TODO：对上一篇随笔：Step by Step——Google Map View（Hello View） 进行进一步改进，使其能够获取设备当前位置，并显示对应地图
step1：定义LocationManager，获取当前location，并封装成GeoPoint
locationManager = (LocationManager) GMapTest.this
.getSystemService(Context.LOCATION_SERVICE);
/**
* get Point
*
* @return
*/
private GeoPoint getCurrentGeoPoint() {
String context = Context.LOCATION_SERVICE;
String provider = LocationManager.GPS_PROVIDER;
Location location = locationManager.getLastKnownLocation(provider);
if (location == null) { // 没有最后位置，更新gps,获取当前位置
locationManager.requestLocationUpdates(provider, 0, 0,
new MyLocationListener());
location = locationManager.getLastKnownLocation(provider);
}
GeoPoint point = null;
if (location == null) {
Double lat = 37.422006 * 1E6; // 默认值
Double lng = -122.084095 * 1E6;
point = new GeoPoint(lat.intValue(), lng.intValue());
} else // 当前反馈的GPS位置
{
Double lat = location.getLatitude() * 1E6;
Double lng = location.getLongitude() * 1E6;
point = new GeoPoint(lat.intValue(), lng.intValue());
System.out.println(lat);
System.out.println(lng);
}
return point;
}
step2：在对应的Point上显示标记
/**
* 显示标记
*
* @param point
*/
private void displayMark(GeoPoint point) {
OverlayItem overlayitem = new OverlayItem(point, "我是个胖纸!", "我在这!");
itemizedoverlay.addOverlay(overlayitem);
}
注：为了不让标记重复显示，在ItemizedOverlay的子类里追加一个remove方法：
/**
* remove
*
* @param index
*/
public void removeOverlay(int index) {
mOverlays.remove(index);
populate();
}
修改
displayMark 方法：
/**
* 显示标记
*
* @param point
*/
private void displayMark(GeoPoint point) {
OverlayItem overlayitem = new OverlayItem(point, "我是个胖纸!", "我在这!");
if (itemizedoverlay.size() != 0) {
itemizedoverlay.removeOverlay(0);
}
itemizedoverlay.addOverlay(overlayitem);
}
step3：获得当前Location对用Point，将Point上加Mark，并将该图层加到MapOverlays：
GeoPoint point = getCurrentGeoPoint();
displayMark(point);
mapOverlays.add(itemizedoverlay);
step4：调整Map状态，显示对应位置的地图：
mapcontroller = mapView.getController();
mapcontroller.setCenter(point);
mapcontroller.setZoom(15);
mapcontroller.animateTo(point);
step5：定义LocationListener，监听每次Location的变化，并实时的更新地图上的显示：
/**
* LocationListener
*
* @author Ying_er
* @Email melody.crazycoding@gmail.com
* @time 2011/10/14 9:30:51
* @version 1.00
*/
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
Double lat = location.getLatitude() * 1E6;
Double lng = location.getLongitude() * 1E6;
GeoPoint point = new GeoPoint(lat.intValue(), lng.intValue());
mapcontroller.setCenter(point);
mapcontroller.animateTo(point);
displayMark(point);
System.out.println("locationChanged");
System.out.println(location.getLatitude());
System.out.println(location.getLongitude());
}
@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
}
}
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,
0, new MyLocationListener());
附：MapActivity（GMapTest）完整代码：
package com.yinger;
import java.util.List;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
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.google.android.maps.OverlayItem;
/**
*
* @author Ying_er
* @Email melody.crazycoding@gmail.com
* @time 2011/10/13 10:37:10
* @version 1.00
*/
public class GMapTest extends MapActivity {
MapView mapView = null;
LocationManager locationManager = null;
MapController mapcontroller = null;
HelloItemizedOverlay itemizedoverlay = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mapView = (MapView) findViewById(R.id.mapview);
/**
* 是否显示街道信息
*/
mapView.setStreetView(true);
/**
* 是否显示交通信息
*/
mapView.setTraffic(true);
/**
* 是否显示卫星图
*/
mapView.setSatellite(false);
mapView.setBuiltInZoomControls(true);
locationManager = (LocationManager) GMapTest.this
.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,
0, new MyLocationListener());
/**
* 得到所有图层对象
*/
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(
R.drawable.androidmarker);
itemizedoverlay = new HelloItemizedOverlay(drawable, this);
GeoPoint point = getCurrentGeoPoint();
displayMark(point);
mapOverlays.add(itemizedoverlay);
mapcontroller = mapView.getController();
mapcontroller.setCenter(point);
mapcontroller.setZoom(15);
mapcontroller.animateTo(point);
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
/**
* 显示标记
*
* @param point
*/
private void displayMark(GeoPoint point) {
OverlayItem overlayitem = new OverlayItem(point, "我是个胖纸!", "我在这!");
if (itemizedoverlay.size() != 0) {
itemizedoverlay.removeOverlay(0);
}
itemizedoverlay.addOverlay(overlayitem);
}
/**
* get Point
*
* @return
*/
private GeoPoint getCurrentGeoPoint() {
String context = Context.LOCATION_SERVICE;
String provider = LocationManager.GPS_PROVIDER;
Location location = locationManager.getLastKnownLocation(provider);
if (location == null) { // 没有最后位置，更新gps,获取当前位置
locationManager.requestLocationUpdates(provider, 0, 0,
new MyLocationListener());
location = locationManager.getLastKnownLocation(provider);
}
GeoPoint point = null;
if (location == null) {
Double lat = 37.422006 * 1E6; // 默认值
Double lng = -122.084095 * 1E6;
point = new GeoPoint(lat.intValue(), lng.intValue());
} else // 当前反馈的GPS位置
{
Double lat = location.getLatitude() * 1E6;
Double lng = location.getLongitude() * 1E6;
point = new GeoPoint(lat.intValue(), lng.intValue());
System.out.println(lat);
System.out.println(lng);
}
return point;
}
/**
* LocationListener
*
* @author Ying_er
* @Email melody.crazycoding@gmail.com
* @time 2011/10/14 9:30:51
* @version 1.00
*/
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
Double lat = location.getLatitude() * 1E6;
Double lng = location.getLongitude() * 1E6;
GeoPoint point = new GeoPoint(lat.intValue(), lng.intValue());
mapcontroller.setCenter(point);
mapcontroller.animateTo(point);
displayMark(point);
System.out.println("locationChanged");
System.out.println(location.getLatitude());
System.out.println(location.getLongitude());
}
@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
}
}
}
ItemizedOverlay（HelloItemizedOverlay）完整代码：
package com.yinger;
import java.util.ArrayList;
import android.app.AlertDialog;
import android.content.Context;
import android.graphics.drawable.Drawable;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;
/**
* 在MapView之上，创建一个图层（OverlayItem） 生成该类对象，并将该对象添加到MapView.getOverlays()里
* 一个OverlayItem对象就代表了一个在地图上显示的标记
*
* @author Ying_er
* @Email melody.crazycoding@gmail.com
* @time 2011/10/12 14:53:17
* @version 1.00
*/
public class HelloItemizedOverlay extends ItemizedOverlay<OverlayItem> {
/**
* 创建一个List对象，存储该图层中所有的标记对象
*/
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
private Context context;
/**
* 参数用于指定显示标记的默认图片
*
* @param arg0
*/
public HelloItemizedOverlay(Drawable arg0) {
super(boundCenterBottom(arg0));
// TODO Auto-generated constructor stub
}
public HelloItemizedOverlay(Drawable arg0, Context context) {
super(boundCenterBottom(arg0));
// TODO Auto-generated constructor stub
this.context = context;
}
/**
* 创建一个OverlayItem对象
*/
@Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return mOverlays.get(i);
}
/**
* 返回当前Overlay中的OverlayItem对象个数
*/
@Override
public int size() {
// TODO Auto-generated method stub
return mOverlays.size();
}
/**
* 将生成好的OverlayItem对象添加到List当中
*
* @param overlay
*/
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}
/**
* remove
*
* @param index
*/
public void removeOverlay(int index) {
mOverlays.remove(index);
populate();
}
/**
* 当用户点击标记时所执行的操作
*/
@Override
protected boolean onTap(int index) {
OverlayItem item = mOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(context);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}
}
posted on 2011-10-14 10:01
Ying-er 阅读(1574)
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