Develop Reference

Picking the right Zoom level for different cities in GoogleMaps

I have an activity implementing OnMapReadyCallback to display some markers.
Before opening the map i provide a target city which i'd like to look at closer on the map basically by calling :
LatLng currentCity = new LatLng(cityLat,cityLng)
CameraUpdate location = CameraUpdateFactory.newLatLngZoom(currentCity,13);
googleMap.animateCamera(location);
The main problem here is that the zoom level is just an arbitrary number which works fine for some city and bad for others (Too zoomed in, Not enough zoomed in).
What i would like to achieve is to determine the zoom level dynamically depending on the city in the same way Google Maps does.
I know that the bigger the ViewPort of the city is, the smaller the zoom needs to be but i can't find a method to get the ViewPort for a given city and then changing the zoom level accordingly
EDIT : I was thinking about using a Geocoder to get a list of adress using the latitude and longitude of the city using
List<Address> addresses = mGeocoder.getFromLocation(Lat,Lon,maxLimit);
and then iterating over this list to find out the outermost adresses avaible for that city, in order to build a LatLngBounds to pass at setLatLngBoundsForCameraTarget() method.
The main problem with this approach is that, once again, the "maxLimit" is arbitrary and needs to be quite big for a big city, eventually returning a really big List

You can retrieve a view port for the city from the Geocoding API reverse geocoding response.
You should execute HTTP request to retrieve city view port from your activity. Once you receive the response you can construct the LatLngBounds instance and move camera accordingly.
Sample reverse geocoding request that gets city from coordinates is the following
https://maps.googleapis.com/maps/api/geocode/json?latlng=47.376887%2C8.541694&result_type=locality&key=YOUR_API_KEY
I wrote a small example for Map activity that receives lat and lng from the intent, executes the reverse geocoding HTTP request using the Volley library and moves camera to show the city view port.
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private float lat;
private float lng;
private String name;
private RequestQueue mRequestQueue;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent i = getIntent();
this.lat = i.getFloatExtra("lat", 0);
this.lng = i.getFloatExtra("lng", 0);
this.name = i.getStringExtra("name");
mRequestQueue = Volley.newRequestQueue(this);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng pos = new LatLng(this.lat, this.lng);
mMap.addMarker(new MarkerOptions().position(pos).title(this.name));
mMap.moveCamera(CameraUpdateFactory.newLatLng(pos));
this.fetchReverseGeocodeJson();
}
private void fetchReverseGeocodeJson() {
// Pass second argument as "null" for GET requests
JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET,
"https://maps.googleapis.com/maps/api/geocode/json?latlng=" + this.lat + "%2C" + this.lng + "&result_type=locality&key=AIzaSyBrPt88vvoPDDn_imh-RzCXl5Ha2F2LYig",
null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
String status = response.getString("status");
if (status.equals("OK")) {
JSONArray results = response.getJSONArray("results");
JSONObject item = results.getJSONObject(0);
JSONObject geom = item.getJSONObject("geometry");
JSONObject bounds = geom.getJSONObject("viewport");
JSONObject ne = bounds.getJSONObject("northeast");
JSONObject sw = bounds.getJSONObject("southwest");
LatLngBounds mapbounds = new LatLngBounds(new LatLng(sw.getDouble("lat"),sw.getDouble("lng")),
new LatLng(ne.getDouble("lat"), ne.getDouble("lng")));
mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(mapbounds, 0));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
}
}
);
/* Add your Requests to the RequestQueue to execute */
mRequestQueue.add(req);
}
}
You can find a complete sample project at github:
https://github.com/xomena-so/so44735477
Hope this helps!

How using offline map in android

I want download a particular city in my app. How can do this? There is another problem, too: when I use SDK of Mapbox 4.1.1 I can't add the class BoundingBox.
I have a problem, a code that exists on their site to download the map is not based just once. I have to stop running the program, and when I re-run it the map does not load again.
This is my code :
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
MapboxAccountManager.start(this, getString(R.string.access_token));
// This contains the MapView in XML and needs to be called after the account manager
setContentView(R.layout.activity_offline_simple);
mapView = (MapView) findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {
#Override
public void onMapReady(MapboxMap mapboxMap) {
// Set up the OfflineManager
offlineManager = OfflineManager.getInstance(SimpleOfflineMapActivity.this);
// Create a bounding box for the offline region
LatLngBounds latLngBounds = new LatLngBounds.Builder()
.include(new LatLng(13.1,32.6)) // Northeast
.include(new LatLng(13.6,32.9)) // Southwest
.build();
// Define the offline region
OfflineTilePyramidRegionDefinition definition = new OfflineTilePyramidRegionDefinition(
mapView.getStyleUrl(),
latLngBounds,
10,
20,
SimpleOfflineMapActivity.this.getResources().getDisplayMetrics().density);
// Set the metadata
byte[] metadata;
try {
JSONObject jsonObject = new JSONObject();
jsonObject.put(JSON_FIELD_REGION_NAME, "Triopli Libya");
String json = jsonObject.toString();
metadata = json.getBytes(JSON_CHARSET);
} catch (Exception exception) {
Log.e(TAG, "Failed to encode metadata: " + exception.getMessage());
metadata = null;
}
// Create the region asynchronously
offlineManager.createOfflineRegion(
definition,
metadata,
new OfflineManager.CreateOfflineRegionCallback() {
#Override
public void onCreate(OfflineRegion offlineRegion) {
offlineRegion.setDownloadState(OfflineRegion.STATE_ACTIVE);
// Display the download progress bar
progressBar = (ProgressBar) findViewById(R.id.progress_bar);
startProgress();
// Monitor the download progress using setObserver
offlineRegion.setObserver(new OfflineRegion.OfflineRegionObserver() {
#Override
public void onStatusChanged(OfflineRegionStatus status) {
// Calculate the download percentage and update the progress bar
double percentage = status.getRequiredResourceCount() >= 0
? (100.0 * status.getCompletedResourceCount() / status.getRequiredResourceCount()) :
0.0;
if (status.isComplete()) {
// Download complete
endProgress("Region downloaded successfully.");
} else if (status.isRequiredResourceCountPrecise()) {
// Switch to determinate state
setPercentage((int) Math.round(percentage));
}
}
#Override
public void onError(OfflineRegionError error) {
// If an error occurs, print to logcat
Log.e(TAG, "onError reason: " + error.getReason());
Log.e(TAG, "onError message: " + error.getMessage());
}
#Override
public void mapboxTileCountLimitExceeded(long limit) {
// Notify if offline region exceeds maximum tile count
Log.e(TAG, "Mapbox tile count limit exceeded: " + limit);
}
});
}
#Override
public void onError(String error) {
Log.e(TAG, "Error: " + error);
}
});
}
});
}

Your offline region specified is exceeding the 6000 tile count limit. You can read more about this on our help pages and use the tile calculator to either reduce the region size or change the zoom levels downloaded.

Or you can use setOfflineMapboxTileCountLimit on newer versions
offlineManager.setOfflineMapboxTileCountLimit(20000000);

Mapbox Offlne (Android)

I'm working on MapBox off line. The code was OK, able to download map but after adding some peice of code which have nothing to do with the map, the download stop to work and the give an HTTP401 Error.
I've noticed that depending on where you call MapboxAccountManager.start sometimes it fails.
Here's the code:
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
DB_Handler db_ansb = new DB_Handler(Init_Carte.this,null,null,1);
// Get data from DB, about the map
HashMap<String, String> data_mapbox = db_ansb.do_get_mapbox(0);
the_mapbox_token = data_mapbox.get("tmapbox_token");
the_mapbox_style = data_mapbox.get("tmapbox_style");
the_mapbox_zoom_min = Integer.parseInt(data_mapbox.get("tmapbox_zoom_min"));
the_mapbox_zoom_max = Integer.parseInt(data_mapbox.get("tmapbox_zoom_max"));
the_mapbox_inter = Double.parseDouble(data_mapbox.get("tmapbox_inter"));
OfflineManager offlineManager = OfflineManager.getInstance(this);
MapboxAccountManager.start(this,the_mapbox_token);
setContentView(R.layout.activity_init_carte);
// Menu with APP compat
// https://developer.android.com/training/appbar/setting-up.html
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
// Find our truck GPS position for road map
HashMap<String, String> my_truck = db_ansb.do_get_my_truck();
String str_truck_lagps = my_truck.get("frota_lagps");
String str_truck_logps = my_truck.get("frota_logps");
the_lagps_truck = Double.parseDouble(str_truck_lagps);
the_logps_truck = Double.parseDouble(str_truck_logps);
// Find accident location for road map
HashMap<String, String> my_inter = db_ansb.do_get_inter_resume();
String str_inter_lagps = my_inter.get("inter_lagps");
String str_inter_logps = my_inter.get("inter_logps");
the_lagps_inter = Double.parseDouble(str_inter_lagps);
the_logps_inter = Double.parseDouble(str_inter_logps);
// Compute area to get
HashMap<String, Double> data_gps_inter = db_ansb.do_get_bounds_inter(the_lagps_inter,the_logps_inter,the_mapbox_inter);
final double inter_lagps_ne = data_gps_inter.get("inter_max_lagps"); // Nord Est
final double inter_logps_ne = data_gps_inter.get("inter_max_logps");
final double inter_lagps_so = data_gps_inter.get("inter_min_lagps"); // Sud Ouest
final double inter_logps_so = data_gps_inter.get("inter_min_logps");
// Display what we're doing
tmp_id_msg = (TextView) findViewById(R.id.txt_action);
tmp_id_msg.setText(R.string.str_telechargement_carte);
// Create zone
LatLngBounds latLngBounds = new LatLngBounds.Builder()
.include(new LatLng(inter_lagps_ne, inter_logps_ne)) // Northeast
.include(new LatLng(inter_lagps_so, inter_logps_so)) // Southwest
.build();
OfflineTilePyramidRegionDefinition definition = new OfflineTilePyramidRegionDefinition(
the_mapbox_style,
latLngBounds,
the_mapbox_zoom_min,
the_mapbox_zoom_max,
(Init_Carte.this).getResources().getDisplayMetrics().density);
byte[] metadata;
try
{
JSONObject jsonObject = new JSONObject();
jsonObject.put(JSON_FIELD_REGION_NAME, "Carte");
String json = jsonObject.toString();
metadata = json.getBytes(JSON_CHARSET);
} catch (Exception e)
{
Log.e("TAG", "Failed to encode metadata: " + e.getMessage());
metadata = null;
}
// Get data
offlineManager.createOfflineRegion(definition, metadata, new OfflineManager.CreateOfflineRegionCallback()
{
#Override
public void onCreate(OfflineRegion offlineRegion)
{
offlineRegion.setDownloadState(OfflineRegion.STATE_ACTIVE);
// Monitor the download progress using setObserver
offlineRegion.setObserver(new OfflineRegion.OfflineRegionObserver()
{
#Override
public void onStatusChanged(OfflineRegionStatus status)
{
Log.i("DBUG","onStatusChanged");
// Calculate the download percentage and update the progress bar
double percentage = status.getRequiredResourceCount() >= 0 ?
(100.0 * status.getCompletedResourceCount() / status.getRequiredResourceCount()) :
0.0;
long long_pourcentage = Math.round(percentage);
String str_pourcentage = Long.toString(long_pourcentage)+" %";
// Display on screen
tmp_id_valeur = (TextView) findViewById(R.id.val_action);
tmp_id_valeur.setText(str_pourcentage);
Log.i("DBUG",str_pourcentage+"%");
if (status.isComplete())
{
// OK so now, ask the road
do_get_trajet();
}
}
#Override
public void onError(OfflineRegionError error)
{
// If an error occurs, print to logcat
Log.i("DBUG", "onError reason: " + error.getReason());
Log.e("DBUG", "onError message: " + error.getMessage());
}
#Override
public void mapboxTileCountLimitExceeded(long limit)
{
// Notify if offline region exceeds maximum tile count
Log.i("DBUG", "Mapbox tile count limit exceeded: " + limit);
}
});
}
#Override
public void onError(String error)
{
Log.e("TAG", "Error: " + error);
}
});
}
I enter the Aysnc part, get 3 or 4 times
Log.i("DBUG",str_pourcentage+"%");
with a value of 0% then get I get:
I/System.out: [CDS]rx timeout:10000
D/NativeCrypto: ssl=0x619629c8 sslWrite buf=0x41e60068 len=222 write_timeout_millis=0
D/NativeCrypto: ssl=0x619629c8 sslRead buf=0x41e60068 len=8192,timeo=10000
I/DBUG: onError reason: REASON_OTHER
E/DBUG: onError message: HTTP status code 401
D/com.mapbox.mapboxsdk.http.HTTPRequest: [HTTP] Request with response code = 401: Unauthorized
I've noticed same strange behaviour on another page: depending on the fact you perform or not, action before of after MapboxAccountManager.start(this,the_mapbox_token); it works or not.
Notice the token is correct.
Any idea?
After changing the token in our DB, it was OK but only for a short time: I was able to download 26% of the map and then, I get again the HTTP 401 message...

Found. In fact there is a small mistake in the code that help me understand: how can this code work sometimes, as I call
OfflineManager offlineManager = OfflineManager.getInstance(this);
MapboxAccountManager.start(this,the_mapbox_token);
so as I call the init after the use of the Lib? In fact all example at Mapbox are made with one activity performing all the jobs. So when you have more than one activity using Mapbox, you quickly believe you need to put a MapboxAccountManager.start in each ones. Which is wrong. In that case (more than one activity), you must call MapboxAccountManager.start at App level. Like that:
public class App_Start extends Application
{
#Override
public void onCreate()
{
super.onCreate();
String the_mapbox_token = "pk.eyJ1IjoiYW5.....";
MapboxAccountManager.start(this,the_mapbox_token);
}
public void customAppMethod()
{
// Custom application method
}
}
and add this class at application level on your Manifest:
<application android:icon="#drawable/ic_launcher" android:label="#string/app_name" android:theme="#style/AppTheme" android:name="net.ansb_brasil.xxxx.App_Start">
Concerning the fact the second activity was performing two times the download, it came from the fact the if (status.isComplete()) part of the onStatusChanged() is always called two times. Seems to be a bug in the Lib. On some example at Mapbox, they use a boolean flag in order to avoid taking two times this call in account.
As my first activity was downloading one map and then call a second activity for a second map, this "double call" had as result two call for the second activity and so many troubles.
Hope this will avoid headaches to others

Android volley - Unexpected response code 500

I am trying to edit an already registered addresses on my application, but I'm getting this error when I try to do that.
private void callServiceToEditAddress(String flatNo, String apartmentName, String landmark, String pincode) {
HashMap<String, String> hashMap = new HashMap<>();
hashMap.put("id", addressID);
hashMap.put("flat_no", flatNo);
hashMap.put("apartment_name", apartmentName);
hashMap.put("lanmark", landmark);
hashMap.put("pincode", pincode);
hashMap.put("state", selectedState);
hashMap.put("city", ID_city);
hashMap.put("location", ID_locality);
hashMap.put("country", "2");
new VolleyHelper(getActivity()).post("editAddress/", hashMap, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
mAddresshasbeenAdded.newAddressHasbeenAdded();
CroutonUtil.showCroutonMessage(getActivity(), success, CroutonUtil.CROUTON_STYLE_CONFIRM);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
}
My Log cat:
E/Volley: [365] BasicNetwork.performRequest: Unexpected response code 500 for link I'm using

i solved this by changing the permission for included files in my server side

I was actually able to solve my problem eventually. What happened is that this web service that I am using "editAddress" also needed another field that I was not providing inside hashMap. I made the changes and it worked fine.

I just change my url from
http
to
https
Then it works fine for me.

The parameters put into Hashmap and get in server side was misspelled, When I have corrected the words of both side with same spelling , The problem was gone, Alhamdulillah.

Android Geocoder get short name of admin area

When using the google maps API, for the admin area it gives you the long name and short name eg.
{
"long_name": "Victoria",
"short_name": "VIC",
"types": [
"administrative_area_level_1",
"political"
]
}
however when using android's native geocoder, I am only getting the long name (in this case "Victoria"). Is there a way to get the short name of an admin area in android, short of integrating the google maps geocoding API?

I'm gonna keep this short and simple, I have done my location implementation a little different. Since it took me a couple of hours to do this.
First I made a Map List to find the state name then convert it to the 2 letter code like so:
Map<String, String> states = new HashMap<>();
states.put("Alabama","AL");
states.put("Alaska","AK");
states.put("Alberta","AB");
states.put("American Samoa","AS");
states.put("Arizona","AZ");
states.put("Arkansas","AR");
states.put("Armed Forces (AE)","AE");
states.put("Armed Forces Americas","AA");
states.put("Armed Forces Pacific","AP");
states.put("British Columbia","BC");
states.put("California","CA");
states.put("Colorado","CO");
states.put("Connecticut","CT");
states.put("Delaware","DE");
states.put("District Of Columbia","DC");
states.put("Florida","FL");
states.put("Georgia","GA");
states.put("Guam","GU");
states.put("Hawaii","HI");
states.put("Idaho","ID");
states.put("Illinois","IL");
states.put("Indiana","IN");
states.put("Iowa","IA");
states.put("Kansas","KS");
states.put("Kentucky","KY");
states.put("Louisiana","LA");
states.put("Maine","ME");
states.put("Manitoba","MB");
states.put("Maryland","MD");
states.put("Massachusetts","MA");
states.put("Michigan","MI");
states.put("Minnesota","MN");
states.put("Mississippi","MS");
states.put("Missouri","MO");
states.put("Montana","MT");
states.put("Nebraska","NE");
states.put("Nevada","NV");
states.put("New Brunswick","NB");
states.put("New Hampshire","NH");
states.put("New Jersey","NJ");
states.put("New Mexico","NM");
states.put("New York","NY");
states.put("Newfoundland","NF");
states.put("North Carolina","NC");
states.put("North Dakota","ND");
states.put("Northwest Territories","NT");
states.put("Nova Scotia","NS");
states.put("Nunavut","NU");
states.put("Ohio","OH");
states.put("Oklahoma","OK");
states.put("Ontario","ON");
states.put("Oregon","OR");
states.put("Pennsylvania","PA");
states.put("Prince Edward Island","PE");
states.put("Puerto Rico","PR");
states.put("Quebec","PQ");
states.put("Rhode Island","RI");
states.put("Saskatchewan","SK");
states.put("South Carolina","SC");
states.put("South Dakota","SD");
states.put("Tennessee","TN");
states.put("Texas","TX");
states.put("Utah","UT");
states.put("Vermont","VT");
states.put("Virgin Islands","VI");
states.put("Virginia","VA");
states.put("Washington","WA");
states.put("West Virginia","WV");
states.put("Wisconsin","WI");
states.put("Wyoming","WY");
states.put("Yukon Territory","YT");
Then I appended it into the Location String result after doing all the hocus pocus to get the address like
Address address = addressList.get(0);
String state = states.get(address.getAdminArea());
result = address.getLocality() + ", " + state;
I hope you got this before I did, but I just decided to put this up for anyone else that needs it. I happened to be on this page when I fixed it.
NOTE: The Map(not really a Location Map) List has Canada "states" and some other places that use abbreviations.

After some searching , I found one solution for that
String url = "http://maps.googleapis.com/maps/api/geocode/json?latlng=" + latitude + "," + longitude + "&sensor=true";
RequestQueue mVolleyQueue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
Log.i("response ", response);
JSONObject jsonObject = new JSONObject(response);
JSONArray arrayResult = jsonObject.getJSONArray("results");
JSONArray arrComponent = arrayResult.getJSONObject(0).getJSONArray("address_components");
for (int i = 0; i < arrComponent.length(); i++) {
JSONArray arrType = arrComponent.getJSONObject(i).getJSONArray("types");
for (int j = 0; j < arrType.length(); j++) {
if (arrType.getString(j).equals("administrative_area_level_1")) {
longname = arrComponent.getJSONObject(i).getString("long_name");
shortname = arrComponent.getJSONObject(i).getString("short_name");
Log.i("longname", longname);
Log.i("shortname", shortname);
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
stringRequest.setShouldCache(false);
stringRequest.setTag("Volley");
mVolleyQueue.add(stringRequest);
Happy Codding :)