我正在开发一个需要在许多活动中获取当前位置的应用程序，为了使事情更容易，我创建了一个包含所有要求的类，并通过Method get location获取位置。不幸的是，我不断收到大量错误，这里是活动代码，类和错误消息。
这是活动
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
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.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class Acceuil extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_acceuil);
// 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);
}
/**
* 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;
Locate Obj = new Locate(getParent());
LatLng Loc=Obj.GetLocation();
// Add a Marker Containing Last Known Location Provided By The Main Fragment
LatLng Current = new LatLng(34.0132500,-6.8325500);
mMap.addMarker(new MarkerOptions().position(Current).title("Your Current Location"));
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Current, 15));
}
}
这是班级
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.widget.Toast;
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.model.LatLng;
/**
* Created by Otmane on 26/03/2016.
*/
public class Locate implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {
private final static int Play_services_resolution_request = 1000;
private Location mLocation;
private Location UpdatedLocation;
private GoogleApiClient mGoogleApiClient;
private boolean mRequestingLocationUpdates = false;
private LocationRequest mLocationRequest;
private static int Update_Interval = 10000; // 10 Seconds
private static int Fastest_Interval = 5000; // 5 Seconds
private static int Displacement = 10; // 10 meters
private Context mContext;
private boolean toggleUpdate= false;
public Locate(Context context) {
this.mContext = context;
try {
buildGoogleApiClient();
}
catch (Exception e )
{
/*AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(mContext);
alertDialogBuilder.setMessage("Unable To Connect To Location Services");
alertDialogBuilder.show();*/
}
createLocationRequest();
GetLocation();
}
public void setUpdate(boolean State)
{
this.toggleUpdate=State;
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(mContext)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
}
protected void createLocationRequest() {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(Update_Interval);
mLocationRequest.setFastestInterval(Fastest_Interval);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setSmallestDisplacement(Displacement);
}
protected void StartLocationUpdates() {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
protected void StopLocationUpdates() {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
public LatLng GetLocation() {
buildGoogleApiClient();
try{
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.*
LatLng Temp= new LatLng(0.0,0.0);
return Temp;
}
}
catch (Exception e)
{
//Toast.makeText(this,"Permissions Error",Toast.LENGTH_LONG).show();
}
mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (mLocation!=null){
LatLng Current = new LatLng(mLocation.getLatitude(),mLocation.getLongitude());
return Current;
}
LatLng Current = new LatLng(34.0132500,-6.8325500);
return Current;
}
public void onConnected(@Nullable Bundle bundle) {
GetLocation();
if (toggleUpdate== true ){
StartLocationUpdates();
}
}
@Override
public void onConnectionSuspended(int i) {
mGoogleApiClient.connect();
}
public LatLng GetUpdatedLocation(LatLng Loc){
return Loc;
}
@Override
public void onLocationChanged(Location location) {
UpdatedLocation=location;
if (UpdatedLocation != null){
LatLng temp = new LatLng(UpdatedLocation.getLatitude(),UpdatedLocation.getLongitude());
GetUpdatedLocation(temp);
}
else
{
LatLng temp = new LatLng(0.0,0.0);
GetUpdatedLocation(temp);
}
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Toast.makeText(mContext,"Connection Failed",Toast.LENGTH_SHORT).show();
}
}
这是错误讯息
53:41.486 14944-14944/otmos.pfe E/AndroidRuntime: FATAL EXCEPTION: main
Process: otmos.pfe, PID: 14944
java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Looper android.content.Context.getMainLooper()' on a null object reference
at com.google.android.gms.common.api.GoogleApiClient$Builder.<init>(Unknown Source)
at otmos.pfe.Locate.buildGoogleApiClient(Locate.java:56)
at otmos.pfe.Locate.GetLocation(Locate.java:90)
at otmos.pfe.Locate.<init>(Locate.java:48)
at otmos.pfe.Acceuil.onMapReady(Acceuil.java:38)
at com.google.android.gms.maps.SupportMapFragment$zza$1.zza(Unknown Source)
at com.google.android.gms.maps.internal.zzo$zza.onTransact(Unknown Source)
at android.os.Binder.transact(Binder.java:387)
at com.google.android.gms.maps.internal.v$a$a.a(:com.google.android.gms.alldynamite:82)
at maps.ei.bu$6.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
答案 0 :(得分：0)
我认为您可以找到使用com.google.android.gms的任何库都可能出现此问题。
如果您在android / app / build.gradle中引用了com.google.android.gms。 尝试为关联的库提供当前已安装的新版本。
我通过导航到[YOUR_ANDROID_SDK] / extras / google / m2repository / com / google / android / gms找到了我正在使用的库的版本号 然后找到可能导致问题的库，例如play-services-auth。
在那里你会看到所有的版本。将最新应用于build.gradle。 编译'com.google.android.gms：play-services：10.2.1'
还添加（GoogleApiClient Builder中需要gcm） 编译'com.google.android.gms：play-services-gcm：10.2.1'