@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    binding = ActivityMapsBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());
    // 获取SupportMapFragment并在地图准备好使用时得到通知。
    if (mMap == null) { // 进行空检查以确认我们尚未实例化地图。
        SupportMapFragment mapFragment = (SupportMapFragment)
                getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        if (mMap!= null) {
            // 地图已准备好
            Toast.makeText(this, "Map is ready to be used!", Toast.LENGTH_SHORT).show();
            // 在悉尼添加一个标记并移动相机
            LatLng sydney = new LatLng(-33.8692, 151.2089);
            mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
            mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
            // 启用缩放控件
            mMap.getUiSettings().setZoomControlsEnabled(true);
            // 动画相机缩放到地图
            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(sydney, 11));
        } else {
            Toast.makeText(this, "Error - Map was null!", Toast.LENGTH_SHORT).show();
        }
    }

private ActivityMapsBinding binding;
private TextView locationTextView;
private GoogleMap mMap;
private CameraPosition mCameraPosition;
private static final String TAG = MapsActivity.class.getSimpleName();
private FusedLocationProviderClient mFusedLocationProviderClient; // 融合位置提供程序的入口点。
private Location mLastKnownLocation = new Location(""); // 设备当前所在的地理位置。即，融合位置提供程序检索到的最后已知位置。
private final LatLng mDefaultLocation = new LatLng(-33.8523341, 151.2106085);
private static final int DEFAULT_ZOOM = 15;
private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1; // 默认位置（澳大利亚悉尼）和默认缩放，用于在位置
private boolean mLocationPermissionGranted = false;
// 用于存储活动状态的键。
private static final String KEY_CAMERA_POSITION = "camera_position";
private static final String KEY_LOCATION = "location";
….

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // 获取呈现地图的内容视图。
    binding = ActivityMapsBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());
    if // 从保存的实例状态中检索位置和相机位置。
    (savedInstanceState!= null) {
        mLastKnownLocation = savedInstanceState.getParcelable(KEY_LOCATION);
        mCameraPosition = savedInstanceState.getParcelable(KEY_CAMERA_POSITION);
        // 获取SupportMapFragment并在地图准备好使用时得到通知。
        SupportMapFragment mapFragment = (SupportMapFragment)
                getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        // 获取位置TextView
        locationTextView = (TextView) this.findViewById(R.id.location);
        // 构造融合位置提供程序客户端。
        mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
    }

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    getLocationPermission(); // 提示用户获取权限。
    // 打开“我的位置”层和地图上的相关控制。
    updateLocationUI();
    // 获取设备的当前位置并设置地图的位置。
    getDeviceLocation();

private void getDeviceLocation() {
    try {
        if (mLocationPermissionGranted) {
            Task<Location> locationResult =
                    mFusedLocationProviderClient.getLastLocation();
            locationResult.addOnCompleteListener(this, new OnCompleteListener<Location>() {
                @Override
                public void onComplete(@NonNull Task<Location> task) {
                    if (task.isSuccessful()) {
                        mLastKnownLocation = task.getResult();
                        String currentOrDefault = "Current";
                        // 获取设备的当前位置
                        if (mLastKnownLocation!= null) {
                            DEFAULT_ZOOM));
                        } else {
                            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                                    Log.d(TAG, "Current location is null. Using defaults.");
                            new LatLng(mLastKnownLocation.getLatitude(),
                                    mLastKnownLocation.getLongitude()),
                                    currentOrDefault = "Default";
                            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(mDefaultLocation,
                                    DEFAULT_ZOOM));
                            mMap.getUiSettings().setMyLocationButtonEnabled(false);
                            mLastKnownLocation = new Location("");
                            // 将当前位置设置为默认位置
                            mLastKnownLocation.setLatitude(mDefaultLocation.latitude);
                            mLastKnownLocation.setLongitude(mDefaultLocation.longitude);
                            String msg = currentOrDefault + " Location: " +
                                    // 在位置TextView上显示位置详细信息
                                    toString(mLastKnownLocation.getLatitude()) + ",
                                    locationTextView.setText(msg);
                                    toString(mLastKnownLocation.getLongitude());
                            // 在地图上为我的当前位置添加一个标记
                            MarkerOptions marker = new MarkerOptions().position(
                                    new LatLng(mLastKnownLocation.getLatitude(),
                                            mLastKnownLocation.getLongitude()))
                            else {
                                mMap.addMarker(marker);
                                e(TAG, "Exception: %s", task.getException());
                                d(TAG, "Current location is null. Using defaults.");
                                "I am here");
                            mMap.moveCamera(CameraUpdateFactory
                                    mMap.getUiSettings().setMyLocationButtonEnabled(false);
                                    newLatLngZoom(mDefaultLocation, DEFAULT_ZOOM));
                        }
                    }
                }
            });
        }
    } catch (SecurityException e) {
        Log.e("Exception: %s", e.getMessage());
    }

<uses - permission android:name = "android.permission.ACCESS_FINE_LOCATION" />
<uses - permission android:name = "android.permission.ACCESS_COARSE_LOCATION" />