使用谷歌Places API的Web服务为Android特定搜索附近的地方 [英] Search specific nearby places using google places api web services for android
本文介绍了使用谷歌Places API的Web服务为Android特定搜索附近的地方的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
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。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:
这篇关于使用谷歌Places API的Web服务为Android特定搜索附近的地方的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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