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：

<"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。