Android implements the method of drawing routes on map
- 2020-06-23 01:57:09
- OfStack
This article gives an example of an Android implementation that draws routes on map. Share to everybody for everybody reference. The details are as follows:
Recently, I was trying to draw the route line on the map. After 1 period of exploration, I finally figured it out. In fact, it is quite simple. For Overaly, to mark a point or draw a line on the map, overlay is used. overlay is equivalent to a overlay on the map. The overlay has to be self-implemented and therefore inherited from Overlay.
MapActivity. java as follows:
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;// Attachment points
@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);// Traffic map
// mapView.setSatellite(true);// Satellite imagery
// mapView.setStreetView(true);// Street view
MyOverlay myOverlay = new MyOverlay();
mapView.getOverlays().add(myOverlay);
mapController.setZoom(15);// Initial magnification
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);
// The brush
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);// Draw a path
}
}
}
main. xml as follows:
<?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>
Finally, don't forget to add permission:
<
uses-permission Android:name="android.permission.INTERNET"/
>
in
<
applacation
>
<
/applacation
>
between
<
uses-library Android:name="com.google.android.maps" /
>
Draw a roadmap:
/**
* By parsing google map The returned xml In the map Middle drawing route map
*/
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, " Failed to get navigation route !", 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();
}
/**
* Parsing return xml In the overview_polyline Route coding of
*
* @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;
}
I hope this article has been helpful for your Android programming.