在 Google 地图 v2 Android 上添加标记

Question

我按照教程中的

https://developers.google.com/maps/documentation/android/start

我设法将地图加载到我的应用程序中。现在我想使用纬度和经度在我的应用程序中添加一些标记。我该怎么做？我尝试了一些东西，但没有奏效。我试过的代码如下。

我打算这样做。但是我得到一个空点异常。这是什么原因？

GoogleMap googleMap = null;

           MapFragment fm = (MapFragment) (activity.getFragmentManager())
                    .findFragmentById(R.id.map);

           googleMap = fm.getMap();

            double latitude = 7.421226;
            double longitude =80.401264 ;

            // create marker
            MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("Hello Maps ");

            // adding marker
            googleMap.addMarker(marker); 

我的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/filmhall"
    android:background="@color/grey" >



<fragment 
          android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:name="com.google.android.gms.maps.SupportMapFragment"/> 

</LinearLayout>

Answer 1

看看我们在谷歌地图上添加标记的方法

mMap.addMarker(new MarkerOptions().position(new LatLng(22.7253, 75.8655)).title("Indore"));

这里是例子

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

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

public class BasicMapDemoActivity extends FragmentActivity
{
    private GoogleMap mMap;

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

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() 
    {
        if (mMap == null) 
        {
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
            if (mMap != null) 
            {
                setUpMap();
            }
        }
    }

    private void setUpMap() 
    {
        mMap.addMarker(new MarkerOptions().position(new LatLng(22.7253, 75.8655)).title("Indore"));
  // here is marker Adding code
    }
}

Example on Google Map

Answer 2

// latitude and longitude
double latitude = ;
double longitude = ;

// create marker
MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("Hello Maps ");

// adding marker
googleMap.addMarker(marker);

Answer 3

这是我的代码（它在地图中有 4 个图标，您只需将此类称为主要活动中的片段，它就会起作用，记住：在可绘制中创建一个图片并将其命名为“ atmpin2.png"):

package fragments;

import com.einstein.atm.R;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.Marker;

public class FragMapsGoogle extends MapFragment {
    GoogleMap map;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = super.onCreateView(inflater, container,
                savedInstanceState);
        map = getMap();
        LatLng place = new LatLng(21, 105.8);
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(place, 14.0f));


        DisplayMetrics displaymetrics = new DisplayMetrics();
        int w,h;
        this.getActivity().getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
        h = displaymetrics.heightPixels;
        w = displaymetrics.widthPixels;


        Bitmap bmp = BitmapFactory.decodeResource(
                    getResources(), R.drawable.atmpin2);
        float h2w2 = (float)bmp.getHeight()/bmp.getWidth();

        GoogleMap map = this.getMap();
        Toast.makeText(this.getActivity(), "Size Screen: "+h+"X"+w+"  "+h2w2, Toast.LENGTH_LONG).show();
        for (int i = 1; i < 5; i++) {
            MarkerOptions mkop = new MarkerOptions();
            place = new LatLng(21+i*0.00055, 105.8+i*0.00054);
            mkop.position(place);
            Marker maker = map.addMarker(mkop);
            maker.setIcon(BitmapDescriptorFactory.fromBitmap(Bitmap.createScaledBitmap(bmp, w/20+5, (int)((w/20+5)*h2w2), true)));

        }
        return rootView;
    }
}
// Ha Noi: 21.0226967,105.8369637

Answer 4

static final LatLng PERTH = new LatLng(-31.90, 115.86);
Marker perth = mMap.addMarker(new MarkerOptions()
                          .position(PERTH)
                          .draggable(true));

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