我正在尝试通过单击保存按钮获取我的位置并将其存储在数据库。
问题：
当我尝试获取我的位置时，它向我显示空指针异常。
谁能告诉我我的代码出了什么问题？
我的代码：
public class OthersFragment extends Fragment implements OnMapReadyCallback,GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener {
View view;
private GoogleMap mMap;
GoogleApiClient mGoogleApiClient;
Double latitude;
Double longitude;
String strplace;
public static OthersFragment newInstance() {
OthersFragment fragment = new OthersFragment();
return fragment;
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// mGoogleApiClient = new GoogleApiClient.Builder(getContext())
// .addApi(LocationServices.API)
// .addConnectionCallbacks(this)
// .addOnConnectionFailedListener(this)
// .build();
view = inflater.inflate(R.layout.fragment_other, null, false);
SupportMapFragment mapFragment = (SupportMapFragment) this.getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
return view;
}
@Override
public void onMapReady(GoogleMap googleMap) {
mGoogleApiClient = new GoogleApiClient.Builder(getContext())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
mMap.setMyLocationEnabled(true);
mMap.setOnMyLocationButtonClickListener(new GoogleMap.OnMyLocationButtonClickListener() {
@Override
public boolean onMyLocationButtonClick() {
Location mylocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
ShowPopUp(mylocation);
return true;
}
});
googleMap.getUiSettings().setZoomControlsEnabled(true);
googleMap.getUiSettings().setAllGesturesEnabled(true);
}
private void ShowPopUp(final Location mylocation) {
int popupWidth = 300;
int popupHeight = 150;
// Inflate the popup_layout.xml
LinearLayout viewGroup = (LinearLayout)view.findViewById(R.id.popup);
LayoutInflater layoutInflater = (LayoutInflater)getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = layoutInflater.inflate(R.layout.popup, viewGroup);
// Creating the PopupWindow
final PopupWindow popup = new PopupWindow();
popup.setContentView(layout);
popup.setWidth(popupWidth);
popup.setHeight(popupHeight);
popup.setFocusable(true);
// Some offset to align the popup a bit to the right, and a bit down, relative to button's position.
int OFFSET_X = 30;
int OFFSET_Y = 30;
// Clear the default translucent background
popup.setBackgroundDrawable(new BitmapDrawable());
// Displaying the popup at the specified location, + offsets.
popup.showAtLocation(layout, Gravity.NO_GRAVITY, + OFFSET_X, OFFSET_Y);
// Getting a reference to Close button, and close the popup when clicked.
Button save = (Button) layout.findViewById(R.id.save);
Button retrieve = (Button) layout.findViewById(R.id.retrieve);
final EditText place = (EditText)layout.findViewById(R.id.place);
final EditText phone = (EditText)layout.findViewById(R.id.phone);
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String action = "save";
String strplace = place.getText().toString();
String strphone = phone.getText().toString();
new storePoints().execute(strplace,String.valueOf(mylocation.getLatitude()), String.valueOf(mylocation.getLongitude()), action);
popup.dismiss();
}
});
retrieve.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String action = "retrieve";
strplace = place.getText().toString();
String strphone = phone.getText().toString();
new retrievePoints().execute(strplace, action);
popup.dismiss();
}
});
}
@Override
public void onConnected(Bundle bundle) {
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
private class storePoints extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
try {
String place = (String) params[0];
// String phone = (String) params[1];
String latitude = (String) params[1];
String longitude = (String) params[2];
String action = (String) params[3];
String link = "http://192.168.0.152/prestige/saveCoord.php";
// String link = "http://10.0.2.2/coordinates/coord.php";
String data = URLEncoder.encode("station_name", "UTF-8") + "=" + URLEncoder.encode(place, "UTF-8");
// data += "&" + URLEncoder.encode("phone", "UTF-8") + "=" + URLEncoder.encode(phone, "UTF-8");
data += "&" + URLEncoder.encode("latitude", "UTF-8") + "=" + URLEncoder.encode(latitude, "UTF-8");
data += "&" + URLEncoder.encode("longitude", "UTF-8") + "=" + URLEncoder.encode(longitude, "UTF-8");
URL url = new URL(link);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
wr.flush();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
// Read Server Response
while ((line = reader.readLine()) != null) {
sb.append(line);
break;
}
return sb.toString();
} catch (Exception e) {
return new String("Exception: " + e.getMessage());
}
}
@Override
protected void onPostExecute(String result) {
Toast.makeText(OthersFragment.this.getContext(), result, Toast.LENGTH_LONG).show();
}
}
private class retrievePoints extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... params) {
try {
String place = (String) params[0];
String phone = (String) params[1];
String link = "http://192.168.0.152/prestige/retCoord.php";
// String link = "http://10.0.2.2/coordinates/retCoord.php";
String data = URLEncoder.encode("station_name", "UTF-8") + "=" + URLEncoder.encode(place, "UTF-8");
data += "&" + URLEncoder.encode("phone", "UTF-8") + "=" + URLEncoder.encode(phone, "UTF-8");
URL url = new URL(link);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
wr.flush();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
// Read Server Response
while ((line = reader.readLine()) != null) {
sb.append(line);
break;
}
return sb.toString();
} catch (Exception e) {
return new String("Exception: " + e.getMessage());
}
}
@Override
protected void onPostExecute(String result) {
// Toast.makeText(MainActivity.this,result,Toast.LENGTH_LONG).show();
try {
mMap.clear(); // clear all the markers on the map.
JSONArray loc_arr = new JSONArray(result);
for (int i = 0; i < loc_arr.length(); i++){
JSONObject loc_obj = loc_arr.getJSONObject(i);
Double latitude = Double.valueOf((loc_obj.getString("latitude")));
Double longitude = Double.valueOf((loc_obj.getString("longitude")));
String place = loc_obj.getString("station_name");
// Toast.makeText(MainActivity.this, "latitude: "+latitude +"t Longitude: " + longitude+"t Place: "+place, Toast.LENGTH_SHORT).show();
Marker marker= mMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("Place: "+place).snippet("Latitude: " +latitude+",Longitude: "+longitude));
marker.showInfoWindow();
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude,longitude),28));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
错误日志：
06-20 12:30:42.740 6682-6682/com.example.barbegambino.apslocate E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.barbegambino.apslocate, PID: 6682
java.lang.NullPointerException
at com.example.barbegambino.apslocate.fragments.OthersFragment$2.onClick(OthersFragment.java:166)
at android.view.View.performClick(View.java:4463)
at android.view.View$PerformClick.run(View.java:18789)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5299)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:829)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:645)
at dalvik.system.NativeStart.main(Native Method)
例如，尝试获取最后已知的位置，如下所示，
public class MapExample extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
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();
}
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@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);
}
}
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);
}
else{
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (mLastLocation != null) {
// work with your last location.
} else {
Toast.makeText(this, R.string.no_location, Toast.LENGTH_LONG).show();
}
}
}
@Override
public void onConnectionSuspended(int i) {
}
@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 = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@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.
}
}
}
我添加了这个，它对我有用。
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_entry, null, false);
//added
if (!isGooglePlayServicesAvailable()) {
Toast.makeText(getContext(), "Google Play Services is not available", Toast.LENGTH_LONG).show();
getActivity().finish();
}
mGoogleApiClient = new GoogleApiClient.Builder(getContext())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
SupportMapFragment mapFragment = (SupportMapFragment) this.getChildFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
return view;
}
这也是我添加的
@Override
public void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
@Override
public void onStop() {
super.onStop();
mGoogleApiClient.disconnect();
}
private boolean isGooglePlayServicesAvailable() {
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getContext());
if (ConnectionResult.SUCCESS == status) {
return true;
} else {
GooglePlayServicesUtil.getErrorDialog(status, getActivity(), 0).show();
Toast.makeText(getContext(), "Google Play Services is not Available", Toast.LENGTH_LONG).show();
return false;
}
}