NullPointerException:在 OnMapReady 方法中抛出

Question

开始运行我的谷歌地图项目，并在 日志猫 ->

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.example.sachiewerk.smart_healthcare.pharma2.onMapReady(pharma2.java:100)
at com.google.android.gms.maps.zzak.zza(Unknown Source)
at com.google.android.gms.maps.internal.zzaq.onTransact(Unknown Source)
at android.os.Binder.transact(Binder.java:504)
at fr.b(:com.google.android.gms.dynamite_dynamitemodulesb@12688021@12.6.88 (040306-197970725):20)
at com.google.android.gms.maps.internal.bg.a(:com.google.android.gms.dynamite_dynamitemodulesb@12688021@12.6.88 (040306-197970725):5)
at com.google.maps.api.android.lib6.impl.be.run(:com.google.android.gms.dynamite_dynamitemodulesb@12688021@12.6.88 (040306-197970725):5)
at android.os.Handler.handleCallback(Handler.java:836)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:203)
at android.app.ActivityThread.main(ActivityThread.java:6251)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)

该应用程序查找并显示附近的药房，此类在自定义信息窗口中显示附近药房详细信息的详细信息，例如(地址，电话号码，网站URI和价格评级(。

这是类 Java 代码

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.WindowManager;
import android.view.inputmethod.EditorInfo;
import android.widget.AdapterView;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.example.sachiewerk.smart_healthcare.models.PlaceInfo;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.GooglePlayServicesNotAvailableException;
import com.google.android.gms.common.GooglePlayServicesRepairableException;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.PendingResult;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.location.FusedLocationProviderClient;
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.location.places.AutocompletePrediction;
import com.google.android.gms.location.places.Place;
import com.google.android.gms.location.places.PlaceBuffer;
import com.google.android.gms.location.places.Places;
import com.google.android.gms.location.places.ui.PlacePicker;
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.LatLngBounds;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class pharma2 extends AppCompatActivity implements OnMapReadyCallback,
GoogleApiClient.OnConnectionFailedListener,
GoogleApiClient.ConnectionCallbacks,
LocationListener {
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
@Override
public void onMapReady(GoogleMap googleMap) {
Toast.makeText(this, "Map is Ready", Toast.LENGTH_SHORT).show();
Log.d(TAG, "onMapReady: map is ready..");
mMap = googleMap;
if (mLocationPermissionGranted) {
getDeviceLocation();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}


mMap.getUiSettings().setMyLocationButtonEnabled(false);
buildGoogleApiClient();
init();
}
/*
------------------------------------------------------------------------
*/
Button btnPharma = (Button) findViewById(R.id.btnPharma);
btnPharma.setOnClickListener(new View.OnClickListener(){
String search = "pharmacy";
@Override
public void onClick (View v){
mMap.clear();
String url = getUrl(latitude, longitude, search);
Object[] DataTransfer = new Object[2];
DataTransfer[0] = mMap;
DataTransfer[1] = url;
GetNearbyBanksData getNearbyPlacesData = new GetNearbyBanksData();
getNearbyPlacesData.execute(DataTransfer);
Toast.makeText(pharma2.this, "These are your Nearby Pharmacies! ",
Toast.LENGTH_LONG).show();
}
});
/*
------------------------------------------------------------------------
*/
}

private static final String TAG = "pharma2";
private static final String FINE_LOCATION = Manifest.permission.ACCESS_FINE_LOCATION;
private static final String COARSE_LOCATION = Manifest.permission.ACCESS_COARSE_LOCATION;
private static final int LOCATION_PERMISSION_REQUEST_CODE = 1234;
private static final float DEFAULT_ZOOM = 20f;
private static final int PLACE_PICKER_REQUEST = 1;
private static final LatLngBounds LAT_LNG_BOUNDS = new LatLngBounds(
new LatLng(-40, -168), new LatLng(71, 136));
//widgets
private AutoCompleteTextView mSearchText;
private ImageView mGps;
private ImageView mInfo;
private ImageView mPlacePicker;

//vars
private boolean mLocationPermissionGranted = false;
private GoogleMap mMap;
private FusedLocationProviderClient mFusedLocationProviderClient;
private PlaceAutocompleteAdapter mPlaceAutocompleteAdapter;
private GoogleApiClient mGoogleApiClient;
private PlaceInfo mPlace;
private Marker mMarker;
private Location mLastLocation;
LocationRequest mLocationRequest;
double latitude, longitude;
private int PROXIMITY_RADIUS = 10000;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hosp2);
mSearchText = (AutoCompleteTextView) findViewById(R.id.input_search);
mGps = (ImageView) findViewById(R.id.ic_gps);
mInfo = (ImageView) findViewById(R.id.place_info);
mPlacePicker = (ImageView) findViewById(R.id.place_picker);

getLocationPermission();
}

private void init() {
Log.d(TAG, "init: initializing");
mGoogleApiClient = new GoogleApiClient
.Builder(this)
.addApi(Places.GEO_DATA_API)
.addApi(Places.PLACE_DETECTION_API)
.enableAutoManage(this, this)
.build();
mSearchText.setOnItemClickListener(mAutocompleteClickListener);

mPlaceAutocompleteAdapter = new PlaceAutocompleteAdapter(this, Places.getGeoDataClient(this, null),
LAT_LNG_BOUNDS, null);

mSearchText.setAdapter(mPlaceAutocompleteAdapter);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.CUPCAKE) {
mSearchText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
public boolean onEditorAction(TextView textView, int actionId, KeyEvent keyEvent) {
if (actionId == EditorInfo.IME_ACTION_SEARCH
|| actionId == EditorInfo.IME_ACTION_DONE
|| keyEvent.getAction() == KeyEvent.ACTION_DOWN
|| keyEvent.getAction() == KeyEvent.KEYCODE_ENTER) {
//execute our method for searching
geolocate();
}
return false;
}
});
}
mGps.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG, "onClick: clicked gps icon");
getDeviceLocation();
}
});
mInfo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG, "onClick: clicked place Info");
try {
if (mMarker.isInfoWindowShown()) {
mMarker.hideInfoWindow();
} else {
Log.d(TAG, "onClick: place info: " + mPlace.toString());
mMarker.showInfoWindow();
}
} catch (NullPointerException e) {
Log.e(TAG, "onClick: NullPointerException: " + e.getMessage());
}
}
});
mPlacePicker.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
PlacePicker.IntentBuilder builder = new PlacePicker.IntentBuilder();
try {
startActivityForResult(builder.build(pharma2.this), PLACE_PICKER_REQUEST);
} catch (GooglePlayServicesRepairableException e) {
Log.e(TAG, "onClick: GooglePlayServicesRepairableException: " + e.getMessage());
} catch (GooglePlayServicesNotAvailableException e) {
Log.e(TAG, "onClick: GooglePlayServicesNotAvailableException: " + e.getMessage());
}
}
});
hideSoftKeyboard();

}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == PLACE_PICKER_REQUEST) {
if (resultCode == RESULT_OK) {
Place place = PlacePicker.getPlace(this, data);
PendingResult<PlaceBuffer> placeResult = Places.GeoDataApi
.getPlaceById(mGoogleApiClient, place.getId());
placeResult.setResultCallback(mUpdatePlaceDetailsCallback);
}
}
}

private void geolocate() {
Log.d(TAG, "geolocate: geolocating");
String searchString = mSearchText.getText().toString();
Geocoder geocoder = new Geocoder(pharma2.this);
List<Address> list = new ArrayList<>();
try {
list = geocoder.getFromLocationName(searchString, 2);
} catch (IOException e) {
Log.d(TAG, "geolocate: IOException: " + e.getMessage());
}
if (list.size() > 0) {
Address address = list.get(0);
Log.d(TAG, "geolocate: found a location: " + address.toString());
//Toast.makeText(this, "", Toast.LENGTH_SHORT).show();
moveCamera(new LatLng(address.getLatitude(), address.getLongitude()), DEFAULT_ZOOM,
address.getAddressLine(0));
}
}


@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) {
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=" + "AIzaSyAvxiw4FVJzY-XGx9mW8fNde4bjvc8mlbo");
return (googlePlacesUrl.toString());
}

/*
------------------------------------------------------------------------
*/

private void getDeviceLocation() {
Log.d(TAG, "getDeviceLocation: getting device's current location");
mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
try {
if (mLocationPermissionGranted) {
Task location = mFusedLocationProviderClient.getLastLocation();
location.addOnCompleteListener(new OnCompleteListener() {
@Override
public void onComplete(@NonNull Task task) {
if (task.isSuccessful()) {
Log.d(TAG, "onComplete: found location");
Location currentLocation = (Location) task.getResult();
moveCamera(new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude()),
DEFAULT_ZOOM, "Your Device's Location");
} else {
Log.d(TAG, "onComplete: current location is null");
Toast.makeText(pharma2.this, "unable to get current location", Toast.LENGTH_SHORT).show();
}
}
});
}
} catch (SecurityException e) {
Log.e(TAG, "getDeviceLocation: SecurityException: " + e.getMessage());
}
}

private void moveCamera(LatLng latLng, float zoom, PlaceInfo placeInfo) {
Log.d(TAG, "moveCamera: moving the camera to: lat: " + latLng.latitude + ", lng: " + latLng.longitude);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoom));
mMap.clear();
mMap.setInfoWindowAdapter(new CustomInfoWindowAdapter(pharma2.this));
if (placeInfo != null) {
try {
String snippet = "Address: " + placeInfo.getAddress() + "n" +
"Phone Number: " + placeInfo.getPhoneNumber() + "n" +
"Website: " + placeInfo.getWebsiteUri() + "n" +
"Rating: " + placeInfo.getRating() + "n";
MarkerOptions options = new MarkerOptions()
.position(latLng)
.title(placeInfo.getName())
.snippet(snippet);
mMarker = mMap.addMarker(options);
} catch (NullPointerException e) {
Log.e(TAG, "moveCamera: NullPointerException: " + e.getMessage());
}
} else {
mMap.addMarker(new MarkerOptions().position(latLng));
}
hideSoftKeyboard();
}
private void moveCamera(LatLng latLng, float zoom, String title) {
Log.d(TAG, "moveCamera: moving the camera to: lat: " + latLng.latitude + ", lng: " + latLng.longitude);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoom));
if (!title.equals("My Location")) {
MarkerOptions options = new MarkerOptions()
.position(latLng)
.title(title);
mMap.addMarker(options);
}
hideSoftKeyboard();
}

private void initMap() {
Log.d(TAG, "initMap: initializing map..");
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(pharma2.this);
}
private void getLocationPermission() {
Log.d(TAG, "getLocationPermission: getting location permissions");
String[] permissions = {Manifest.permission.ACCESS_FINE_LOCATION,
Manifest.permission.ACCESS_COARSE_LOCATION};
if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
mLocationPermissionGranted = true;
initMap();
} else {
ActivityCompat.requestPermissions(this,
permissions, LOCATION_PERMISSION_REQUEST_CODE);
}
} else {
ActivityCompat.requestPermissions(this,
permissions, LOCATION_PERMISSION_REQUEST_CODE);
}
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
Log.d(TAG, "onRequestPermissionsResult: called");
mLocationPermissionGranted = false;
switch (requestCode) {
case LOCATION_PERMISSION_REQUEST_CODE: {
if (grantResults.length > 0) {
for (int i = 0; i < grantResults.length; i++) {
if (grantResults[i] != PackageManager.PERMISSION_GRANTED) {
mLocationPermissionGranted = false;
Log.d(TAG, "onRequestPermissionsResult: permission failed");
return;
}
}
Log.d(TAG, "onRequestPermissionsResult: permission granted");
mLocationPermissionGranted = true;
//initialize map
initMap();
}
}
}

}
private void hideSoftKeyboard() {
this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
}
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;
}

/*---------------------------------------------------------------------------------------------------------- */
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
/*---------------------------------------------------------------------------------------------------------- */
/*
----------------------Google Places Autocomplete suggesstions-------------------------------------------------------------
*/
private AdapterView.OnItemClickListener mAutocompleteClickListener = new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int i, long id) {
hideSoftKeyboard();
final AutocompletePrediction item = mPlaceAutocompleteAdapter.getItem(i);
final String placeId = item.getPlaceId();
PendingResult<PlaceBuffer> placeResult = Places.GeoDataApi
.getPlaceById(mGoogleApiClient ,placeId);
placeResult.setResultCallback(mUpdatePlaceDetailsCallback);
}
};
private ResultCallback<PlaceBuffer> mUpdatePlaceDetailsCallback = new ResultCallback<PlaceBuffer>() {
@Override
public void onResult(@NonNull PlaceBuffer places) {
if(!places.getStatus().isSuccess()){
Log.d(TAG, "onResult: PLace query did not complete successfully: " + places.getStatus().toString());
places.release();
return;
}
final Place place = places.get(0);
try{
mPlace = new PlaceInfo();
mPlace.setName(place.getName().toString());
Log.d(TAG, "onResult: name: " + place.getName());
mPlace.setAddress(place.getAddress().toString());
Log.d(TAG, "onResult: address: " + place.getAddress());
//      mPlace.setAttribution(place.getAttributions().toString());
//     Log.d(TAG, "onResult: attribution: " + place.getAttributions());
mPlace.setId(place.getId());
Log.d(TAG, "onResult: id: " + place.getId());
mPlace.setLatLng(place.getLatLng());
Log.d(TAG, "onResult: latlng: " + place.getLatLng());
mPlace.setRating(place.getRating());
Log.d(TAG, "onResult: rating: " + place.getRating());
mPlace.setPhoneNumber(place.getPhoneNumber().toString());
Log.d(TAG, "onResult: Phone Number:" + place.getPhoneNumber());
mPlace.setWebsiteUri(place.getWebsiteUri());
Log.d(TAG, "onResult: Website: " + place.getWebsiteUri());
Log.d(TAG, "onResult: place: " + mPlace.toString());
}catch(NullPointerException e){
Log.d(TAG, "onResult: NullPointerException: " + e.getMessage() );
}
moveCamera(new LatLng(place.getViewport().getCenter().latitude,
place.getViewport().getCenter().longitude), DEFAULT_ZOOM, mPlace);
places.release();
}
};


@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mMarker != null) {
mMarker.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("You are Here!");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE));
mMarker = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
Toast.makeText(pharma2.this, "Your Current Location",
Toast.LENGTH_LONG).show();
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
}

真的很想让这个应用程序工作，因为它是我的 Java 课程的年终项目。 任何帮助将不胜感激。

Answer 1

我认为它不起作用，因为您在OnCreate()方法中创建视图之前调用了该方法OnMapReady()。此外，您不会在任何地方initMap()调用该方法。

Answer 2

我认为你在这一部分有错误。

Button btnPharma = (Button) findViewById(R.id.btnPharma);
btnPharma.setOnClickListener(new View.OnClickListener(){});

您的activity_hosp2.xml没有btnPharmaid，因此它得到了Attempt to invoke virtual method on a null object reference当您尝试侦听空对象时。