Adding Overlay to OSMDROID

问题:

I have been struggling with this long time. I am trying to add Overlay on my map. I am using the open source OSMdroid. but all I get by the example is a straight red line from one corner to another. My target is to add some icon where my geoPoint is set.

here is my code:

 package osmdemo.demo;

import java.util.List;

import microsoft.mappoint.TileSystem;

import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapController;
import org.osmdroid.views.MapView;
import org.osmdroid.views.MapView.Projection;
import org.osmdroid.views.overlay.Overlay;
import org.osmdroid.views.overlay.ScaleBarOverlay;
import org.osmdroid.views.util.constants.MapViewConstants;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Rect;
import android.location.LocationManager;
import android.os.Bundle;

public class map extends Activity implements MapViewConstants
{

    /** Called when the activity is first created. */

    protected static final String PROVIDER_NAME = LocationManager.GPS_PROVIDER;
    MapController mapController;
    MapView mapView;
    ScaleBarOverlay mScaleBarOverlay;
    private MapOverlay mmapOverlay = null;
    private LocationManager mLocMgr;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mapView = (MapView) findViewById(R.id.mapview);

        mapView.setTileSource(TileSourceFactory.MAPNIK);
        mapView.setBuiltInZoomControls(true);
        mapView.setMultiTouchControls(true);

        mapController = mapView.getController();
        mapController.setZoom(20);
        GeoPoint point2 = new GeoPoint(31.987968, 34.783069);
        mapController.setCenter(point2);

        this.mmapOverlay = new MapOverlay(this);

        List<Overlay> listOfOverlays = mapView.getOverlays();
        listOfOverlays.add(mmapOverlay);
        mapView.invalidate();
    }

    public class MapOverlay extends org.osmdroid.views.overlay.Overlay
    {

        public MapOverlay(Context ctx)
        {
            super(ctx);
            // TODO Auto-generated constructor stub
        }

        @Override
        protected void draw(Canvas pC, MapView pOsmv, boolean shadow)
        {
            if (shadow)
                return;

            Paint lp3;
            lp3 = new Paint();
            lp3.setColor(Color.RED);
            lp3.setAntiAlias(true);
            lp3.setStyle(Style.STROKE);
            lp3.setStrokeWidth(1);
            lp3.setTextAlign(Paint.Align.LEFT);
            lp3.setTextSize(12);
            // Calculate the half-world size
            final Rect viewportRect = new Rect();
            final Projection projection = pOsmv.getProjection();
            final int zoomLevel = projection.getZoomLevel();
            int mWorldSize_2 = TileSystem.MapSize(zoomLevel) / 2;

            // Save the Mercator coordinates of what is on the screen
            viewportRect.set(projection.getScreenRect());
            // DON'T set offset with either of below
            // viewportRect.offset(-mWorldSize_2, -mWorldSize_2);
            // viewportRect.offset(mWorldSize_2, mWorldSize_2);

            // Draw a line from one corner to the other
            pC.drawLine(viewportRect.left, viewportRect.top,
                    viewportRect.right, viewportRect.bottom, lp3);
        }

        public void onProviderDisabled(String arg0)
        {
        }

        public void onProviderEnabled(String provider)
        {
        }

    }

}

thats my Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.test.overlay" android:versionCode="1" android:versionName="1.0">
    <uses-sdk android:minSdkVersion="3" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />


    <application >
        <activity android:name=".OverlayDemo" android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
</manifest>

Thanks in advance,

ray.

回答1:

The jars versions 3.0.3 and 3.0.4 seem to have changed a bit since the sample code was written.

If you are basing your app on the code as quoted in the previous answer, then change the line

mResourceProxy = new ResourceProxyImpl(getApplicationContext());

to

mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());

This should at least get you going with a default icon.

EDIT

This should centre the map just NE of Liverpool and put an icon just off centre.

package osmdemo.demo;

import java.util.ArrayList;
import org.osmdroid.DefaultResourceProxyImpl;
import org.osmdroid.ResourceProxy;
import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapController;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ItemizedIconOverlay;
import org.osmdroid.views.overlay.ItemizedOverlay;
import org.osmdroid.views.overlay.OverlayItem;
import org.osmdroid.views.util.constants.MapViewConstants;

import android.app.Activity;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;

public class DemoMap extends Activity implements LocationListener,
        MapViewConstants {

    private MapView mMapView;
    private MapController mapController;
    private LocationManager mLocMgr;
    private ItemizedOverlay<OverlayItem> mMyLocationOverlay;
    private ResourceProxy mResourceProxy;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());
        setContentView(R.layout.copymain);

        mMapView = (MapView) this.findViewById(R.id.mapview);
        mMapView.setTileSource(TileSourceFactory.MAPNIK);
        mMapView.setBuiltInZoomControls(true);
        mMapView.setMultiTouchControls(true);
        mapController = this.mMapView.getController();
        mapController.setZoom(15);
        GeoPoint point2 = new GeoPoint(53554070, -2959520); // centre map here
        GeoPoint point3 = new GeoPoint(53554070 + 1000, -2959520 + 1000); // icon goes here
        mapController.setCenter(point2);
        mLocMgr = (LocationManager) getSystemService(LOCATION_SERVICE);
        mLocMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 100,
                this);

        ArrayList<OverlayItem> items = new ArrayList<OverlayItem>();
        // Put overlay icon a little way from map centre
        items.add(new OverlayItem("Here", "SampleDescription", point3));

        /* OnTapListener for the Markers, shows a simple Toast. */
        this.mMyLocationOverlay = new ItemizedIconOverlay<OverlayItem>(items,
                new ItemizedIconOverlay.OnItemGestureListener<OverlayItem>() {
                    @Override
                    public boolean onItemSingleTapUp(final int index,
                            final OverlayItem item) {
                        Toast.makeText(
                                DemoMap.this,
                                "Item '" + item.mTitle, Toast.LENGTH_LONG).show();
                        return true; // We 'handled' this event.
                    }
                    @Override
                    public boolean onItemLongPress(final int index,
                            final OverlayItem item) {
                        Toast.makeText(
                                DemoMap.this, 
                                "Item '" + item.mTitle ,Toast.LENGTH_LONG).show();
                        return false;
                    }
                }, mResourceProxy);
        this.mMapView.getOverlays().add(this.mMyLocationOverlay);
        mMapView.invalidate();
    }

    public void onLocationChanged(Location location) {
        int lat = (int) (location.getLatitude() * 1E6);
        int lng = (int) (location.getLongitude() * 1E6);
        GeoPoint gpt = new GeoPoint(lat, lng);
        mapController.setCenter(gpt);
        mMapView.invalidate();
    }

    @Override
    public void onProviderDisabled(String arg0) {}
    @Override
    public void onProviderEnabled(String provider) {}
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {}

}

It's a bit rough and ready, but at least it runs OK with just the 3.0.4 jar and the slf4j one. Hope it helps.

EDIT 2

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="osmdemo.demo"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name="DemoMap"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="3" />

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> 
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

</manifest> 

.

回答2:

If you are trying to add an icon, then you want to look at the ItemizedOverlay classes. You can use osmdroid's ItemizedIconOverlay which is a concrete implementation of ItemizedOverlay, or you can subclass ItemizedOverlay on your own. Take a look at the samples, such as:

http://code.google.com/p/osmdroid/source/browse/trunk/OpenStreetMapViewer/src/org/osmdroid/samples/SampleWithMinimapItemizedoverlay.java

回答3:

@rayman

Please one more thing. When there is a change in the location the map does change but the Icon is gone. how do i validate the Icon into the new change? – rayman Jul 1 '11 at 7:12

this is where your location changes

public void onLocationChanged(Location location) {
    int lat = (int) (location.getLatitude() * 1E6);
    int lng = (int) (location.getLongitude() * 1E6);
    GeoPoint gpt = new GeoPoint(lat, lng);
    mapController.setCenter(gpt);
    mMapView.invalidate();
}

But as you can see it does not add new icon to the overlay.

You should clear the previous items

items.clear()

(if you want the "old" icon to be removed when the new one is created) and then add the new point (gpt) to the items.

items.add(new OverlayItem("Title", "Description", gpt));

and so on...