使用谷歌Places API的Web服务为Android特定搜索附近的地方附近、地方、API、Places
2023-09-06 06:42:18
作者：指点尔的青春丶
我想使用谷歌Places API的Web服务来限制地方搜索类型医院，但无法实现它。
的logcat
显示java.lang.NullPointerException 在com.ediode.graphics3d.ClinicFragment.sbMethod（ClinicFragment.java:174） 在com.ediode.graphics3d.ClinicFragment.onMa pready（ClinicFragment.java:95）
MainActivity
公共类ClinicFragment扩展AppCompatActivity工具 GoogleApiClient.ConnectionCallbacks，GoogleApiClient.OnConnectionFailedListener， LocationListener的， OnMa preadyCallback { 私人GoogleMap的mGoogleMap; SupportMapFragment mapFrag; LocationRequest mLocationRequest; GoogleApiClient mGoogleApiClient; 经纬度的latLng; 双mLatitude = 0; 双mLongitude = 0; @覆盖 保护无效的onCreate（捆绑savedInstanceState） { super.onCreate（savedInstanceState）; 的setContentView（R.layout.clinic_fragment）; mapFrag =（SupportMapFragment）getSupportFragmentManager（）findFragmentById（R.id.map）。 mapFrag.getMapAsync（本）; } @覆盖 公共无效onMa pready（GoogleMap的GoogleMap的） { mGoogleMap = GoogleMap的; mGoogleMap.setMyLocationEnabled（真）; buildGoogleApiClient（）; mGoogleApiClient.connect（）; StringBuilder的sbValue =新的StringBuilder（sbMethod（））; PlacesTask placesTask =新PlacesTask（）; placesTask.execute（sbValue.toString（））; } @覆盖 公共无效的onPause（） { super.onPause（）; //取消注册地点回调： 如果（mGoogleApiClient！= NULL） { LocationServices.FusedLocationApi.removeLocationUpdates（mGoogleApiClient，这一点）; } } 保护同步无效buildGoogleApiClient（） { mGoogleApiClient =新GoogleApiClient.Builder（本） .addConnectionCallbacks（本） .addOnConnectionFailedListener（本） .addApi（LocationServices.API） 。建立（）; } @覆盖 公共无效onConnected（包捆）抛出SecurityException异常 { Toast.makeText（这一点，连接，Toast.LENGTH_SHORT）.show（）; //从系统服务LOCATION_SERVICE获取的LocationManager对象 的LocationManager的LocationManager =（的LocationManager）getSystemService（Context.LOCATION_SERVICE）; //创建一个标准的对象来检索提供商 标准标准=新标准（）; //获取最佳供应商的名称 字符串提供商= locationManager.getBestProvider（标准，真正的）; //获取当前位置 位置myLocation = locationManager.getLastKnownLocation（供应商）; //获取当前位置的纬度 双纬度= myLocation.getLatitude（）; //获取当前位置的经度 双经度= myLocation.getLongitude（）; //创建一个经纬度对象的当前位置 的latLng =新的经纬度（纬度，经度）; //mGoogleMap.clear（）; //的latLng =新经纬度（mLastLocation.getLatitude（），mLastLocation.getLongitude（））; 的MarkerOptions的MarkerOptions =新的MarkerOptions（）; markerOptions.position（的latLng）; markerOptions.title（当前位置）; markerOptions.icon（BitmapDescriptorFactory.defaultMarker（BitmapDescriptorFactory.HUE_RED））; 标记M = mGoogleMap.addMarker（的MarkerOptions）; m.showInfoWindow（）; mGoogleMap.moveCamera（CameraUpdateFactory.newLatLng（的latLng））; mGoogleMap.animateCamera（CameraUpdateFactory.zoomTo（11））; Toast.makeText（这一点，触摸红色标记，以查看该医院的详细信息，Toast.LENGTH_LONG）.show（）; } @覆盖 公共无效onConnectionSuspended（int i）以{ Toast.makeText（这一点，onConnectionSuspended，Toast.LENGTH_SHORT）.show（）; } @覆盖 公共无效onConnectionFailed（ConnectionResult connectionResult）{ Toast.makeText（这一点，onConnectionFailed，Toast.LENGTH_SHORT）.show（）; } @覆盖 公共无效onLocationChanged（地点）{ } 公众的StringBuilder sbMethod（）抛出SecurityException异常 { 的LocationManager的LocationManager =（的LocationManager）getSystemService（Context.LOCATION_SERVICE）; 标准标准=新标准（）; 字符串提供商= locationManager.getBestProvider（标准，真正的）; 位置myLocation = locationManager.getLastKnownLocation（供应商）; mLatitude = myLocation.getLatitude（）; mLongitude = myLocation.getLongitude（）; StringBuilder的SB =新的StringBuilder（https://maps.googleapis.com/maps/api/place/nearbysearch/json？）; sb.append（位置=+ mLatitude +，+ mLongitude）; sb.append（与＆amp;半径= 20000）; sb.append（与＆amp;类型=+号医院|医生）; sb.append（与＆amp;传感器=真正的）; sb.append（与＆amp;关键= ***********************）; Log.d（地图，URL：+ sb.toString（））; 返回SB; } 私有类PlacesTask扩展的AsyncTask＆LT;字符串，整数，字符串＆GT; { 字符串数据= NULL;这个对象//通过调用执行（）方法@覆盖保护字符串doInBackground（字符串... URL）{ 尝试{ 数据= downloadUrl（URL [0]）; }赶上（例外五）{ Log.d（后台任务，e.toString（））; } 返回的数据;}// doInBackground完全执行（后执行）方法@覆盖保护无效onPostExecute（字符串结果）{ ParserTask parserTask =新ParserTask（）; //开始解析JSON格式的谷歌的地方 //调用的doInBackground（）之类ParserTask的方法 parserTask.execute（结果）;}}私人字符串downloadUrl（字符串strUrl）抛出IOException异常{ 字符串数据=; InputStream中的IStream = NULL; HttpURLConnection类的URLConnection = NULL; 尝试{ 网址URL =新的URL（strUrl）; //创建一个HTTP连接使用网址进行沟通 URLConnection的=（HttpURLConnection类）url.openConnection（）; //连接给url urlConnection.connect（）; // URL从读取数据 的IStream = urlConnection.getInputStream（）; BR的BufferedReader =新的BufferedReader（新的InputStreamReader（的IStream））; StringBuffer的SB =新的StringBuffer（）; 串线=; 而（（行= br.readLine（））！= NULL）{ sb.append（线）; } 数据= sb.toString（）; br.close（）; }赶上（例外五）{ Log.d（异常，e.toString（））; } {最后 iStream.close（）; urlConnection.disconnect（）; } 返回的数据;}私有类ParserTask扩展的AsyncTask＆LT;字符串，整数，列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;＆GT; {的JSONObject jObject;这个对象//通过调用执行（）方法@覆盖保护列表与LT; HashMap的＆LT;字符串，字符串＆GT;＆GT; doInBackground（字符串... jsonData）{ 清单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;地方= NULL; Place_JSON placeJson =新Place_JSON（）; 尝试{ jObject =新的JSONObject（jsonData [0]）; 地方= placeJson.parse（jObject）; }赶上（例外五）{ Log.d（异常，e.toString（））; } 回到地方;}// doInBackground完全执行（后执行）方法@覆盖保护无效onPostExecute（列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;名单）{ Log.d（地图，列表的大小：+则为list.size（））; //清除所有现有的标记; //mGoogleMap.clear（）; 的for（int i = 0; I＆LT;则为list.size（）;我++）{ //创建一个标志 的MarkerOptions的MarkerOptions =新的MarkerOptions（）; //充分利用地方名单的地方 HashMap的＆LT;字符串，字符串＆GT; hmPlace = list.get（ⅰ）; //获取地方纬度 双纬度= Double.parseDouble（hmPlace.get（纬度））; //获取地方的经度 双LNG = Double.parseDouble（hmPlace.get（LNG））; //获取名称 字符串名称= hmPlace.get（PLACE_NAME）; Log.d（地图，地点+姓名）; //获取附近 附近的String = hmPlace.get（附近）; 的latLng =新的经纬度（纬度，经度）; //设置对标记的位置 markerOptions.position（的latLng）; markerOptions.title（名称+：+附近）; markerOptions.icon（BitmapDescriptorFactory.defaultMarker（BitmapDescriptorFactory.HUE_MAGENTA））; //放置一个标记上触摸的位置 标记M = mGoogleMap.addMarker（的MarkerOptions）; } } } 公共类Place_JSON {/ ** *接收一个JSONObject并返回一个列表 * /公开名单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;解析（JSONObject的jObject）{ JSONArray jPlaces = NULL; 尝试{ / **获取所有元素的'地方'数组中* / jPlaces = jObject.getJSONArray（结果）; }赶上（JSONException E）{ e.printStackTrace（）; } / **调用getPlaces和JSON对象的数组 *每个JSON对象重新present的地方 * / 返回getPlaces（jPlaces）;}私人列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; getPlaces（JSONArray jPlaces）{ INT placesCount = jPlaces.length（）; 清单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; placesList =新的ArrayList＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;（）; HashMap的＆LT;字符串，字符串＆GT;地方= NULL; / **以每一个地方，解析并添加到列表对象* / 的for（int i = 0; I＆LT; placesCount;我++）{ 尝试{ / **调用getPlace与地方JSON对象解析地方* / 地方= getPlace（（JSONObject的）jPlaces.get（一））; placesList.add（地方）; }赶上（JSONException E）{ e.printStackTrace（）; } } 返回placesList;}/ ** *解析广场JSON对象 * /私人的HashMap＆LT;字符串，字符串＆GT; getPlace（JSONObject的jPlace）{ HashMap的＆LT;字符串，字符串＆GT;地方=新的HashMap＆LT;字符串，字符串＆GT;（）; 字符串地名=-NA-; 附近的String =-NA-; 串纬度=; 字符串的经度=; String引用=; 尝试{ //提取地名，如果有的话 如果（！jPlace.isNull（名字））{ 地名= jPlace.getString（名称）; } //提取广场气象台，如果可用 如果（！jPlace.isNull（附近））{ 附近= jPlace.getString（附近）; } 纬度= jPlace.getJSONObject（几何）getJSONObject（位置）的getString（纬度）。; 经度= jPlace.getJSONObject（几何）getJSONObject（位置）的getString（LNG）。; 基准= jPlace.getString（参考）; place.put（PLACE_NAME，地名）; place.put（附近，附近）; place.put（纬度，纬度）; place.put（LNG，经度）; place.put（参考，参考）; }赶上（JSONException E）{ e.printStackTrace（）; } 回到地方;}} 解决方案
首先，要连接到GooglePlayServices，但从未实际使用GooglePlayServices的位置。
而不是这样的：
位置myLocation = locationManager.getLastKnownLocation（供应商）; 您可能想做到这一点：
位置mLastLocation = LocationServices.FusedLocationApi.getLastLocation（ mGoogleApiClient）; 
然而，这些方法总是有返回null的机会，所以总是在上述方法的结果的空检查。你缺乏这个位置对象的空支票之前调用 mLatitude = myLocation.getLatitude（）; 是什么导致你的NullPointerException
不过，我也建议不要叫 getLastLocation（）可言，因而具有较高的倾向返回null。它也不会要求一个新的位置，因此，即使你得到一个位置返回，也可能是很老了，不能反映设备的当前位置。这是更好地注册一个监听器，你先去onLocationChanged（）回调后，即使你只是注销。
看起来你基本上要结合这个答案并的这个答案。
我基本上只是这样做，也清理了code位。
下面是整个类code：
进口android.location.Location;进口android.os.AsyncTask;进口android.os.Bundle;进口android.support.v7.app.AppCompatActivity;进口android.util.Log;进口com.google.android.gms.common.ConnectionResult;进口com.google.android.gms.common.api.GoogleApiClient;进口com.google.android.gms.location.LocationListener;进口com.google.android.gms.location.LocationRequest;进口com.google.android.gms.location.LocationServices;进口com.google.android.gms.maps.CameraUpdateFactory;进口com.google.android.gms.maps.GoogleMap;进口com.google.android.gms.maps.OnMa preadyCallback;进口com.google.android.gms.maps.SupportMapFragment;进口com.google.android.gms.maps.model.BitmapDescriptorFactory;进口com.google.android.gms.maps.model.LatLng;进口com.google.android.gms.maps.model.Marker;进口com.google.android.gms.maps.model.MarkerOptions;进口org.json.JSONArray;进口org.json.JSONException;进口org.json.JSONObject;进口java.io.BufferedReader中;进口java.io.IOException异常;进口的java.io.InputStream;进口java.io.InputStreamReader中;进口java.net.HttpURLConnection中;进口的java.net.URL;进口的java.util.ArrayList;进口的java.util.HashMap;进口的java.util.List;公共类MapsActivity2扩展AppCompatActivity 实现OnMa preadyCallback， GoogleApiClient.ConnectionCallbacks， GoogleApiClient.OnConnectionFailedListener， LocationListener的{ GoogleMap的mGoogleMap; SupportMapFragment mapFrag; LocationRequest mLocationRequest; GoogleApiClient mGoogleApiClient; 位置mLastLocation; 标记mCurrLocationMarker; 布尔firstRun =真; @覆盖 保护无效的onCreate（捆绑savedInstanceState） { super.onCreate（savedInstanceState）; 的setContentView（R.layout.activity_main）; mapFrag =（SupportMapFragment）getSupportFragmentManager（）findFragmentById（R.id.map）。 mapFrag.getMapAsync（本）; } @覆盖 公共无效的onPause（）{ super.onPause（）; //停止位置更新时的活动不再有效 如果（mGoogleApiClient！= NULL）{ LocationServices.FusedLocationApi.removeLocationUpdates（mGoogleApiClient，这一点）; } } @覆盖 公共无效onMa pready（GoogleMap的GoogleMap的） { mGoogleMap = GoogleMap的; mGoogleMap.setMyLocationEnabled（真）; mGoogleMap.setMapType（GoogleMap.MAP_TYPE_HYBRID）; //初始化谷歌播放服务 buildGoogleApiClient（）; mGoogleApiClient.connect（）; } 公众的StringBuilder sbMethod（位置currentLocation）{ //当前位置 双mLatitude = currentLocation.getLatitude（）; 双mLongitude = currentLocation.getLongitude（）; StringBuilder的SB =新的StringBuilder（https://maps.googleapis.com/maps/api/place/nearbysearch/json？）; sb.append（位置=+ mLatitude +，+ mLongitude）; sb.append（与＆amp;半径= 5000）; sb.append（与＆amp;类型=+餐厅）; sb.append（与＆amp;传感器=真正的）; sb.append（与＆amp;关键= AIza ********）; Log.d（地图，＆LT;＆GT;＆LT;＆GT; API：+ sb.toString（））; 返回SB; } 保护同步无效buildGoogleApiClient（）{ mGoogleApiClient =新GoogleApiClient.Builder（本） .addConnectionCallbacks（本） .addOnConnectionFailedListener（本） .addApi（LocationServices.API） 。建立（）; } @覆盖 公共无效onConnected（束束）{ mLocationRequest =新LocationRequest（）; mLocationRequest.setInterval（1000）; mLocationRequest.setFastestInterval（1000）; mLocationRequest.setPriority（LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY）; LocationServices.FusedLocationApi.requestLocationUpdates（mGoogleApiClient，mLocationRequest，这一点）; } @覆盖 公共无效onConnectionSuspended（int i）以{} @覆盖 公共无效onConnectionFailed（ConnectionResult connectionResult）{} @覆盖 公共无效onLocationChanged（地点） { mLastLocation =位置; 如果（mCurrLocationMarker！= NULL）{ mCurrLocationMarker.remove（）; } //将当前的位置标记 经纬度的latLng =新的经纬度（location.getLatitude（），location.getLongitude（））; 的MarkerOptions的MarkerOptions =新的MarkerOptions（）; markerOptions.position（的latLng）; markerOptions.title（当前位置）; markerOptions.icon（BitmapDescriptorFactory.defaultMarker（BitmapDescriptorFactory.HUE_MAGENTA））; mCurrLocationMarker = mGoogleMap.addMarker（的MarkerOptions）; //移动地图相机 mGoogleMap.moveCamera（CameraUpdateFactory.newLatLng（的latLng））; mGoogleMap.animateCamera（CameraUpdateFactory.zoomTo（11））; //查询与地方的当前位置 StringBuilder的sbValue =新的StringBuilder（sbMethod（位置））; PlacesTask placesTask =新PlacesTask（）; placesTask.execute（sbValue.toString（））; 如果（mGoogleApiClient！= NULL）{ LocationServices.FusedLocationApi.removeLocationUpdates（mGoogleApiClient，这一点）; } } 私有类PlacesTask扩展的AsyncTask＆LT;字符串，整数，字符串＆GT; { 字符串数据= NULL; 这个对象//通过调用执行（）方法 @覆盖 保护字符串doInBackground（字符串... URL）{ 尝试{ 数据= downloadUrl（URL [0]）; }赶上（例外五）{ Log.d（后台任务，e.toString（））; } 返回的数据; } // doInBackground完全执行（后执行）方法 @覆盖 保护无效onPostExecute（字符串结果）{ Log.d（结果，＆所述;＆GT;＆下;＆GT;结果：+导致）; ParserTask parserTask =新ParserTask（）; //开始解析JSON格式的谷歌的地方 //调用的doInBackground（）之类ParserTask的方法 parserTask.execute（结果）; } } 私人字符串downloadUrl（字符串strUrl）抛出IOException异常 { 字符串数据=; InputStream中的IStream = NULL; HttpURLConnection类的URLConnection = NULL; 尝试{ 网址URL =新的URL（strUrl）; //创建一个HTTP连接使用网址进行沟通 URLConnection的=（HttpURLConnection类）url.openConnection（）; //连接给url urlConnection.connect（）; // URL从读取数据 的IStream = urlConnection.getInputStream（）; BR的BufferedReader =新的BufferedReader（新的InputStreamReader（的IStream））; StringBuffer的SB =新的StringBuffer（）; 串线=; 而（（行= br.readLine（））！= NULL）{ sb.append（线）; } 数据= sb.toString（）; br.close（）; }赶上（例外五）{ Log.d（异常，e.toString（））; } {最后 iStream.close（）; urlConnection.disconnect（）; } 返回的数据; } 私有类ParserTask扩展的AsyncTask＆LT;字符串，整数，列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;＆GT; { 的JSONObject jObject; 这个对象//通过调用执行（）方法 @覆盖 保护列表与LT; HashMap的＆LT;字符串，字符串＆GT;＆GT; doInBackground（字符串... jsonData）{ 清单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;地方= NULL; Place_JSON placeJson =新Place_JSON（）; 尝试{ jObject =新的JSONObject（jsonData [0]）; 地方= placeJson.parse（jObject）; }赶上（例外五）{ Log.d（异常，e.toString（））; } 回到地方; } // doInBackground完全执行（后执行）方法 @覆盖 保护无效onPostExecute（列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;名单）{ Log.d（地图，列表的大小：+则为list.size（））; //清除所有现有的标记; 如果（！firstRun）{ mGoogleMap.clear（）; } firstRun = FALSE; 的for（int i = 0; I＆LT;则为list.size（）;我++）{ //创建一个标志 的MarkerOptions的MarkerOptions =新的MarkerOptions（）; //充分利用地方名单的地方 HashMap的＆LT;字符串，字符串＆GT; hmPlace = list.get（ⅰ）; //获取地方纬度 双纬度= Double.parseDouble（hmPlace.get（纬度））; //获取地方的经度 双LNG = Double.parseDouble（hmPlace.get（LNG））; //获取名称 字符串名称= hmPlace.get（PLACE_NAME）; Log.d（地图，地点+姓名）; //获取附近 附近的String = hmPlace.get（附近）; 经纬度的latLng =新的经纬度（纬度，经度）; //设置对标记的位置 markerOptions.position（的latLng）; markerOptions.title（名称+：+附近）; markerOptions.icon（BitmapDescriptorFactory.defaultMarker（BitmapDescriptorFactory.HUE_MAGENTA））; //放置一个标记上触摸的位置 标记M = mGoogleMap.addMarker（的MarkerOptions）; } } } 公共类Place_JSON { / ** *接收一个JSONObject并返回一个列表 * / 公开名单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;解析（JSONObject的jObject）{ JSONArray jPlaces = NULL; 尝试{ / **获取所有元素的'地方'数组中* / jPlaces = jObject.getJSONArray（结果）; }赶上（JSONException E）{ e.printStackTrace（）; } / **调用getPlaces和JSON对象的数组 *每个JSON对象重新present的地方 * / 返回getPlaces（jPlaces）; } 私人列表＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; getPlaces（JSONArray jPlaces）{ INT placesCount = jPlaces.length（）; 清单＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; placesList =新的ArrayList＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;（）; HashMap的＆LT;字符串，字符串＆GT;地方= NULL; / **以每一个地方，解析并添加到列表对象* / 的for（int i = 0; I＆LT; placesCount;我++）{ 尝试{ / **调用getPlace与地方JSON对象解析地方* / 地方= getPlace（（JSONObject的）jPlaces.get（一））; placesList.add（地方）; }赶上（JSONException E）{ e.printStackTrace（）; } } 返回placesList; } / ** *解析广场JSON对象 * / 私人的HashMap＆LT;字符串，字符串＆GT; getPlace（JSONObject的jPlace） { HashMap的＆LT;字符串，字符串＆GT;地方=新的HashMap＆LT;字符串，字符串＆GT;（）; 字符串地名=-NA-; 附近的String =-NA-; 串纬度=; 字符串的经度=; String引用=; 尝试{ //提取地名，如果有的话 如果（！jPlace.isNull（名字））{ 地名= jPlace.getString（名称）; } //提取广场气象台，如果可用 如果（！jPlace.isNull（附近））{ 附近= jPlace.getString（附近）; } 纬度= jPlace.getJSONObject（几何）getJSONObject（位置）的getString（纬度）。; 经度= jPlace.getJSONObject（几何）getJSONObject（位置）的getString（LNG）。; 基准= jPlace.getString（参考）; place.put（PLACE_NAME，地名）; place.put（附近，附近）; place.put（纬度，纬度）; place.put（LNG，经度）; place.put（参考，参考）; }赶上（JSONException E）{ e.printStackTrace（）; } 回到地方; } }} 结果：
I am trying to limit the place search type to hospital using google places api web services but unable to achieve it.
Logcat
java.lang.NullPointerException at com.ediode.graphics3d.ClinicFragment.sbMethod(ClinicFragment.java:174) at com.ediode.graphics3d.ClinicFragment.onMapReady(ClinicFragment.java:95)
MainActivity
public class ClinicFragment extends AppCompatActivity implements
GoogleApiClient.ConnectionCallbacks,GoogleApiClient.OnConnectionFailedListener,
LocationListener,
OnMapReadyCallback
{
private GoogleMap mGoogleMap;
SupportMapFragment mapFrag;
LocationRequest mLocationRequest;
GoogleApiClient mGoogleApiClient;
LatLng latLng;
double mLatitude=0;
double mLongitude=0;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.clinic_fragment);
mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFrag.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap)
{
mGoogleMap = googleMap;
mGoogleMap.setMyLocationEnabled(true);
buildGoogleApiClient();
mGoogleApiClient.connect();
StringBuilder sbValue = new StringBuilder(sbMethod());
PlacesTask placesTask = new PlacesTask();
placesTask.execute(sbValue.toString());
}
@Override
public void onPause()
{
super.onPause();
//Unregister for location callbacks:
if (mGoogleApiClient != null)
{
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
protected synchronized void buildGoogleApiClient()
{
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
@Override
public void onConnected(Bundle bundle) throws SecurityException
{
Toast.makeText(this,"Connected",Toast.LENGTH_SHORT).show();
// Get LocationManager object from System Service LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Create a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Get the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Get Current Location
Location myLocation = locationManager.getLastKnownLocation(provider);
// Get latitude of the current location
double latitude = myLocation.getLatitude();
// Get longitude of the current location
double longitude = myLocation.getLongitude();
// Create a LatLng object for the current location
latLng = new LatLng(latitude, longitude);
//mGoogleMap.clear();
//latLng = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
Marker m = mGoogleMap.addMarker(markerOptions);
m.showInfoWindow();
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(11));
Toast.makeText(this,"Touch the Pink Markers to View the Details of that Hospital",Toast.LENGTH_LONG).show();
}
@Override
public void onConnectionSuspended(int i) {
Toast.makeText(this,"onConnectionSuspended",Toast.LENGTH_SHORT).show();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Toast.makeText(this,"onConnectionFailed",Toast.LENGTH_SHORT).show();
}
@Override
public void onLocationChanged(Location location) {
}
public StringBuilder sbMethod() throws SecurityException
{
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String provider = locationManager.getBestProvider(criteria, true);
Location myLocation = locationManager.getLastKnownLocation(provider);
mLatitude=myLocation.getLatitude();
mLongitude=myLocation.getLongitude();
StringBuilder sb = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
sb.append("location=" + mLatitude + "," + mLongitude);
sb.append("&radius=20000");
sb.append("&types=" + "hospital|doctor");
sb.append("&sensor=true");
sb.append("&key=***********************");
Log.d("Map", "url: " + sb.toString());
return sb;
}
private class PlacesTask extends AsyncTask<String, Integer, String>
{
String data = null;
// Invoked by execute() method of this object
@Override
protected String doInBackground(String... url) {
try {
data = downloadUrl(url[0]);
} catch (Exception e) {
Log.d("Background Task", e.toString());
}
return data;
}
// Executed after the complete execution of doInBackground() method
@Override
protected void onPostExecute(String result) {
ParserTask parserTask = new ParserTask();
// Start parsing the Google places in JSON format
// Invokes the "doInBackground()" method of the class ParserTask
parserTask.execute(result);
}
}
private String downloadUrl(String strUrl) throws IOException
{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line);
}
data = sb.toString();
br.close();
} catch (Exception e) {
Log.d("Exception", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String, String>>> {
JSONObject jObject;
// Invoked by execute() method of this object
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {
List<HashMap<String, String>> places = null;
Place_JSON placeJson = new Place_JSON();
try {
jObject = new JSONObject(jsonData[0]);
places = placeJson.parse(jObject);
} catch (Exception e) {
Log.d("Exception", e.toString());
}
return places;
}
// Executed after the complete execution of doInBackground() method
@Override
protected void onPostExecute(List<HashMap<String, String>> list) {
Log.d("Map", "list size: " + list.size());
// Clears all the existing markers;
//mGoogleMap.clear();
for (int i = 0; i < list.size(); i++) {
// Creating a marker
MarkerOptions markerOptions = new MarkerOptions();
// Getting a place from the places list
HashMap<String, String> hmPlace = list.get(i);
// Getting latitude of the place
double lat = Double.parseDouble(hmPlace.get("lat"));
// Getting longitude of the place
double lng = Double.parseDouble(hmPlace.get("lng"));
// Getting name
String name = hmPlace.get("place_name");
Log.d("Map", "place: " + name);
// Getting vicinity
String vicinity = hmPlace.get("vicinity");
latLng = new LatLng(lat, lng);
// Setting the position for the marker
markerOptions.position(latLng);
markerOptions.title(name + " : " + vicinity);
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
// Placing a marker on the touched position
Marker m = mGoogleMap.addMarker(markerOptions);
}
}
}
public class Place_JSON {
/**
* Receives a JSONObject and returns a list
*/
public List<HashMap<String, String>> parse(JSONObject jObject) {
JSONArray jPlaces = null;
try {
/** Retrieves all the elements in the 'places' array */
jPlaces = jObject.getJSONArray("results");
} catch (JSONException e) {
e.printStackTrace();
}
/** Invoking getPlaces with the array of json object
* where each json object represent a place
*/
return getPlaces(jPlaces);
}
private List<HashMap<String, String>> getPlaces(JSONArray jPlaces) {
int placesCount = jPlaces.length();
List<HashMap<String, String>> placesList = new ArrayList<HashMap<String, String>>();
HashMap<String, String> place = null;
/** Taking each place, parses and adds to list object */
for (int i = 0; i < placesCount; i++) {
try {
/** Call getPlace with place JSON object to parse the place */
place = getPlace((JSONObject) jPlaces.get(i));
placesList.add(place);
} catch (JSONException e) {
e.printStackTrace();
}
}
return placesList;
}
/**
* Parsing the Place JSON object
*/
private HashMap<String, String> getPlace(JSONObject jPlace)
{
HashMap<String, String> place = new HashMap<String, String>();
String placeName = "-NA-";
String vicinity = "-NA-";
String latitude = "";
String longitude = "";
String reference = "";
try {
// Extracting Place name, if available
if (!jPlace.isNull("name")) {
placeName = jPlace.getString("name");
}
// Extracting Place Vicinity, if available
if (!jPlace.isNull("vicinity")) {
vicinity = jPlace.getString("vicinity");
}
latitude = jPlace.getJSONObject("geometry").getJSONObject("location").getString("lat");
longitude = jPlace.getJSONObject("geometry").getJSONObject("location").getString("lng");
reference = jPlace.getString("reference");
place.put("place_name", placeName);
place.put("vicinity", vicinity);
place.put("lat", latitude);
place.put("lng", longitude);
place.put("reference", reference);
} catch (JSONException e) {
e.printStackTrace();
}
return place;
}
}
解决方案
First of all, you're connecting to GooglePlayServices, but never actually using GooglePlayServices for the location.
Instead of this:
Location myLocation = locationManager.getLastKnownLocation(provider);
You probably wanted to do this:
Location mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
mGoogleApiClient);
However, these methods always have a chance of returning null, so always do a null check on the result of the above methods. Your lack of a null check on this location object before calling mLatitude=myLocation.getLatitude(); is what was causing your NullPointerException.
However, I would also advise against calling getLastLocation() at all, which has a high tendency to return null. It also does not request a new location, so even if you get a location returned, it could be very old, and not reflect the current location of the device. It's better to register a listener, even if you just unregister after you get the first onLocationChanged() callback.
It looks like you basically want to combine this answer and this answer.
I just basically did that, and also cleaned up the code a bit.
Here's the entire class code:
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
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.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.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class MapsActivity2 extends AppCompatActivity
implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
GoogleMap mGoogleMap;
SupportMapFragment mapFrag;
LocationRequest mLocationRequest;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
boolean firstRun = true;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFrag.getMapAsync(this);
}
@Override
public void onPause() {
super.onPause();
//stop location updates when Activity is no longer active
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@Override
public void onMapReady(GoogleMap googleMap)
{
mGoogleMap=googleMap;
mGoogleMap.setMyLocationEnabled(true);
mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
//Initialize Google Play Services
buildGoogleApiClient();
mGoogleApiClient.connect();
}
public StringBuilder sbMethod(Location currentLocation) {
//current location
double mLatitude = currentLocation.getLatitude();
double mLongitude = currentLocation.getLongitude();
StringBuilder sb = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
sb.append("location=" + mLatitude + "," + mLongitude);
sb.append("&radius=5000");
sb.append("&types=" + "restaurant");
sb.append("&sensor=true");
sb.append("&key=AIza********************");
Log.d("Map", "<><>api: " + sb.toString());
return sb;
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
@Override
public void onConnectionSuspended(int i) {}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {}
@Override
public void onLocationChanged(Location location)
{
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mGoogleMap.addMarker(markerOptions);
//move map camera
mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//query places with current location
StringBuilder sbValue = new StringBuilder(sbMethod(location));
PlacesTask placesTask = new PlacesTask();
placesTask.execute(sbValue.toString());
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
private class PlacesTask extends AsyncTask<String, Integer, String>
{
String data = null;
// Invoked by execute() method of this object
@Override
protected String doInBackground(String... url) {
try {
data = downloadUrl(url[0]);
} catch (Exception e) {
Log.d("Background Task", e.toString());
}
return data;
}
// Executed after the complete execution of doInBackground() method
@Override
protected void onPostExecute(String result) {
Log.d("result", "<><> result: " + result);
ParserTask parserTask = new ParserTask();
// Start parsing the Google places in JSON format
// Invokes the "doInBackground()" method of the class ParserTask
parserTask.execute(result);
}
}
private String downloadUrl(String strUrl) throws IOException
{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line);
}
data = sb.toString();
br.close();
} catch (Exception e) {
Log.d("Exception", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String, String>>> {
JSONObject jObject;
// Invoked by execute() method of this object
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {
List<HashMap<String, String>> places = null;
Place_JSON placeJson = new Place_JSON();
try {
jObject = new JSONObject(jsonData[0]);
places = placeJson.parse(jObject);
} catch (Exception e) {
Log.d("Exception", e.toString());
}
return places;
}
// Executed after the complete execution of doInBackground() method
@Override
protected void onPostExecute(List<HashMap<String, String>> list) {
Log.d("Map", "list size: " + list.size());
// Clears all the existing markers;
if (!firstRun) {
mGoogleMap.clear();
}
firstRun = false;
for (int i = 0; i < list.size(); i++) {
// Creating a marker
MarkerOptions markerOptions = new MarkerOptions();
// Getting a place from the places list
HashMap<String, String> hmPlace = list.get(i);
// Getting latitude of the place
double lat = Double.parseDouble(hmPlace.get("lat"));
// Getting longitude of the place
double lng = Double.parseDouble(hmPlace.get("lng"));
// Getting name
String name = hmPlace.get("place_name");
Log.d("Map", "place: " + name);
// Getting vicinity
String vicinity = hmPlace.get("vicinity");
LatLng latLng = new LatLng(lat, lng);
// Setting the position for the marker
markerOptions.position(latLng);
markerOptions.title(name + " : " + vicinity);
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
// Placing a marker on the touched position
Marker m = mGoogleMap.addMarker(markerOptions);
}
}
}
public class Place_JSON {
/**
* Receives a JSONObject and returns a list
*/
public List<HashMap<String, String>> parse(JSONObject jObject) {
JSONArray jPlaces = null;
try {
/** Retrieves all the elements in the 'places' array */
jPlaces = jObject.getJSONArray("results");
} catch (JSONException e) {
e.printStackTrace();
}
/** Invoking getPlaces with the array of json object
* where each json object represent a place
*/
return getPlaces(jPlaces);
}
private List<HashMap<String, String>> getPlaces(JSONArray jPlaces) {
int placesCount = jPlaces.length();
List<HashMap<String, String>> placesList = new ArrayList<HashMap<String, String>>();
HashMap<String, String> place = null;
/** Taking each place, parses and adds to list object */
for (int i = 0; i < placesCount; i++) {
try {
/** Call getPlace with place JSON object to parse the place */
place = getPlace((JSONObject) jPlaces.get(i));
placesList.add(place);
} catch (JSONException e) {
e.printStackTrace();
}
}
return placesList;
}
/**
* Parsing the Place JSON object
*/
private HashMap<String, String> getPlace(JSONObject jPlace)
{
HashMap<String, String> place = new HashMap<String, String>();
String placeName = "-NA-";
String vicinity = "-NA-";
String latitude = "";
String longitude = "";
String reference = "";
try {
// Extracting Place name, if available
if (!jPlace.isNull("name")) {
placeName = jPlace.getString("name");
}
// Extracting Place Vicinity, if available
if (!jPlace.isNull("vicinity")) {
vicinity = jPlace.getString("vicinity");
}
latitude = jPlace.getJSONObject("geometry").getJSONObject("location").getString("lat");
longitude = jPlace.getJSONObject("geometry").getJSONObject("location").getString("lng");
reference = jPlace.getString("reference");
place.put("place_name", placeName);
place.put("vicinity", vicinity);
place.put("lat", latitude);
place.put("lng", longitude);
place.put("reference", reference);
} catch (JSONException e) {
e.printStackTrace();
}
return place;
}
}
}
Result:
相关推荐
猜您喜欢
精彩图集
