我们刚刚开始在 Android 上使用 Google 地图，并设置了一个 GeoServer 来提供我们希望添加为地图上的叠加层的图块。到目前为止，我已经按照一些教程和参考资料开始学习。
问题：虽然当我设置断点并将 url 复制并粘贴到浏览器中时，我在getTileUrl函数中生成的 urlTileProviderFactory确实返回了 png 图像，但它不会作为 Android 设备上的叠加层加载到地图上. 从我所看到的内容中没有抛出任何错误，在阅读完这篇文章后，我不确定是否会有任何错误，因为他们已经表明错误正在被忽略。
我想知道的是，您是否可以在我的代码中看到任何直接问题，或者对调试有任何建议，我将能够判断应用程序是否实际上正在与我的 GeoServer 通信以检索图像。我查看了 GeoServer 上的日志，似乎只有我的浏览器请求正在通过，并且没有收到来自 Android 的任何请求（这有点难以分辨，因为我们还有其他应用程序也在使用该服务器）。Android手机通过wifi和手机连接，并启用了gps。作为最后的手段，我尝试更改平铺覆盖 zIndex 并将其设置为可见，但这似乎没有任何区别。
编辑：Android 设备此时绝对没有与 GeoServer 通信。
编辑2：能够从网站（如this）加载静态图像作为覆盖，并发现我在测试对形成的URL的HTTP请求时遇到以下异常：
W/System.err(10601): java.net.SocketException: The operation timed out
W/System.err(10601): at org.apache.harmony.luni.platform.OSNetworkSystem
.connectStreamWithTimeoutSocketImpl(Native Method)
W/System.err(10601): at org.apache.harmony.luni.net.PlainSocketImpl
.connect(PlainSocketImpl.java:244)
W/System.err(10601): at org.apache.harmony.luni.net.PlainSocketImpl
.connect(PlainSocketImpl.java:533)
W/System.err(10601): at java.net.Socket
.connect(Socket.java:1074)
W/System.err(10601): at org.apache.http.conn.scheme.PlainSocketFactory
.connectSocket(PlainSocketFactory.java:119)
谢谢。
地图测试活动
public class MapTestActivity extends FragmentActivity
implements LocationListener, LocationSource{
private GoogleMap mMap;
private OnLocationChangedListener mListener;
private LocationManager locationManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map_test);
setupLocationManager();
setupMapIfNeeded();
}
private void setupLocationManager() {
this.locationManager =
(LocationManager) getSystemService(LOCATION_SERVICE);
if (locationManager != null) {
boolean gpsIsEnabled = locationManager.isProviderEnabled(
LocationManager.GPS_PROVIDER);
boolean networkIsEnabled = locationManager.isProviderEnabled(
LocationManager.NETWORK_PROVIDER);
if(gpsIsEnabled) {
this.locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 5000L, 10F, this);
}
else if(networkIsEnabled) {
this.locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, 5000L, 10F, this);
}
else {
//Show an error dialog that GPS is disabled...
}
}
else {
// Show some generic error dialog because
// something must have gone wrong with location manager.
}
}
private void setupMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the
// map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map)).getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
mMap.setLocationSource(this);
}
}
private void setUpMap() {
// TODO Auto-generated method stub
mMap.setMyLocationEnabled(true);
TileProvider geoServerTileProvider = TileProviderFactory
.getGeoServerTileProvider();
TileOverlay geoServerTileOverlay = mMap.addTileOverlay(
new TileOverlayOptions()
.tileProvider(geoServerTileProvider)
.zIndex(10000)
.visible(true));
}
// Non-relevant listener methods removed
}
TileProviderFactory
public class TileProviderFactory {
public static GeoServerTileProvider getGeoServerTileProvider() {
String baseURL = "mytileserver.com";
String version = "1.3.0";
String request = "GetMap";
String format = "image/png";
String srs = "EPSG:900913";
String service = "WMS";
String width = "256";
String height = "256";
String styles = "";
String layers = "wtx:road_hazards";
final String URL_STRING = baseURL +
"&LAYERS=" + layers +
"&VERSION=" + version +
"&SERVICE=" + service +
"&REQUEST=" + request +
"&TRANSPARENT=TRUE&STYLES=" + styles +
"&FORMAT=" + format +
"&SRS=" + srs +
"&BBOX=%f,%f,%f,%f" +
"&WIDTH=" + width +
"&HEIGHT=" + height;
GeoServerTileProvider tileProvider =
new GeoServerTileProvider(256,256) {
@Override
public synchronized URL getTileUrl(int x, int y, int zoom) {
try {
double[] bbox = getBoundingBox(x, y, zoom);
String s = String.format(Locale.US, URL_STRING, bbox[MINX],
bbox[MINY], bbox[MAXX], bbox[MAXY]);
Log.d("GeoServerTileURL", s);
URL url = null;
try {
url = new URL(s);
}
catch (MalformedURLException e) {
throw new AssertionError(e);
}
return url;
}
catch (RuntimeException e) {
Log.d("GeoServerTileException",
"getTile x=" + x + ", y=" + y +
", zoomLevel=" + zoom +
" raised an exception", e);
throw e;
}
}
};
return tileProvider;
}
}
GeoServerTileProvider
public abstract class GeoServerTileProvider extends UrlTileProvider{
// Web Mercator n/w corner of the map.
private static final double[] TILE_ORIGIN =
{-20037508.34789244, 20037508.34789244};
//array indexes for that data
private static final int ORIG_X = 0;
private static final int ORIG_Y = 1; // "
// Size of square world map in meters, using WebMerc projection.
private static final double MAP_SIZE = 20037508.34789244 * 2;
// array indexes for array to hold bounding boxes.
protected static final int MINX = 0;
protected static final int MINY = 1;
protected static final int MAXX = 2;
protected static final int MAXY = 3;
public GeoServerTileProvider(int width, int height) {
super(width, height);
}
// Return a web Mercator bounding box given tile x/y indexes and a zoom
// level.
protected double[] getBoundingBox(int x, int y, int zoom) {
double tileSize = MAP_SIZE / Math.pow(2, zoom);
double minx = TILE_ORIGIN[ORIG_X] + x * tileSize;
double maxx = TILE_ORIGIN[ORIG_X] + (x+1) * tileSize;
double miny = TILE_ORIGIN[ORIG_Y] - (y+1) * tileSize;
double maxy = TILE_ORIGIN[ORIG_Y] - y * tileSize;
double[] bbox = new double[4];
bbox[MINX] = minx;
bbox[MINY] = miny;
bbox[MAXX] = maxx;
bbox[MAXY] = maxy;
return bbox;
}
}