我有一个应用程序，我必须从纬度和经度中获取用户的当前位置。对于这两个值，我必须得到小数点后的 12 位数字。
这是用于获取用户位置的 gps 跟踪器类：
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
private String locationUsing;
// 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);
// getting GPS status
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled)
{
// no network provider and GPS is enabled
Log.d("No GPS & Network", "no network provider and GPS is enabled");
}
else
{
this.canGetLocation = true;
//==================================================================================================================
//First it will try to get Location using GPS if it not going to get GPS
//then it will get Location using Tower Location of your network provider
//==================================================================================================================
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled)
{
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,MIN_TIME_BW_UPDATES,MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS", "Get loc using GPS");
if (locationManager != null)
{
Log.d("locationManager", "locationManager not null");
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null)
{
Log.d("location", "location Not null");
latitude = location.getLatitude();
longitude = location.getLongitude();
setLocationUsing("GPS");
}
}
}
//if GPS is Off then get lat/long using Network
if (isNetworkEnabled)
{
if (location == null)
{
Log.d("Network", "Get loc using Network");
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,MIN_TIME_BW_UPDATES,MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null)
{
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
setLocationUsing("Network");
}
}
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
/*public void stopUsingGPS()
{
if(locationManager != null)
{
locationManager.removeUpdates(GPSTracker.this);
}
}*/
/**
* Function to get latitude
* */
public double getLatitude()
{
if(location != null)
{
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude()
{
if(location != null)
{
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/Network enabled
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will launch 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) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
public String getLocationUsing() {
return locationUsing;
}
void setLocationUsing(String locationUsing) {
this.locationUsing = locationUsing;
}
}
这是我从中访问 GPSTracker 类的服务类：
public class MyAlarmService extends Service {
String device_id;
// GPSTracker class
GPSTracker gps;
String date_time;
String lat_str;
String lon_str;
static String response_str=null;
static String response_code=null;
@Override
public void onCreate() {
// TODO Auto-generated method stub
//Toast.makeText(this, "Service created", Toast.LENGTH_LONG).show();
//---get a Record---
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
//Toast.makeText(this, "MyAlarmService.onBind()", Toast.LENGTH_LONG).show();
return null;
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
//this.stopSelf();
//Toast.makeText(this, "Service Destroyed.", Toast.LENGTH_LONG).show();
}
@Override
public void onStart(Intent intent, int startId) {
// TODO Auto-generated method stub
super.onStart(intent, startId);
//Toast.makeText(this, "Service Started.", Toast.LENGTH_LONG).show();
//create class object
gps = new GPSTracker(this);
// check if GPS enabled
if(gps.canGetLocation())
{
//double latitude = gps.getLatitude();
double latitude = gps.getLatitude();
double longitude =gps.getLongitude();
String locationUsing = gps.getLocationUsing();
makeAToast("Latitude: "+latitude+", "+" Longitude: "+longitude);
final TelephonyManager tm =(TelephonyManager)getBaseContext().getSystemService(Context.TELEPHONY_SERVICE);
String deviceid = tm.getDeviceId();
Date formattedDate = new Date(System.currentTimeMillis());
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy hh:mm a", Locale.US);
date_time = sdf.format(formattedDate);
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
final String part_id=preferences.getString("Part_Id","");
final String Tracker = preferences.getString("Tracker_enabled","");
lat_str=""+latitude;
lon_str=""+longitude;
if(haveNetworkConnection())
{
if (Tracker.contains("true"))
{
Log.i("Tracker value: ", Tracker);
sendPostRequest(part_id,deviceid,lat_str,lon_str,date_time);
}
}
else
{
//Toast.makeText( getApplicationContext(),"No Internet connection or Wifi available",Toast.LENGTH_LONG).show();
}
}
else
{
// GPS or Network is not enabled
Toast.makeText(getApplicationContext(), "No Network or GPS", Toast.LENGTH_LONG).show();
}
}
@Override
public boolean onUnbind(Intent intent) {
// TODO Auto-generated method stub
// Toast.makeText(this, "Service binded", Toast.LENGTH_LONG).show();
return super.onUnbind(intent);
}
//=======================================================================================================
//check packet data and wifi
//=======================================================================================================
private boolean haveNetworkConnection()
{
boolean haveConnectedWifi = false;
boolean haveConnectedMobile = false;
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo[] netInfo = cm.getAllNetworkInfo();
for (NetworkInfo ni : netInfo)
{
if (ni.getTypeName().equalsIgnoreCase("WIFI"))
if (ni.isConnected())
haveConnectedWifi = true;
if (ni.getTypeName().equalsIgnoreCase("MOBILE"))
if (ni.isConnected())
haveConnectedMobile = true;
}
return haveConnectedWifi || haveConnectedMobile;
}
//=======================================================================================================
//checking packet data and wifi END
//=======================================================================================================
//sending async post request---------------------------------------------------------------------------------------
private void sendPostRequest(final String part_id, final String device_id,final String lat,final String lon, final String status_datetime) {
class SendPostReqAsyncTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... params) {
String result = "";
HttpClient hc = new DefaultHttpClient();
String message;
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(MyAlarmService.this);
final String url_first = preferences.getString("URLFirstPart","");
HttpPost p = new HttpPost(url_first+"SetTrakerLatLon");
JSONObject object = new JSONObject();
try {
object.put("PartId",part_id);
object.put("DeviceId",device_id);
object.put("Lat", lat);
object.put("Lon", lon);
object.put("DateTime", status_datetime);
} catch (Exception ex) {
}
try {
message = object.toString();
p.setEntity(new StringEntity(message, "UTF8"));
p.setHeader("Content-type", "application/json");
HttpResponse resp = hc.execute(p);
response_code=""+ resp.getStatusLine().getStatusCode();
InputStream inputStream = resp.getEntity().getContent();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder();
String bufferedStrChunk = null;
while((bufferedStrChunk = bufferedReader.readLine()) != null){
stringBuilder.append(bufferedStrChunk);
}
response_str= stringBuilder.toString();
Log.i("Tracker Response: ",response_str);
if (resp != null) {
if (resp.getStatusLine().getStatusCode() == 204)
result = "true";
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
}
}
SendPostReqAsyncTask sendPostReqAsyncTask = new SendPostReqAsyncTask();
sendPostReqAsyncTask.execute();
}
//-----------------------------------------------------------------------------------------------
//public void sendDataToServer(String time, String date) {
public void sendDataToServer(String deviceid,String date_time,String latitude,String longitude) {
// TODO Auto-generated method stub
try {
HttpClient client = new DefaultHttpClient();
String postURL = "http://192.168.1.60/trackme/trackservice.svc/SetLatLon?";
HttpPost post = new HttpPost(postURL);
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("mobileId", deviceid));
params.add(new BasicNameValuePair("lat", latitude));
params.add(new BasicNameValuePair("lon", longitude));
params.add(new BasicNameValuePair("udate", date_time));
UrlEncodedFormEntity ent = new UrlEncodedFormEntity(params,HTTP.UTF_8);
post.setEntity(ent);
Log.i("URL: ",EntityUtils.toString(ent));
HttpResponse responsePOST = client.execute(post);
HttpEntity resEntity = responsePOST.getEntity();
if (resEntity != null) {
Log.i("RESPONSE",EntityUtils.toString(resEntity));
}
} catch (Exception e) {
e.printStackTrace();
}
}
private StringBuilder inputStreamToString(InputStream is) {
String line="";
StringBuilder total=new StringBuilder();
BufferedReader buf=new BufferedReader(new InputStreamReader(is));
try {
while ((line=buf.readLine())!=null) {
total.append(line);
}
} catch (Exception e) {
// TODO: handle exception
makeAToast("Cannot connect to server from your device");
}
return total;
}
//to display a toast in case of message
public void makeAToast(String str) {
//yet to implement
Toast toast = Toast.makeText(this,str, Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER, 0, 0);
toast.show();
}
}
目前，我的纬度和经度都得到小数点后 4 位数字。我应该怎么做才能在纬度和经度值之后获得 12 位数字？