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我正在實施顯示最近餐館的應用程序。我想要有兩個活動，一個在地圖中顯示餐廳，另一個在ListView中顯示。將Google Places商品添加到ListView中
這是檢索數據添加標記的代碼。
public class GetNearbyPlacesData extends AsyncTask<Object, String, String> {
String googlePlacesData;
GoogleMap mMap;
String url;
@Override
protected String doInBackground(Object... params) {
try {
Log.d("GetNearbyPlacesData", "doInBackground entered");
mMap = (GoogleMap) params[0];
url = (String) params[1];
DownloadUrl downloadUrl = new DownloadUrl();
googlePlacesData = downloadUrl.readUrl(url);
Log.d("GooglePlaceData", googlePlacesData);
Log.d("GooglePlacesReadTask", "doInBackground Exit");
} catch (Exception e) {
Log.d("GooglePlacesReadTask", e.toString());
}
return googlePlacesData;
}
@Override
protected void onPostExecute(String result) {
Log.d("GooglePlacesReadTask", "onPostExecute Entered");
List<HashMap<String, String>> nearbyPlacesList = null;
DataParser dataParser = new DataParser();
nearbyPlacesList = dataParser.parse(result);
Log.d("List of restaurants",nearbyPlacesList.toString());
ShowNearbyPlaces(nearbyPlacesList);
Log.d("GooglePlacesReadTask", "onPostExecute Exit");
}
private void ShowNearbyPlaces(List<HashMap<String, String>> nearbyPlacesList) {
for (int i = 0; i < nearbyPlacesList.size(); i++) {
Log.d("onPostExecute","Entered into showing locations");
MarkerOptions markerOptions = new MarkerOptions();
HashMap<String, String> googlePlace = nearbyPlacesList.get(i);
double lat = Double.parseDouble(googlePlace.get("lat"));
double lng = Double.parseDouble(googlePlace.get("lng"));
String placeName = googlePlace.get("place_name");
String vicinity = googlePlace.get("vicinity");
LatLng latLng = new LatLng(lat, lng);
markerOptions.position(latLng);
markerOptions.title(placeName + " : " + vicinity);
mMap.addMarker(markerOptions);
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
}
}
}
該分析數據的代碼：
public class DataParser {
public List<HashMap<String, String>> parse(String jsonData) {
JSONArray jsonArray = null;
JSONObject jsonObject;
try {
Log.d("Places", "parse");
jsonObject = new JSONObject(jsonData);
jsonArray = jsonObject.getJSONArray("results");
} catch (JSONException e) {
Log.d("Places", "parse error");
e.printStackTrace();
}
return getPlaces(jsonArray);
}
private List<HashMap<String, String>> getPlaces(JSONArray jsonArray) {
int placesCount = jsonArray.length();
List<HashMap<String, String>> placesList = new ArrayList<>();
HashMap<String, String> placeMap = null;
Log.d("Places", "getPlaces");
for (int i = 0; i < placesCount; i++) {
try {
placeMap = getPlace((JSONObject) jsonArray.get(i));
placesList.add(placeMap);
Log.d("Places", "Adding places");
} catch (JSONException e) {
Log.d("Places", "Error in Adding places");
e.printStackTrace();
}
}
return placesList;
}
private HashMap<String, String> getPlace(JSONObject googlePlaceJson) {
HashMap<String, String> googlePlaceMap = new HashMap<String, String>();
String placeName = "-NA-";
String vicinity = "-NA-";
String latitude = "";
String longitude = "";
String reference = "";
Log.d("getPlace", "Entered");
try {
if (!googlePlaceJson.isNull("name")) {
placeName = googlePlaceJson.getString("name");
}
if (!googlePlaceJson.isNull("vicinity")) {
vicinity = googlePlaceJson.getString("vicinity");
}
latitude = googlePlaceJson.getJSONObject("geometry").getJSONObject("location").getString("lat");
longitude = googlePlaceJson.getJSONObject("geometry").getJSONObject("location").getString("lng");
reference = googlePlaceJson.getString("reference");
googlePlaceMap.put("place_name", placeName);
googlePlaceMap.put("vicinity", vicinity);
googlePlaceMap.put("lat", latitude);
googlePlaceMap.put("lng", longitude);
googlePlaceMap.put("reference", reference);
Log.d("getPlace", "Putting Places");
} catch (JSONException e) {
Log.d("getPlace", "Error");
e.printStackTrace();
}
return googlePlaceMap;
}
}
這是HttpConnection的：
public class DownloadUrl {
public String readUrl(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();
Log.d("downloadUrl", data.toString());
br.close();
} catch (Exception e) {
Log.d("Exception", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
}
這就是我試圖做檢索回覆：
public class ListRestActivity extends AppCompatActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new GetNearbyPlacesData().execute();
}
}
編輯
新增的活動，獲取我的緯度和經度，構建我的網址：
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
double latitude;
double longitude;
private int PROXIMITY_RADIUS = 10000;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
//Check if Google Play Services Available or not
if (!CheckGooglePlayServices()) {
Log.d("onCreate", "Finishing test case since Google Play Services are not available");
finish();
}
else {
Log.d("onCreate","Google Play Services available.");
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
private boolean CheckGooglePlayServices() {
GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
int result = googleAPI.isGooglePlayServicesAvailable(this);
if(result != ConnectionResult.SUCCESS) {
if(googleAPI.isUserResolvableError(result)) {
googleAPI.getErrorDialog(this, result,
0).show();
}
return false;
}
return true;
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
String Restaurant = "restaurant";
mMap.clear();
String url = getUrl(latitude, longitude, Restaurant);
Object[] DataTransfer = new Object[2];
DataTransfer[0] = mMap;
DataTransfer[1] = url;
GetNearbyPlacesData getNearbyPlacesData = new GetNearbyPlacesData();
getNearbyPlacesData.execute(DataTransfer);
Toast.makeText(MapsActivity.this,"Nearby Restaurants", Toast.LENGTH_LONG).show();
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
private String getUrl(double latitude, double longitude, String nearbyPlace) {
//Place current location marker
latitude = 45.772;
longitude = 21.219;
StringBuilder googlePlacesUrl = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
googlePlacesUrl.append("location=" + latitude + "," + longitude);
googlePlacesUrl.append("&radius=" + PROXIMITY_RADIUS);
googlePlacesUrl.append("&type=" + nearbyPlace);
googlePlacesUrl.append("&sensor=true");
googlePlacesUrl.append("&key=" + "-");
Log.d("getUrl", googlePlacesUrl.toString());
return (googlePlacesUrl.toString());
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onLocationChanged(Location location) {
Log.d("onLocationChanged", "entered");
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
latitude = location.getLatitude();
longitude = location.getLongitude();
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 = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
Toast.makeText(MapsActivity.this,"Your Current Location", Toast.LENGTH_LONG).show();
Log.d("onLocationChanged", String.format("latitude:%.3f longitude:%.3f",latitude,longitude));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
Log.d("onLocationChanged", "Removing Location Updates");
}
Log.d("onLocationChanged", "Exit");
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission(){
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted. Do the
// contacts-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other permissions this app might request.
// You can add here other case statements according to your requirement.
}
}
}
logcat的：
1-16 16:18:12.101 4224-4224/com.upt.cti.nearbyrestaurant E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
at org.json.JSONTokener.nextValue(JSONTokener.java:94)
at org.json.JSONObject.<init>(JSONObject.java:154)
at org.json.JSONObject.<init>(JSONObject.java:171)
at com.upt.cti.nearbyrestaurant.DataParser.parse(DataParser.java:25)
at com.upt.cti.nearbyrestaurant.GetNearbyPlacesData.onPostExecute(GetNearbyPlacesData.java:46)
at com.upt.cti.nearbyrestaurant.GetNearbyPlacesData.onPostExecute(GetNearbyPlacesData.java:19)
at android.os.AsyncTask.finish(AsyncTask.java:631)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4963)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
我得到一個NullpointerException。這是不夠的？有人能幫助我嗎？
我們需要整個logcat的消息。請在這裏發帖，否則很難幫助你。 –
@AndreiT：我添加了LogCat – didi
嘗試調試應用程序並檢查結果json是否爲有效的json文件，因爲它似乎解析失敗。 –