根据经度纬度查询坐标并在google地图上显示

import java.util.List;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Point;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.groupdai.ncp.sign.R;

public class MyMapActivity extends MapActivity {
    /** Called when the activity is first created. */
    private MapController mapController;
    private MapView mapView;
    private MyOverLay myOverLay;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map);

        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        mapView = (MapView) this.findViewById(R.id.mapview);
        // 设置交通模式
        mapView.setTraffic(true);
        // 设置卫星模式
        mapView.setSatellite(false);
        // 设置街景模式
        mapView.setStreetView(false);
        // 设置缩放控制
        mapView.setBuiltInZoomControls(true);
        mapView.setClickable(true);
        mapView.setEnabled(true);
        // 得到MapController实例
        mapController = mapView.getController();
        mapController.setZoom(16);

        myOverLay = new MyOverLay();
        List<Overlay> overLays = mapView.getOverlays();
        overLays.add(myOverLay);
        Criteria criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_FINE);
        criteria.setAltitudeRequired(false);
        criteria.setBearingRequired(false);
        criteria.setCostAllowed(false);
        criteria.setPowerRequirement(Criteria.POWER_LOW);
        // 取得效果最好的Criteria
        String provider = locationManager.getBestProvider(criteria, true);
        // 得到Location
        Location location = locationManager.getLastKnownLocation(provider);
        updateWithLocation(location);
        // 注册一个周期性的更新，3秒一次
        locationManager.requestLocationUpdates(provider, 3000, 0,
                locationListener);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        menu.add(0, 1, 1, "交通模式");
        menu.add(0, 2, 2, "卫星模式");
        menu.add(0, 3, 3, "街景模式");

        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        super.onOptionsItemSelected(item);
        switch (item.getItemId()) {
        case 1:// 交通模式
            mapView.setTraffic(true);
            mapView.setSatellite(false);
            mapView.setStreetView(false);
            break;
        case 2:// 卫星模式
            mapView.setSatellite(true);
            mapView.setStreetView(false);
            mapView.setTraffic(false);
            break;
        case 3:// 街景模式
            mapView.setStreetView(true);
            mapView.setTraffic(false);
            mapView.setSatellite(false);
            break;
        default:
            mapView.setTraffic(true);
            mapView.setSatellite(false);
            mapView.setStreetView(false);
            break;
        }
        return true;
    }

    private void updateWithLocation(Location location) {
        if (location != null) {
            // 为绘制类设置坐标
            myOverLay.setLocation(location);
            GeoPoint geoPoint = new GeoPoint((int) (120.906033 * 1000000),
                    (int) (30.397700 * 1000000));
            // 定位到指定的坐标
            MyMapActivity.this.mapController.animateTo(geoPoint);
            mapController.setZoom(16);
        }
    }

    private final LocationListener locationListener = new LocationListener() {

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub

        }

        // 当坐标改变时出发此函数
        @Override
        public void onLocationChanged(Location location) {
            // TODO Auto-generated method stub
            updateWithLocation(location);
        }
    };

    class MyOverLay extends Overlay {

        private Location location;

        public void setLocation(Location location) {
            this.location = location;
        }

        @Override
        public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
                long when) {
            // TODO Auto-generated method stub
            super.draw(canvas, mapView, shadow);
            Paint paint = new Paint();
            Point myScreen = new Point();
            // 将经纬度换成实际屏幕的坐标。
            GeoPoint geoPoint = new GeoPoint((int) (((30.186252 * 1000000))),
                    (int)(120.28393 * 1000000));

            // 定位到指定的坐标
            MyMapActivity.this.mapController.setCenter(geoPoint);
            MyMapActivity.this.mapController.setZoom(16);
            mapView.getProjection().toPixels(geoPoint, myScreen);
            paint.setStrokeWidth(1);
            paint.setARGB(255, 255, 0, 0);
            paint.setStyle(Paint.Style.STROKE);
            Bitmap bmp = BitmapFactory.decodeResource(getResources(),
                    R.drawable.mypicture);
            // 把这张图片画到相应的位置。
            canvas.drawBitmap(bmp, myScreen.x, myScreen.y, paint);
            canvas.drawText("坐标所在位置", myScreen.x, myScreen.y, paint);
            MyMapActivity.this.mapController.animateTo(geoPoint);
            return true;
            

        }
    }

    @Override
    protected boolean isRouteDisplayed(){
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub

        if (keyCode == KeyEvent.KEYCODE_BACK) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setMessage("你确定退出吗？")
                    .setCancelable(false)
                    .setPositiveButton("确定",
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog,
                                        int id) {
                                    MyMapActivity.this.finish();
                                    android.os.Process
                                            .killProcess(android.os.Process
                                                    .myPid());
                                    android.os.Process
                                            .killProcess(android.os.Process
                                                    .myTid());
                                    android.os.Process
                                            .killProcess(android.os.Process
                                                    .myUid());
                                }
                            })
                    .setNegativeButton("返回",
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog,
                                        int id) {
                                    dialog.cancel();
                                }
                            });
            AlertDialog alert = builder.create();
            alert.show();
            return true;
        }

        return super.onKeyDown(keyCode, event);
    }
}

要实现在google地图上显示还要在机器上安装google地图，同时在mainfest.xml里面添加权限

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.groupdai.ncp.sign"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <uses-permission android:name="android.permission.WRITE_SETTINGS" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.CONTROL_LOCATION_UPDATES" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name="com.groupdai.ncp.serverdate.XMLParse"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.groupdai.ncp.Device.fpdevice"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
        </activity>
        <activity
            android:name="com.groupdai.ncp.map.MyMapActivity"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
        </activity>

 
        <uses-library android:name="com.google.android.maps" />
    </application>

 <span style="color:#FF6666;">   
    
    </span>
  

</manifest>

地图布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <com.google.android.maps.MapView
                 android:id="@+id/mapview"
                 android:layout_width="fill_parent"
                 android:layout_height="fill_parent"
                 android:apiKey="0e9EG9JLUpA-84Ldf8-scAchZder9DUGsfE0itA"
                 />

</LinearLayout>

其中apikey：为google地图申请的，具体申请流程请百度。