Question

我正在使用Google Maps API开发应用程序。我试图添加一个标记，用户在地图上按下该标记，并在用户创建的标记之间绘制一条线。

我尝试添加方法SetOnMapClickListener，但每次在虚拟设备中运行我的应用程序时，它都会立即崩溃。我也尝试在OnCreate方法和OnMapReady中找到该方法，但这也不起作用。我成功地添加了新的标记，但只是写了它们......

在我发现的一些教程中，我看到他们使用mapFragment.getMap（）分配了谷歌地图对象，但我没有这种方法。谢谢！

这是我的代码：

package com.example.user.testmap;

import android.support.v4.app.FragmentActivity;
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;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

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

        mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
            @Override
            public void onMapClick(LatLng latLng) {
                double lit = latLng.latitude;
                double lon = latLng.longitude;
                        mMap.addMarker(new MarkerOptions().position(new LatLng(lit, lon)));

            }
        });
    }


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

        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-34, 151);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
        mMap.addMarker(new MarkerOptions().position(new LatLng(20, 5)));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(new LatLng(20, 5)));

    }

}

Answer 1

尝试删除mMap.setOnMapClickListener中的onCreate()，然后implements GoogleMap.OnMapClickListener

像这样。

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleMap.OnMapClickListener {

    private GoogleMap mMap;
    private ArrayList<Marker> arrMarkerList;
    private ArrayList<Polyline> arrPolylineList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // 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.setOnMapClickListener(this);
        arrMarkerList = new ArrayList<>();
        arrPolylineList = new ArrayList<>();
    }

    @Override
    public void onMapClick(LatLng latLng) {
        double lit = latLng.latitude;
        double lon = latLng.longitude;
        arrMarkerList.add(mMap.addMarker(new MarkerOptions().position(new LatLng(lit, lon))));

        // Removing the existing polyline to draw a new.
        for (Polyline polyline : arrPolylineList) {
            polyline.remove();
        }

        if (arrMarkerList.size() > 1) {
            PolylineOptions polylineOptions = new PolylineOptions();
            for (Marker marker : arrMarkerList) {
                polylineOptions.add(marker.getPosition());
            }
            arrPolylineList.add(mMap.addPolyline(polylineOptions));
        }
    }
}

如何在点击上添加无限标记 - 谷歌地图api

1 个答案: