Java Android将Json对象添加到google标记
我试图将从API读取的数据添加为标记的Lat和Long 我似乎无法理解它应该如何工作,我所想的一切都失败了 这是我的密码: package com.fly.planeJava Android将Json对象添加到google标记,java,android,json,google-maps,Java,Android,Json,Google Maps,我试图将从API读取的数据添加为标记的Lat和Long 我似乎无法理解它应该如何工作,我所想的一切都失败了 这是我的密码: package com.fly.plane import java.util.ArrayList; import java.util.HashMap; import java.util.List; import org.json.JSONArray; import org.json.JSONException; import
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.fly.plane.R;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
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.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.R.array;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class MyMapActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get data JSON
private static String url = "http://edmundgentle.com/snippets/flights/api.php";
// JSON Node speeds
private static final String TAG_data = "data";
private static final String TAG_BEARING = "bearing";
private static final String TAG_speed = "speed";
private static final String TAG_ARR = "arr";
private static final String TAG_ARR_TIME = "time";
private static final String TAG_ARR_LAT = "lat";
private static final String TAG_ARR_LON = "lon";
private static final String TAG_DEP = "dep";
private static final String TAG_DEP_TIME = "time";
private static final String TAG_DEP_LAT = "lat";
private static final String TAG_DEP_LON = "lon";
// data JSONArray
JSONArray data = null;
// Hashmap for ListView (just for testing)
ArrayList<HashMap<String, String>> contactList;
// Hashmap for ListView
ArrayList<String> ct;
private GoogleMap mMap;
public double latt = 0;
public double lng = 0;
public ArrayList<Integer> dLat;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_map);
// create markers
mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
List<Marker> markers = new ArrayList<Marker>();
for (int i = 0; i < 5 ; i++)
{
Marker marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(latt, lng))
.title("Hello world")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));
markers.add(marker);
latt = Double.parseDouble(ct.get(i));
lng = i;
}
contactList = new ArrayList<HashMap<String, String>>();
ct = new ArrayList<String>();
//ListView lv = getListView();
new Getdata().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class Getdata extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MyMapActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
HTTPHandler sh = new HTTPHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, HTTPHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
data = jsonObj.getJSONArray(TAG_data);
// looping through All data
for (int i = 0; i < data.length(); i++) {
JSONObject c = data.getJSONObject(i);
String bearing = c.getString(TAG_BEARING);
String speed = c.getString(TAG_speed);
// departure node is JSON Object
JSONObject dep = c.getJSONObject(TAG_DEP);
String dtime = dep.getString(TAG_DEP_TIME);
String dlat = dep.getString(TAG_DEP_LAT);
String dlon = dep.getString(TAG_DEP_LON);
//dLat.add( Integer.parseInt(dep.getString(TAG_DEP_LAT)));
// arrival node is JSON Object
JSONObject arr = c.getJSONObject(TAG_ARR);
String atime = arr.getString(TAG_ARR_TIME);
String alat = arr.getString(TAG_ARR_LAT);
String alon = arr.getString(TAG_ARR_LON);
ArrayList<String> test = new ArrayList<String>();
test.add(alat);
ct.addAll(test);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_BEARING, bearing);
contact.put(TAG_speed, speed);
contact.put(TAG_DEP_TIME, dtime);
contact.put("atime", atime);
// adding contact to contact list
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MyMapActivity.this, contactList,
R.layout.list_item, new String[] { TAG_speed,TAG_DEP_TIME, "atime"
}, new int[] { R.id.speed,
R.id.departure, R.id.arrival });
setListAdapter(adapter);
}
}
}
我能够读取所有的数据,并将其显示在屏幕上(目前仅用于验证目的)。我遇到的问题是,将这些数据设置为每个标记的Lat和Lon
编辑:我可以阻止它导致错误,但它将不再打印标记。(我猜contactList.size在尝试创建标记时为0,这导致它永远不会运行for循环,如果我将其更改为i,LatLng类的构造函数将2个double作为参数。您应该使用
latt = Double.parseDouble(..);
lng = Double.parseDouble(..);
您当前正在将i(0-4)的值分配给lng。请确保正确分配从json对象检索到的lat和lng值。您应该将其放入HashMap字符串列表中
String alat = arr.getString(TAG_ARR_LAT);
String alon = arr.getString(TAG_ARR_LON);
contact.put(TAG_ARR_LAT, atime);
contact.put(TAG_ARR_LON, atime);
之后,在检索纬度和经度时,请使用此
for (int i = 0; i < contactList.size ; i++)
{
String lat = contactList.get(i).get(TAG_ARR_LAT);
String lng = contactList.get(i).get(TAG_ARR_LON);
// Now parse it in double
double latitude = Double.parseDouble(lat);
double longitude = Double.parseDouble(lng);
Marker marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(latitude, longitude))
.title("Hello world")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));
markers.add(marker);
}
for(int i=0;i
在这里编写Json…这就是我遇到的问题,我将Json作为字符串获取,并且很难将其转换为Double以供placemarker使用。如果将其作为字符串转换为Double,这会阻止它崩溃,但它不会放置标记,我怀疑是因为它只放置oncreate,不确定我将如何告诉它放置/向上不过,约会标记经常出现。
String alat = arr.getString(TAG_ARR_LAT);
String alon = arr.getString(TAG_ARR_LON);
contact.put(TAG_ARR_LAT, atime);
contact.put(TAG_ARR_LON, atime);
for (int i = 0; i < contactList.size ; i++)
{
String lat = contactList.get(i).get(TAG_ARR_LAT);
String lng = contactList.get(i).get(TAG_ARR_LON);
// Now parse it in double
double latitude = Double.parseDouble(lat);
double longitude = Double.parseDouble(lng);
Marker marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(latitude, longitude))
.title("Hello world")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));
markers.add(marker);
}