我们需要程序从数据库中获取数据（经度和纬度），并将具有这些坐标的标记添加到地图中
MapsActivity：
package ilfarsif.myapp_places;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity2 extends FragmentActivity {
private GoogleMap mMap; // Might be null if Google Play services APK is not available.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps_activity2);
setUpMapIfNeeded();
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
/**
* Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
* installed) and the map has not already been instantiated.. This will ensure that we only ever
* call {@link #setUpMap()} once when {@link #mMap} is not null.
* <p/>
* If it isn't installed {@link SupportMapFragment} (and
* {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
* install/update the Google Play services APK on their device.
* <p/>
* A user can return to this FragmentActivity after following the prompt and correctly
* installing/updating/enabling the Google Play services. Since the FragmentActivity may not
* have been completely destroyed during this process (it is likely that it would only be
* stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
* method in {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
/**
* This is where we can add markers or lines, add listeners or move the camera. In this case, we
* just add a marker near Africa.
* <p/>
* This should only be called once and when we are sure that {@link #mMap} is not null.
*/
private void setUpMap() {
//mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
String arrayUrl = "id[]=1&id[]=2&id[]=3&id[]=4";
SuggestionAdapter sa = new SuggestionAdapter();
sa.execute(arrayUrl);
}
}
SuggestionAdapter：
package ilfarsif.myapp_places;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Filter;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
public class SuggestionAdapter extends AsyncTask<String, Void, String> {
public static String LOG_TAG = "my_log";
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String resultJson = "";
@Override
protected String doInBackground(String... Params) {
// получаем данные с внешнего ресурса
try {
String strUrl = "";
if( Params.length > 0 ){
strUrl = Params[0];
}
URL url = new URL("http://www.p89742wj.bget.ru/test3.php?"+ strUrl);//id[]=1&id[]=2&id[]=3
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line);
}
resultJson = buffer.toString();
} catch (Exception e) {
e.printStackTrace();
}
return resultJson;
}
@Override
protected void onPostExecute(String strJson) {
super.onPostExecute(strJson);
// выводим целиком полученную json-строку
Log.d(LOG_TAG, strJson);
JSONObject dataJsonObj = null;
String idByMagName = "";
try {
dataJsonObj = new JSONObject(strJson);
//--
JSONObject mag = dataJsonObj.getJSONObject("idMag");
idByMagName = mag.getString("idd");
Log.d(LOG_TAG, "Дешевый Магазин: " + idByMagName);
//--
JSONArray products = dataJsonObj.getJSONArray("Mag");
for (int i = 0; i < products.length(); i++) {
JSONObject obj = products.getJSONObject(i);
String Id = obj.getString("id_mag");
String Adress = obj.getString("adress");
//String LL = obj.getString("latlng");
String Lat=obj.getString("lat");
String Lng=obj.getString("lng");
double latitude = Double.parseDouble(Lat);//String LL ConvertTO LLDouble
double longitude = Double.parseDouble(Lng);
int iddd = Integer.parseInt(Id);
int dii = Integer.parseInt(idByMagName);
Log.d(LOG_TAG, "id: " + Id);
Log.d(LOG_TAG, "adress: " + Adress);
Log.d(LOG_TAG, "lat: " + Lat);
Log.d(LOG_TAG, "lang: " + Lng);
/* LatLng latLng_new = new LatLng(latitude, longitude);
mMap.addMarker(new MarkerOptions().position(latLng_new).title("Marker 1"));*/
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
建议我们将此循环插入代码中，但无效。问题在于，mMap地图片段未在RecommendationionAdapter中定义，并且该代码无法在MapsActivity中工作
for (int i = 0; i < products.length(); i++) {
JSONObject obj = products.getJSONObject(i);
String Id = obj.getString("id_mag");
String Adress = obj.getString("adress");
//String LL = obj.getString("latlng");
String Lat=obj.getString("lat");
String Lng=obj.getString("lng");
double latitude = Double.parseDouble(Lat);
//String LL ConvertTO LLDouble
double longitude = Double.parseDouble(Lng);
int iddd = Integer.parseInt(Id);
int dii = Integer.parseInt(idByMagName);
Marker melbourne = mMap.addMarker(new MarkerOptions()
.position(new LatLng(latitude , longitude))
.title("Melbourne")
.snippet("Population: 4,137,400"));
}