Android实现在map上画出路线的方法

本文实例讲述了Android实现在map上画出路线的方法。分享给大家供大家参考。具体如下：

最近在搞在地图上画出路线图，经过一段时间的摸索，终于搞明白了，其实也挺简单的，写个类继承Overlay，并重写draw方法，在draw方法中画出 path即可。对于Overaly，在地图上标记某个点或者画线之类的就要使用overlay，overlay相当于一个覆盖物，覆盖在地图上，这个覆盖物要自己实现所以要继承Overlay。

MapActivity.java如下：

package net.blogjava.mobile.map;
import java.util.List;
import Android.app.AlertDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.view.Menu;
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.Projection;
public class Main extends MapActivity {
private GeoPoint gpoint1, gpoint2, gpoint3;// 连线的点
@Override
public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);
 MapView mapView = (MapView) findViewById(R.id.mapview);
 mapView.setClickable(true);
 mapView.setBuiltInZoomControls(true);
 MapController mapController = mapView.getController();
 mapView.setTraffic(true);// 交通图
 // mapView.setSatellite(true);//卫星图
 // mapView.setStreetView(true);//街景
 MyOverlay myOverlay = new MyOverlay();
 mapView.getOverlays().add(myOverlay);
 mapController.setZoom(15);// 初始放大倍数
 gpoint1 = new GeoPoint((int) (24.477384 * 1000000),
 (int) (118.158216 * 1000000));
 gpoint2 = new GeoPoint((int) (24.488967 * 1000000),
 (int) (118.144277 * 1000000));
 gpoint3 = new GeoPoint((int) (24.491091 * 1000000),
 (int) (118.136781 * 1000000));
 mapController.animateTo(gpoint1);
}
@Override
protected boolean isRouteDisplayed() {
 // TODO Auto-generated method stub
 return false;
}
class MyOverlay extends Overlay {
 @Override
 public void draw(Canvas canvas, MapView mapView, boolean shadow) {
 // TODO Auto-generated method stub
 super.draw(canvas, mapView, shadow);
 // 画笔
 Paint paint = new Paint();
 paint.setColor(Color.RED);
 paint.setDither(true);
 paint.setStyle(Paint.Style.STROKE);
 paint.setStrokeJoin(Paint.Join.ROUND);
 paint.setStrokeCap(Paint.Cap.ROUND);
 paint.setStrokeWidth(2);
 Projection projection = mapView.getProjection();
 Point p1 = new Point();
 Point p2 = new Point();
 Point p3 = new Point();
 projection.toPixels(gpoint1, p1);
 projection.toPixels(gpoint2, p2);
 projection.toPixels(gpoint3, p3);
 Path path = new Path();
 path.moveTo(p1.x, p1.y);
 path.lineTo(p2.x, p2.y);
 path.lineTo(p3.x, p3.y);
 canvas.drawPath(path, paint);// 画出路径
 }
}
}

main.xml如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent">
 <com.google.android.maps.MapView
 android:id="@+id/mapview" android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:apiKey="0IB7Kn70qp1LT216Hhb-jmHJ8GLTie4p63O77KQ" />
</LinearLayout>

最后别忘了加权限 ：
 
<uses-permission Android:name="android.permission.INTERNET"/>
 
在<applacation></applacation>之间加<uses-library Android:name="com.google.android.maps" />

绘制路线图：

/**
* 通过解析google map返回的xml，在map中画路线图
*/
public void drawRoute(){
 String url = "http://maps.google.com/maps/api/directions/xml?origin=23.055291,113.391802" + "&destination=23.046604,113.397510&sensor=false&mode=walking";
 HttpGet get = new HttpGet(url);
 String strResult = "";
 try {
  HttpParams httpParameters = new BasicHttpParams();
  HttpConnectionParams.setConnectionTimeout(httpParameters, 3000);
  HttpClient httpClient = new DefaultHttpClient(httpParameters);
  HttpResponse httpResponse = null;
  httpResponse = httpClient.execute(get);
  if (httpResponse.getStatusLine().getStatusCode() == 200){
  strResult = EntityUtils.toString(httpResponse.getEntity());
  }
 } catch (Exception e) {
  return;
 }
 if (-1 == strResult.indexOf("<status>OK</status>")){
  Toast.makeText(this, "获取导航路线失败!", Toast.LENGTH_SHORT).show();
  this.finish();
  return;
 }
 int pos = strResult.indexOf("<overview_polyline>");
 pos = strResult.indexOf("<points>", pos + 1);
 int pos2 = strResult.indexOf("</points>", pos);
 strResult = strResult.substring(pos + 8, pos2);
 List<GeoPoint> points = decodePoly(strResult);
 MyOverLay mOverlay = new MyOverLay(points);
 List<Overlay> overlays = mMapView.getOverlays();
 overlays.add(mOverlay);
 if (points.size() >= 2){
  mMapController.animateTo(points.get(0));
 }
 mMapView.invalidate();
 }
/**
* 解析返回xml中overview_polyline的路线编码
*
* @param encoded
* @return
*/
private List<GeoPoint> decodePoly(String encoded) {
 List<GeoPoint> poly = new ArrayList<GeoPoint>();
 int index = 0, len = encoded.length();
 int lat = 0, lng = 0;
 while (index < len) {
  int b, shift = 0, result = 0;
  do {
  b = encoded.charAt(index++) - 63;
  result |= (b & 0x1f) << shift;
  shift += 5;
  } while (b >= 0x20);
  int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
  lat += dlat;
  shift = 0;
  result = 0;
  do {
  b = encoded.charAt(index++) - 63;
  result |= (b & 0x1f) << shift;
  shift += 5;
  } while (b >= 0x20);
  int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
  lng += dlng;
  GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6),(int) (((double) lng / 1E5) * 1E6));
  poly.add(p);
 }
 return poly;
}

希望本文所述对大家的Android程序设计有所帮助。