Question

我的简单程序应该显示我的位置并将多段线绘制到在微调器中选择的位置。它目前只显示我的位置，但我不知道为什么。也许问题在于Android Marshmallow中引入的权限。这是我的代码：

    public class MapsActivity extends FragmentActivity {

    private final LatLng MainHousing = new LatLng(49.83511, 24.01446);
    private final LatLng FirstHousing = new LatLng(49.83533, 24.01004);
    private final LatLng FifthHousing = new LatLng(49.835, 24.00824);
    private static final int REQUEST_LOCATION = 1;
    private static String[] PERMISSIONS_STORAGE = {
            Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_COARSE_LOCATION
    };
    GoogleMap googleMap;
    Location location;
    LatLng myPosition;
    Spinner spinner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        List<String> list = new ArrayList<>();
        list.add("Головний корпус");
        list.add("I корпус");
        list.add("V корпус");

        spinner = (Spinner) findViewById(R.id.spinner);
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<>(this,
                android.R.layout.simple_spinner_item, list);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(dataAdapter);

        showMyLocation();
    }


    private void showMyLocation() {
        // Getting reference to the SupportMapFragment of activity_main.xml
        SupportMapFragment fm = (SupportMapFragment)
                getSupportFragmentManager().findFragmentById(R.id.map);

        // Getting GoogleMap object from the fragment
        googleMap = fm.getMap();

        // Enabling MyLocation Layer of Google Map
        googleMap.setMyLocationEnabled(true);

        // Getting LocationManager object from System Service LOCATION_SERVICE
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        // Creating a criteria object to retrieve provider
        Criteria criteria = new Criteria();

        // Getting the name of the best provider
        String provider = locationManager.getBestProvider(criteria, true);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this,
                    PERMISSIONS_STORAGE, REQUEST_LOCATION);
        }

        location = locationManager.getLastKnownLocation(provider);

        if (location != null) {
            // Getting latitude of the current location
            double latitude = location.getLatitude();

            // Getting longitude of the current location
            double longitude = location.getLongitude();

            // Creating a LatLng object for the current location
            LatLng latLng = new LatLng(latitude, longitude);

            myPosition = new LatLng(latitude, longitude);

            googleMap.addMarker(new MarkerOptions().position(myPosition).title("Start"));

            final PolylineOptions pOptions = new PolylineOptions();

            spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                    switch (spinner.getSelectedItemPosition()) {
                        case 0:
                            pOptions.add(myPosition).add(MainHousing).width(5).color(Color.BLUE).geodesic(true);
                            googleMap.addPolyline(pOptions);
                            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(MainHousing, 13));
                            break;
                        case 1:
                            pOptions.add(myPosition).add(FirstHousing).width(5).color(Color.BLUE).geodesic(true);
                            googleMap.addPolyline(pOptions);
                            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(FirstHousing, 13));
                            break;
                        case 2:
                            pOptions.add(myPosition).add(FifthHousing).width(5).color(Color.BLUE).geodesic(true);
                            googleMap.addPolyline(pOptions);
                            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(FifthHousing, 13));
                            break;
                    }
                }

                @Override
                public void onNothingSelected(AdapterView<?> parent) {

                }
            });
        }
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions,
                                           int[] grantResults) {
        switch (requestCode) {
            case REQUEST_LOCATION:
                if (grantResults.length > 0 &&
                        grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    // Permission Granted
                } else {
                    // Permission Denied
                    Toast.makeText(MapsActivity.this, "LOCATION Denied", Toast.LENGTH_SHORT)
                            .show();
                }
                break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }
}

那么，我的问题是什么？它可能是一个愚蠢的，因为我是android的新手。提前谢谢。

Answer 1

首先，您需要实现OnMapReady接口以及ConnectionCallbacks，因为它需要一些时间来加载地图并将您的逻辑移动到onConnected（）方法，在那里您将询问用户的位置并设置您的微调器与折线。

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.location.Location;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.support.v4.content.ContextCompat;
import android.view.View;
import android.widget.*;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.*;
import com.google.android.gms.maps.*;
import com.google.android.gms.maps.model.*;

import java.util.ArrayList;
import java.util.List;

public class MapsActivity extends FragmentActivity
    implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private final LatLng MainHousing = new LatLng(49.83511, 24.01446);
    private final LatLng FirstHousing = new LatLng(49.83533, 24.01004);
    private final LatLng FifthHousing = new LatLng(49.835, 24.00824);
    private static final int REQUEST_LOCATION = 1;

    GoogleMap googleMap;
    LatLng myPosition;
    Spinner spinner;
    PolylineOptions pOptions;
    Marker currLocationMarker;
    SupportMapFragment mFragment;
    LocationRequest mLocationRequest;
    GoogleApiClient mGoogleApiClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        List<String> list = new ArrayList<>();
        list.add("Головний корпус");
        list.add("I корпус");
        list.add("V корпус");

        spinner = (Spinner) findViewById(R.id.spinner);
        pOptions = new PolylineOptions();

        ArrayAdapter<String> dataAdapter = new ArrayAdapter<>(this,
            android.R.layout.simple_spinner_item, list);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(dataAdapter);

        mFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mFragment.getMapAsync(this);

    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions,
                                       int[] grantResults) {
        switch (requestCode) {
            case REQUEST_LOCATION:
                if (grantResults.length > 0 &&
                    grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // Permission Granted
                    Toast.makeText(SOMapsActivity.this, "LOCATION Accepted", Toast.LENGTH_SHORT)
                        .show();
                } else {
                // Permission Denied
                    Toast.makeText(SOMapsActivity.this, "LOCATION Denied", Toast.LENGTH_SHORT)
                        .show();
                }
                break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        this.googleMap = googleMap;
        buildGoogleApiClient();
        mGoogleApiClient.connect();
    }

    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }


    @Override
    public void onConnected(@Nullable Bundle bundle) {

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED ||
            ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
            ) {

            ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION},
                REQUEST_LOCATION);
        }

        Location mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
            mGoogleApiClient);
        if (mLastLocation != null) {

            myPosition = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
            MarkerOptions markerOptions = new MarkerOptions();
            markerOptions.position(myPosition);
            markerOptions.title("Current Position");
            markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
            currLocationMarker = googleMap.addMarker(markerOptions);
        }

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(5000); //5 seconds
        mLocationRequest.setFastestInterval(3000); //3 seconds
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
    //mLocationRequest.setSmallestDisplacement(0.1F); //1/10 meter

        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                switch (spinner.getSelectedItemPosition()) {
                    case 0:
                        pOptions.add(myPosition).add(MainHousing).width(5).color(Color.BLUE).geodesic(true);
                        googleMap.addPolyline(pOptions);
                        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(MainHousing, 17));
                        break;
                    case 1:
                        pOptions.add(myPosition).add(FirstHousing).width(5).color(Color.BLUE).geodesic(true);
                        googleMap.addPolyline(pOptions);
                        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(FirstHousing, 17));
                        break;
                    case 2:
                        pOptions.add(myPosition).add(FifthHousing).width(5).color(Color.BLUE).geodesic(true);
                        googleMap.addPolyline(pOptions);
                            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(FifthHousing, 17));
                        break;
                    }
                }

                @Override
                public void onNothingSelected(AdapterView<?> parent) {
                }
            });
        }
//......
}

P.S。这段代码有效，但可以改进，所以请务必花一些时间来分析它并根据自己的目的进行修改。

P.p.s。在此示例中，多边形线未被删除，因此您可能还会编写一些删除它们的代码。

干杯。

我的简单程序显示了我的位置，但没有显示在微调器中选择的位置的折线

1 个答案: