如何刷新地图上的标记? [英] How to refresh the Marker on the Map?
问题描述
我在地图上只有2个标记
1-我想用最大缩放比例来显示标记
2-我希望用定时器刷新标记位置。
我想用这个排序来加载A和B的信息从服务器。我是一个Beginer
这是我的代码:
$ p $ import android .content.Context;
导入android.content.SharedPreferences;
导入android.content.pm.PackageManager;
导入android.support.v4.app.ActivityCompat;
导入android.support.v4.app.FragmentActivity;
导入android.os.Bundle;
导入android.util.Log;
导入android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.maps.CameraUpdateFactory;
导入com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
导入com.google.android.gms.maps.model.MarkerOptions;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class Test扩展FragmentActivity实现OnMapReadyCallback {
RequestQueue requestQueue;
字符串b_lat,b_lon,a_lat,a_lon;
私有GoogleMap mMap;
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
SupportMapFragment mapFragment =(SupportMapFragment)getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@覆盖
public void onMapReady(GoogleMap googleMap){
mMap = googleMap ;
LatLng a_local = new LatLng(Double.parseDouble(a_lat),Double.parseDouble(a_lon));
LatLng b_local = new LatLng(Double.parseDouble(b_lat),Double.parseDouble(b_lon));
mMap.addMarker(new MarkerOptions()。position(a_local).title(a)
.snippet(xxx)
.icon(BitmapDescriptorFactory.fromResource R.drawable.marker_a)))showInfoWindow();
mMap.addMarker(new MarkerOptions()。position(b_local).title(b)
.snippet(yyy)
.icon(BitmapDescriptorFactory.fromResource R.drawable.marker_b)))showInfoWindow();
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
mMap.getUiSettings()。setZoomControlsEnabled(true);
mMap.getUiSettings()。setCompassEnabled(true);
mMap.getUiSettings()。setAllGesturesEnabled(true);
mMap.getUiSettings()。setMyLocationButtonEnabled(true);
if(ActivityCompat.checkSelfPermission(this,android.Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED&&& ActivityCompat.checkSelfPermission(this,android.Manifest.permission.ACCESS_COARSE_LOCATION)!= PackageManager.PERMISSION_GRANTED){
return;
}
mMap.setMyLocationEnabled(true);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(a_local,16));
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener(){
@Override
public void onMapClick(LatLng latLng){
Toast.makeText(Test.this,latLng .latitude +,+ latLng.longitude,Toast.LENGTH_SHORT).show();
}
});
}
public void a_b_locations(){
try {
SharedPreferences myshared = getSharedPreferences(file,Context.MODE_PRIVATE);
a_lat = myshared.getString(a_lat,);
a_lon = myshared.getString(a_lon,);
b_lat = myshared.getString(b_lat,);
b_lon = myshared.getString(b_lon,);
}
catch(例外e){
return;
@Override
保护无效的onResume(){
super.onResume();
a_b_locations();
public void load_locations_from_server(){
String URL =http://myweb.com;
requestQueue = Volley.newRequestQueue(this);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET,URL,
new Response.Listener< JSONObject>(){
@Override $ b $ public void onResponse(JSONObject response){
尝试{
JSONArray jsonArray = response.getJSONArray(locations);
for(int i = 0; i< jsonArray.length(); i ++){
JSONObject respons = jsonArray.getJSONObject(i);
a_lat = respons.getString(a_lat);
a_lon = respons.getString(a_lon) ;
b_lat = respons.getString(b_lat);
b_lon = respons.getString(b_lon);
}
} catch (JSONException e) {
e.printStackTrace();
$ b},新的Response.ErrorListener(){
@Override
public void onErrorResponse(VolleyError error){
Log .e(VOLLEY,ERROR);
}
}
);
requestQueue.add(jsonObjectRequest);
$ b
您需要在地图准备好之后调用 load_locations_from_server()
方法,该方法位于 onMapReady()
方法中。
请阅读 https: //developers.google.com/maps/documentation/android-api/start
要设置标记的新位置,只需使用:
Marker.setPosition(LatLng latlng);
所以您需要为这些标记创建两个变量。
私人标记mMarkerA;
private Marker mMarkerB;
然后在你的onMapReady()中初始化它们:
pre > @Override
public void onMapReady(GoogleMap googleMap){
mMap = googleMap;
...
mMarkA = mMap.addMarker(new MarkerOptions()。position(a_local).title(a)
.snippet(xxx )
.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_yellow)))。showInfoWindow();
mMarkB = mMap.addMarker(new MarkerOptions()。position(b_local).title(b)
.snippet(yyy)
.icon(BitmapDescriptorFactory。 fromResource(R.drawable.markerb)))showInfoWindow();
...
}
然后,您可以刷新它们从服务器的位置:
a_lat = respons.getString(a_lat);
a_lon = respons.getString(a_lon);
b_lat = respons.getString(b_lat);
b_lon = respons.getString(b_lon);
//刷新标记
mMarkerA.setPosition(new LatLng(a_lat,a_lon));
mMarkerA.setPosition(new LatLng(b_lat,b_lon));
显示两个标记
您可以使用 LatLngBounds
类似以下方法:
private void zoomToShowBothPoints(LatLng firstLatLng,LatLng secondLatLng){
LatLngBounds bounds =
new LatLngBounds.Builder().include(firstLatLng).include(secondLatLng).build();
Point displaySize = new Point();
getWindowManager()。getDefaultDisplay()。getSize(displaySize);
mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds,displaySize.x - 20,displaySize.y - 20,50));
}
I have just 2 Markers on the Map
1- I want to show the bothe markers with max zoom as possible
2- I want after that refresh the markers position with a timer for example.
I want to use the volley to load the infos of A and B from server. I am a Beginer
Here is my Code :
import android.content.Context;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class Test extends FragmentActivity implements OnMapReadyCallback {
RequestQueue requestQueue;
String b_lat, b_lon, a_lat, a_lon;
private GoogleMap mMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
LatLng a_local = new LatLng(Double.parseDouble(a_lat), Double.parseDouble(a_lon));
LatLng b_local = new LatLng(Double.parseDouble(b_lat), Double.parseDouble(b_lon));
mMap.addMarker(new MarkerOptions().position(a_local).title("a")
.snippet("xxx")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_a))).showInfoWindow();
mMap.addMarker(new MarkerOptions().position(b_local).title("b")
.snippet("yyy")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_b))).showInfoWindow();
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setCompassEnabled(true);
mMap.getUiSettings().setAllGesturesEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
mMap.setMyLocationEnabled(true);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(a_local,16));
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
@Override
public void onMapClick(LatLng latLng) {
Toast.makeText(Test.this,latLng.latitude + ", " +latLng.longitude, Toast.LENGTH_SHORT).show();
}
});
}
public void a_b_locations(){
try {
SharedPreferences myshared = getSharedPreferences("file", Context.MODE_PRIVATE);
a_lat= myshared.getString("a_lat","");
a_lon= myshared.getString("a_lon","") ;
b_lat= myshared.getString("b_lat","") ;
b_lon= myshared.getString("b_lon","") ;
}
catch(Exception e) {
return ;
}
}
@Override
protected void onResume() {
super.onResume();
a_b_locations();
}
public void load_locations_from_server() {
String URL="http://myweb.com";
requestQueue = Volley.newRequestQueue(this);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, URL,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("locations");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject respons = jsonArray.getJSONObject(i);
a_lat=respons.getString("a_lat");
a_lon=respons.getString("a_lon");
b_lat=respons.getString("b_lat");
b_lon=respons.getString("b_lon");
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("VOLLEY", "ERROR");
}
}
);
requestQueue.add(jsonObjectRequest);
}
}
You need to call load_locations_from_server()
method after map ready which is in onMapReady()
method.
Read more at https://developers.google.com/maps/documentation/android-api/start
To set the new location of marker, you just need to use:
Marker.setPosition(LatLng latlng);
So you need to create two variables for the markers.
private Marker mMarkerA; private Marker mMarkerB;
Then in your onMapReady(), initialize them:
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
...
mMarkerA = mMap.addMarker(new MarkerOptions().position(a_local).title("a")
.snippet("xxx")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_yellow))).showInfoWindow();
mMarkerB = mMap.addMarker(new MarkerOptions().position(b_local).title("b")
.snippet("yyy")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.markerb))).showInfoWindow();
...
}
Then, you can refresh them when you get the location from the server:
a_lat=respons.getString("a_lat");
a_lon=respons.getString("a_lon");
b_lat=respons.getString("b_lat");
b_lon=respons.getString("b_lon");
// refresh marker
mMarkerA.setPosition(new LatLng(a_lat, a_lon));
mMarkerA.setPosition(new LatLng(b_lat, b_lon));
Show Both Marker
To show both marker with extra padding, you can use LatLngBounds
like the following method:
private void zoomToShowBothPoints(LatLng firstLatLng, LatLng secondLatLng) {
LatLngBounds bounds =
new LatLngBounds.Builder().include(firstLatLng).include(secondLatLng).build();
Point displaySize = new Point();
getWindowManager().getDefaultDisplay().getSize(displaySize);
mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, displaySize.x - 20, displaySize.y - 20, 50));
}
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