google 地图中看不到多段线

Question

我正在尝试添加连接 google 中的一组点的折线 maps.When 我构建应用程序我没有收到任何错误，但折线没有 appear.If 我调用 isvisible( ) 方法 returns true.Please 帮助

@Override
public void onMapReady(GoogleMap googleMap) {
   // new LongOperation().execute("");

   /* googleMap.setMapStyle(
            MapStyleOptions.loadRawResourceStyle(
                    this, R.raw.mapjson));*/

    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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;
    }
    googleMap.setMyLocationEnabled(true);
    googleMapnew = googleMap;
    Polyline polyline1 = googleMap.addPolyline(new PolylineOptions()
            .clickable(true)
            .add(
                    new LatLng(13.034063, 77.567006 ),
                    new LatLng(13.034087, 77.568629),
                    new LatLng(13.034202, 77.569431),
                    new LatLng(13.034371, 77.570103),
                    new LatLng(13.034535, 77.570121),
                    new LatLng(13.036526, 77.570489),
                    new LatLng(13.037719, 77.570545),
                    new LatLng(13.038252, 77.570039),
                    new LatLng(13.039849, 77.570028),
                    new LatLng(13.040153, 77.569229),
                    new LatLng(13.040640, 77.568512),
                    new LatLng(13.041071, 77.567996),
                    new LatLng(13.041780, 77.567894))
    .color(Color.GREEN)
    .width(66));
    Log.e("polylog", String.valueOf(polyline1.isVisible()));
    Log.e("polylog", String.valueOf(polyline1));

}

Answer 1

问题在

googleMap.setMyLocationEnabled(true);

行，因为您可能没有向您的应用授予 ACCESS_FINE_LOCATION 和 ACCESS_COARSE_LOCATION。您应该通过 Android 设备的 Applications 菜单手动将其授予您的应用程序，或者像 Official Documentation and, for example, answer of Daniel Nugent 中那样实施检查和授予权限，例如：

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {

    private static final int LOCATION_PERMISSION_REQUEST_CODE = 101;
    private GoogleMap mGoogleMap;
    private MapFragment mMapFragment;

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

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

        mMapFragment = (MapFragment) getFragmentManager()
                .findFragmentById(R.id.map_fragment);
        mMapFragment.getMapAsync(this);
    }

    private void showPolyline() {

        mGoogleMap.setMyLocationEnabled(true);

        Polyline polyline1 = mGoogleMap.addPolyline(new PolylineOptions()
                .clickable(true)
                .add(
                        new LatLng(13.034063, 77.567006 ),
                        new LatLng(13.034087, 77.568629),
                        new LatLng(13.034202, 77.569431),
                        new LatLng(13.034371, 77.570103),
                        new LatLng(13.034535, 77.570121),
                        new LatLng(13.036526, 77.570489),
                        new LatLng(13.037719, 77.570545),
                        new LatLng(13.038252, 77.570039),
                        new LatLng(13.039849, 77.570028),
                        new LatLng(13.040153, 77.569229),
                        new LatLng(13.040640, 77.568512),
                        new LatLng(13.041071, 77.567996),
                        new LatLng(13.041780, 77.567894))
                .color(Color.GREEN)
                .width(66));

        mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(13.034063, 77.567006), 12));
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mGoogleMap = googleMap;

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            int locationPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
            if (locationPermission != PackageManager.PERMISSION_GRANTED) {
                makeLocationPermissionRequest();
            } else {
                showPolyline();
            }
        } else {
            showPolyline();
        }
}

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        switch (requestCode) {
            case LOCATION_PERMISSION_REQUEST_CODE: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    showPolyline();
                } else {
                }
                return;
            }
        }
    }

}

别忘了添加

到您的 AndroidManifest.xml 文件。你得到了类似的东西：

google 地图中看不到多段线

polyline not visible in google maps

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google-maps

google-polyline