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。