我正在尝试向 OSMDroid map 添加路径叠加层,但它没有出现。我错过了什么?
更新:
我发现它与图 block 大小有关。我将大小设置为 512,即使图 block 为 256,否则 map 太小而无法在高像素密度屏幕上阅读。如果我将大小更改为 256,则会显示路径。如果我将它改回 512,它不会显示。
public class MainActivity extends Activity {
// set this to 256 for actual tile size, 512 to show larger and cause PathOverlay to not be displayed
int tileSize = 512;
private MapView mapView;
// area of offline tiles
double north = 40.739063;
double south = 40.708361;
double west = -73.967171;
double east = -73.936272;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// center of offline tiles
double centerlat = (double) ((north+south)/2);
double centerlon = (double) ((west+east)/2);
// copy tiles to sd location for offline map
putMapOnSD();
// create mapView and show layout
mapView = new MapView(this,tileSize);
final LinearLayout layout = new LinearLayout(this);
final LinearLayout.LayoutParams mapViewLayoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT);
layout.addView(mapView, mapViewLayoutParams);
setContentView(layout);
// set map to use offline tiles and display
mapView.setTileSource (new XYTileSource ("tiles", ResourceProxy.string.offline_mode, 13, 17, tileSize, ".png", "http://127.0.0.1"));
mapView.setUseDataConnection(false);
mapView.setClickable(false);
mapView.setMultiTouchControls(true);
mapView.setBuiltInZoomControls(false);
mapView.getController().setZoom(15);
mapView.getController().setCenter(new GeoPoint(centerlat,centerlon));
// show pathOverlay
PathOverlay pathOverlay = new PathOverlay(Color.RED, this);
pathOverlay.addPoint(new GeoPoint(centerlat,centerlon));
centerlat += 0.005;
pathOverlay.addPoint(new GeoPoint(centerlat,centerlon));
centerlon += 0.005;
pathOverlay.addPoint(new GeoPoint(centerlat,centerlon));
pathOverlay.getPaint().setStrokeWidth(10.0f);
mapView.getOverlays().add(pathOverlay);
// refresh map, is this needed?
mapView.invalidate();
}
// this copies the offline tiles to the proper location for OSMDroid to use them offline
private void putMapOnSD() {
// see GitHub for this
}
}
在 GitHub 上获取完整项目。 https://github.com/tomkincaid/PathExample
我通过使用 Cloudmade 的 @2x tiles 解决了这个问题,所以我不必为高密度屏幕使用 512 像素大小。基本问题仍然存在,以防万一有人想调查。
最佳答案
尝试在 PathOverlay
中添加带有描边的 Paint
。
Paint paint = new Paint();
paint.setAlpha(155);
paint.setColor(Color.argb(205, 178, 255, 255));
paint.setStyle(Style.STROKE);
paint.setStrokeWidth(10);
pathOverlay.setPaint(paint);
更新:
我认为,您的路径未出现的主要原因与 Tile Size
参数直接相关。因为在绘制pathOVerlay的时候,所有的投影和直线计算都是基于这个参数。因此,如果您将其设置为不是图 block 实际大小的值,则计算将失败并且不会显示覆盖路径。
关于android - OSMDroid PathOverlay 没有出现,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19776760/