为 OSMDROID 添加叠加层

Question

我已经挣扎了这么长时间了。 我正在尝试在我的地图上添加叠加。 我正在使用开源 OSMdroid。但我通过这个例子得到的只是一条从一个角到另一个角的直线红线。 我的目标是在设置我的 geoPoint 的位置添加一些图标。

这是我的代码：

 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)
        {
        }

    }

}

那就是我的清单：

<?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>

提前致谢，

雷。

Answer 1

如果您尝试添加图标，那么您需要查看 ItemizedOverlay 类。您可以使用 osmdroid 的 ItemizedIconOverlay，它是 ItemizedOverlay 的具体实现，或者您可以自己创建 ItemizedOverlay 的子类。查看示例，例如：

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

Answer 2

@雷曼

请再说一件事。当地图位置发生变化时
确实改变了，但图标消失了。我如何验证图标
新变化？ – 雷曼 2011 年 7 月 1 日 7:12

这是您的位置发生变化的地方

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();
}

，但正如您所看到的，它不会向叠加层添加新图标。

您应该清除以前的项目

items.clear()

（如果您希望在创建新项目时删除“旧”图标），然后将新点 (gpt) 添加到项目中。

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

等等...

Answer 3

自示例代码编写以来，jar 版本 3.0.3 和 3.0.4 似乎发生了一些变化。

如果您的应用程序基于上一个答案中引用的代码，则将该行更改

mResourceProxy = new ResourceProxyImpl(getApplicationContext());

为

mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());

“这至少应该让您使用默认图标”。

编辑

这应该将地图置于利物浦东北部的中心，并在偏离中心的位置放置一个图标。

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) {}

}

它有点粗糙，但至少只用 3.0.4 jar 和 slf4j 就可以运行了。希望有帮助。

编辑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> 

。