Java Can'；t在谷歌地图活动中导航，它总是返回到我当前的位置

我是android开发新手，正在开发一款需要谷歌地图活动的应用程序。 我面临的问题是，当我试图在地图上平移（或滚动）时，我会立即恢复到最初设置的当前位置。 一点帮助将是非常好的，因为我被困在这一点上，无法找到解决办法。 代码如下：-

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    binding = ActivityMapsBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());

    // 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);
}



@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.getUiSettings().setScrollGesturesEnabled(true);
    locationManager=(LocationManager)this.getSystemService(Context.LOCATION_SERVICE);
    locationListener=new LocationListener() {
        @Override
        public void onLocationChanged(@NonNull Location location) {
            centerOnMap(location,"Your Location");
        }
    };

    if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED)
    {
        ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);
    }
    else{
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
        Location lastKnownLocation=locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        centerOnMap(lastKnownLocation,"Your Location");
    }
}

public void centerOnMap(Location location,String address)
{
    LatLng userLocation = new LatLng(location.getLatitude(),location.getLongitude());
    mMap.addMarker(new MarkerOptions().position(userLocation).title(address));
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 15));
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull @org.jetbrains.annotations.NotNull String[] permissions, @NonNull @org.jetbrains.annotations.NotNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED)
    {
        if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION)==PackageManager.PERMISSION_GRANTED){
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
        }

    }
}

---

}

您可能有但未说明的一项要求是：

当

lastLocation

可用且用户已 未移动地图，然后将地图居中放置在该位置。如果 用户已移动地图，请不要将地图居中In 无论哪种情况，在用户位置添加一个标记

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

private GoogleMap mMap;

FusedLocationProviderClient mFusedLocationClient;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);

}

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.getUiSettings().setScrollGesturesEnabled(true);

    getLastLocation();
    mMap.setOnMapLongClickListener(new GoogleMap.OnMapLongClickListener() {
        @Override
        public void onMapLongClick(@NonNull LatLng latLng) {

            Location location = new Location(LocationManager.GPS_PROVIDER);
            location.setLatitude(latLng.latitude);
            location.setLongitude(latLng.longitude);
            centerOnMap(location,"Your location");
        }
    });
}


@SuppressLint("MissingPermission")
private void getLastLocation() {
    if (checkPermissions()) {
        if (isLocationEnabled()) {
            mFusedLocationClient.getLastLocation().addOnCompleteListener(new OnCompleteListener<Location>() {
                @Override
                public void onComplete(@NonNull Task<Location> task) {
                    Location location = task.getResult();
                    if (location == null) {
                        requestNewLocationData();
                    } else {
                        centerOnMap(location,"Your Location");
                    }
                }
            });
        } else {
            Toast.makeText(this, "Please turn on" + " your location...", Toast.LENGTH_LONG).show();
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }
    } else {
        requestPermissions();
    }
}

@SuppressLint("MissingPermission")
private void requestNewLocationData() {
    LocationRequest mLocationRequest = new LocationRequest();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    mLocationRequest.setInterval(5);
    mLocationRequest.setFastestInterval(0);
    mLocationRequest.setNumUpdates(1);
    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
}

private LocationCallback mLocationCallback = new LocationCallback() {

    @Override
    public void onLocationResult(LocationResult locationResult) {
        Location mLastLocation = locationResult.getLastLocation();
        centerOnMap(mLastLocation,"Your Location");
    }
};

private boolean checkPermissions() {
    return ActivityCompat.checkSelfPermission(this,   Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED;
}

private void requestPermissions() {
    ActivityCompat.requestPermissions(this, new String[]{
            Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}

private boolean isLocationEnabled() {
    LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) || locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

public void centerOnMap(Location location,String address)
{
    LatLng userLocation = new LatLng(location.getLatitude(),location.getLongitude());
    mMap.clear();
    mMap.addMarker(new MarkerOptions().position(userLocation).title(address));
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 15));
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED)
    {
        getLastLocation();
    }
}

在走得太远之前，必须注意谷歌地图提供了 功能类似于您试图实现的功能，但您仍然需要“移动相机”。标记是一个蓝色的球，而不是典型的标记。请参阅

myMap.setMyLocationEnabled（true）

。就这样！在获得地图权限后执行此操作

但是如果你不想使用它，那么这里是你需要的简单更改

请记住，

LocationManager

getLastKnownLocation

可以返回 如果设备没有（尚未）设置，则为null。所以我推荐一个小的 更改一点无关的内容-只需让位置侦听器完成所有工作，并摆脱以下一种特殊情况：

// this is where you initially check permissions and have them.
else{
    locationManager.requestLocationUpdates (LocationManager.GPS_PROVIDER,0,0,locationListener);
    // Here I removed the last location centering and let the
    // location listener always handle it.
}

这就打开了可能性 用户可以与地图交互，最终到达最后一个位置。我理解这是你试图解决的问题

（顺便说一句，在我看来，你把

android.location.LocationManager

和 FusedLocationProviderApi（com.google.android.gms.location）的

FusedLocationProviderApi，因此我无法获取您的
由于不兼容的
LocationListener
s，要编译的代码。
不幸的是，GoogleMaps有两个
LocationListener
类
为了确保进一步了解，您必须包含您的导入。）

无论如何

当地图第一次准备就绪（
onMapReady
）时，地图的摄像头将被关闭
以
（0,0）
为中心。您可以获取摄像机的目标位置（中心）
随时使用
LatLng tgtCtr=mMap.getCameraPosition（）.target

奇怪的是，要知道用户是否
以任何方式与地图交互：滚动事件生成相机
触摸事件时的更改会生成单独的事件。相机更换
无法独占使用，因为您的代码或用户只能
不移动地图的缩放。你可以走这条路，但是
为了回答这个问题，为了简单起见，摄像机
使用目标

声明类实例变量（与定义
mMap
的区域相同）：

因此，在分配
mMap
后的
onMapReady
中，执行以下操作：

tgtCtr = mMap.getCameraPosition().target;

因此，假设您的代码在发布时存在（非常接近），然后
改变可能有助于：

// This change simply restricts centering of the map on location
// update to only when user has not moved the map (scrolled).

@Override
public void onLocationChanged(@NonNull Location location) {
    LatLng currentCtr = mMap.getCamaraPosition().target;
    
    // This is not the ideal check since `double` comparisons 
    // should account for epsilon but in this case of (0,0) it should work.
    
    // Alternatively you could compute the distance of current
    // center to (0,0) and then use an epsilon: 
    //    see `com.google.maps.android.SphericalUtil.computeDistanceBetween`.
    
    if (currentCtr.latitude == 0 && currentCtr.longitude == 0) {
        centerOnMap(location,"Your Location");
    }
}

保存为用户添加的标记似乎也是一个好主意
位置-这是可选的，但可以方便地防止多个标记
从添加到该位置：

// Define a class instance variable
Marker myLocMarker = nulll;

// and then in centerOnMap
public void centerOnMap(Location location, String address)
{
    // ... other code

    if (myLocMarker == null) {
        myLocMarker = mMap.addMarker(new MarkerOptions().position(userLocation).title(address));
    }

    // ... more code
}

所以，真正的唯一困难是弄清楚“有
用户移动了地图。“在这种情况下，根据最初的要求
您可能不想移动地图。
正如您在评论部分提到的，请使用FusedLocationProviderClient而不是LocationManager。
在应用程序级渐变中添加
实现'com.google.android.gms:play services location:17.0.0'
。别忘了为精细位置添加清单权限

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

private GoogleMap mMap;

FusedLocationProviderClient mFusedLocationClient;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);

}

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.getUiSettings().setScrollGesturesEnabled(true);

    getLastLocation();
    mMap.setOnMapLongClickListener(new GoogleMap.OnMapLongClickListener() {
        @Override
        public void onMapLongClick(@NonNull LatLng latLng) {

            Location location = new Location(LocationManager.GPS_PROVIDER);
            location.setLatitude(latLng.latitude);
            location.setLongitude(latLng.longitude);
            centerOnMap(location,"Your location");
        }
    });
}


@SuppressLint("MissingPermission")
private void getLastLocation() {
    if (checkPermissions()) {
        if (isLocationEnabled()) {
            mFusedLocationClient.getLastLocation().addOnCompleteListener(new OnCompleteListener<Location>() {
                @Override
                public void onComplete(@NonNull Task<Location> task) {
                    Location location = task.getResult();
                    if (location == null) {
                        requestNewLocationData();
                    } else {
                        centerOnMap(location,"Your Location");
                    }
                }
            });
        } else {
            Toast.makeText(this, "Please turn on" + " your location...", Toast.LENGTH_LONG).show();
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }
    } else {
        requestPermissions();
    }
}

@SuppressLint("MissingPermission")
private void requestNewLocationData() {
    LocationRequest mLocationRequest = new LocationRequest();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    mLocationRequest.setInterval(5);
    mLocationRequest.setFastestInterval(0);
    mLocationRequest.setNumUpdates(1);
    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
}

private LocationCallback mLocationCallback = new LocationCallback() {

    @Override
    public void onLocationResult(LocationResult locationResult) {
        Location mLastLocation = locationResult.getLastLocation();
        centerOnMap(mLastLocation,"Your Location");
    }
};

private boolean checkPermissions() {
    return ActivityCompat.checkSelfPermission(this,   Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED;
}

private void requestPermissions() {
    ActivityCompat.requestPermissions(this, new String[]{
            Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}

private boolean isLocationEnabled() {
    LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) || locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

public void centerOnMap(Location location,String address)
{
    LatLng userLocation = new LatLng(location.getLatitude(),location.getLongitude());
    mMap.clear();
    mMap.addMarker(new MarkerOptions().position(userLocation).title(address));
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 15));
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED)
    {
        getLastLocation();
    }
}

公共类MapsActivity扩展了FragmentActivity在MapreadyCallback上的实现{
私有谷歌地图；
FusedLocationProviderClient mFusedLocationClient；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_映射）；
SupportMapFragment mapFragment=（SupportMapFragment）getSupportFragmentManager（）
.findFragmentById（R.id.map）；
getMapAsync（这个）；
mFusedLocationClient=LocationServices.getFusedLocationProviderClient（此）；
}
@凌驾
4月1日公开作废（谷歌地图谷歌地图）{
mMap=谷歌地图；
mMap.getUiSettings（）.setScrollGesturesEnabled（true）；
getLastLocation（）；
mMap.setOnMapLongClickListener（新的GoogleMap.OnMapLongClickListener（）{
@凌驾
单击时的公共无效（@NonNull LatLng LatLng）{
位置=新位置（LocationManager.GPS\U提供程序）；
位置。设置纬度（纬度）；
位置设置经度（纬度经度）；
centerOnMap（位置，“您的位置”）；
}
});
}
@SuppressLint（“丢失许可”）
私有void getLastLocation（）{
if（checkPermissions（））{
如果（isLocationEnabled（））{
mFusedLocationClient.getLastLocation（）.addOnCompleteListener（新的OnCompleteListener（）{
@凌驾
未完成的公共void（@NonNull任务）{
位置=task.getResult（）；
if（位置==null）{
requestNewLocationData（）；
}否则{
centerOnMap（位置，“您的位置”）；
}
}
});
}否则{
Toast.makeText（这是“请打开”+“您的位置…”），Toast.LENGTH\u LONG.show（）；
意向意向=新意向（设置、动作、位置、来源、设置）；
星触觉（意向）；
}
}否则{
请求权限（）；
}
}
@SuppressLint（“丢失许可”）
私有void requestNewLocationData（）{
LocationRequest MLLocationRequest=新的LocationRequest（）；
mLocationRequest.setPriority（位置请求.优先级高精度）；
位置