, TAG_JARAK },
new int[] { R.id.namatb, R.id.alamattb,R.id.jarak });
setListAdapter(adapter);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
return inflater.inflate(R.layout.list_fragment, container, false);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
super.onListItemClick(l, v, position, id);
String pilih = getListAdapter().getItem(position).toString();
Toast.makeText(getActivity(),
pilih,
Toast.LENGTH_LONG).show();
Intent i = new Intent(getActivity(), DetailDaftar.class);
Bundle bundle = new Bundle();
bundle.putString("Selected", pilih);
i.putExtras(bundle);
startActivity(i);
}
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
Sytem.out.println を使用して確認すると、緯度と経度の両方が 0.00 を返します。現在の場所を呼び出すのは間違っていますか? 助けてくれてありがとう。