无法在 android studio 谷歌地图中获取标记和位置

Question

我对 android 开发还很陌生，我无法获取 gps 的当前位置并在地图上显示标记数组。

此外，我正在尝试按照此链接中的本教程绘制具有距离和时间计算的路径： https : //javapapers.com/android/draw-path-on-google-maps-android-api/

以及如何将具有唯一 ID 的 gps 坐标、距离和持续时间的值发送到 firebase 实时数据库

我哪里错了？

import androidx.fragment.app.FragmentActivity;
import android.annotation.SuppressLint;
import android.os.Bundle;
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;
import java.lang.reflect.Array;
import java.util.ArrayList;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    private Location currentLocation;
    private FusedLocationProviderClient fusedLocationProviderClient;
    private static final int LOCATION_REQUEST_CODE =101;

ArrayList<LatLng>arrayList=new ArrayList<LatLng>();
    LatLng route1 =  new LatLng(-35.016, 143.321);
    LatLng route2 = new LatLng(-34.747, 145.592);
    LatLng route3 = new LatLng(-34.364, 147.891);
    LatLng route4 = new LatLng(-33.501, 150.217);
    LatLng route5 = new LatLng(-32.306, 149.248);
    LatLng route6 = new LatLng(-32.491, 147.309);



    @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);
        arrayList.add(route1);
        arrayList.add(route2);
        arrayList.add(route3);
        arrayList.add(route4);
        arrayList.add(route5);
        arrayList.add(route6);


        fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
        if (ActivityCompat.checkSelfPermission(MapsActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MapsActivity.this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[] {android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_REQUEST_CODE);
            return;
        }
        fetchLastLocation();
    }
    private void fetchLastLocation(){
        Task<Location> task = fusedLocationProviderClient.getLastLocation();
        task.addOnSuccessListener(new OnSuccessListener<Location>() {
            @Override
            public void onSuccess(Location location) {
                if (location != null) {
                    currentLocation = location;
                    Toast.makeText(MapsActivity.this,currentLocation.getLatitude()+" "+currentLocation.getLongitude(),Toast.LENGTH_SHORT).show();
                    SupportMapFragment supportMapFragment= (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
                    supportMapFragment.getMapAsync(MapsActivity.this);
                }else{
                    Toast.makeText(MapsActivity.this,"No Location recorded",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        for (int i = 0; i < arrayList.size(); i++) {
            mMap.addMarker(new MarkerOptions().position(arrayList.get(i)).title("Marker"));

            LatLng latLng = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
            //MarkerOptions are used to create a new Marker.You can specify location, title etc with MarkerOptions
            MarkerOptions markerOptions = new MarkerOptions().position(latLng).title("You are Here");
            googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
            //Adding the created the marker on the map
            googleMap.addMarker(markerOptions);
        }
        @SuppressLint("NeedOnRequestPermissionsResult")
        @Override
        public void onRequestPermissionsResult ( int requestCode, String[] permissions,int[] grantResult){
            switch (requestCode) {
                case LOCATION_REQUEST_CODE:
                    if (grantResult.length > 0 && grantResult[0] == PackageManager.PERMISSION_GRANTED) {
                        fetchLastLocation();
                    } else {
                        Toast.makeText(MapsActivity.this, "Location permission missing", Toast.LENGTH_SHORT).show();
                    }
                    break;
            }
        }

    }
}

Answer 1

您已经定义了两次 SupportMapFragment 请检查我的代码是否工作正常我已经运行代码并解决了错误

 import android.content.pm.PackageManager; import android.location.Location; import android.os.Bundle; import android.widget.Toast; import androidx.annotation.NonNull; import androidx.core.app.ActivityCompat; import androidx.fragment.app.FragmentActivity; import com.google.android.gms.location.FusedLocationProviderClient; import com.google.android.gms.location.LocationServices; 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; import com.google.android.gms.tasks.OnSuccessListener; import com.google.android.gms.tasks.Task; import java.util.ArrayList; public class MapsActivity extends FragmentActivity implements OnMapReadyCallback { private GoogleMap mMap; private Location currentLocation; private FusedLocationProviderClient fusedLocationProviderClient; private static final int LOCATION_REQUEST_CODE = 101; ArrayList arrayList = new ArrayList(); LatLng route1 = new LatLng(-35.016, 143.321); LatLng route2 = new LatLng(-34.747, 145.592); LatLng route3 = new LatLng(-34.364, 147.891); LatLng route4 = new LatLng(-33.501, 150.217); LatLng route5 = new LatLng(-32.306, 149.248); LatLng route6 = new LatLng(-32.491, 147.309); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_maps); arrayList.add(route1); arrayList.add(route2); arrayList.add(route3); arrayList.add(route4); arrayList.add(route5); arrayList.add(route6); fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this); if (ActivityCompat.checkSelfPermission(MapsActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MapsActivity.this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_REQUEST_CODE); return; } fetchLastLocation(); } private void fetchLastLocation() { Task<Location> task = fusedLocationProviderClient.getLastLocation(); task.addOnSuccessListener(new OnSuccessListener<Location>() { @Override public void onSuccess(Location location) { if (location != null) { currentLocation = location; Toast.makeText(MapsActivity.this, currentLocation.getLatitude() + " " + currentLocation.getLongitude(), Toast.LENGTH_SHORT).show(); SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() .findFragmentById(R.id.map); mapFragment.getMapAsync(MapsActivity.this); } else { Toast.makeText(MapsActivity.this, "No Location recorded", Toast.LENGTH_SHORT).show(); } } }); } @Override public void onMapReady(GoogleMap googleMap) { mMap = googleMap; mMap.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() { @Override public void onMapLoaded() { for (int i = 0; i < arrayList.size(); i++) { mMap.addMarker(new MarkerOptions().position((LatLng) arrayList.get(i)).title("Marker")); LatLng latLng = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude()); //MarkerOptions are used to create a new Marker.You can specify location, title etc with MarkerOptions MarkerOptions markerOptions = new MarkerOptions().position(latLng).title("You are Here"); googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng,16)); //Adding the created the marker on the map googleMap.addMarker(markerOptions); } } }); } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResult) { switch (requestCode) { case LOCATION_REQUEST_CODE: if (grantResult.length > 0 && grantResult[0] == PackageManager.PERMISSION_GRANTED) { fetchLastLocation(); } else { Toast.makeText(MapsActivity.this, "Location permission missing", Toast.LENGTH_SHORT).show(); } break; } } }