Android实现在map上画出路线的方法

2020-04-11 11:28:19

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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。

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