用OSMDroid載入Google地圖的時候 需要有按鈕切換不同圖層的地圖，如果發現呼叫了mMapView.setTileSource(ITileSource aTileSource)方法的時候發現地圖View沒有更新的話，可能是因為兩個例項化TileSource物件其子類BitmapTileSourceBase這個類的aName成員變數值一樣導致的地圖在setTileSource出現不更新問題，只要在new XYTileSource的時候構造器的aName在不同的例項化物件中設定為不同的name就好了，望大家注意這點。

package org.osmdroid.tileprovider.tilesource;

import org.osmdroid.util.MapTileIndex;

public class XYTileSource extends OnlineTileSourceBase {
    public XYTileSource(String aName, int aZoomMinLevel, int aZoomMaxLevel, int aTileSizePixels, String aImageFilenameEnding, String[] aBaseUrl) {
        this(aName, aZoomMinLevel, aZoomMaxLevel, aTileSizePixels, aImageFilenameEnding, aBaseUrl, (String)null);
    }

    public XYTileSource(String aName, int aZoomMinLevel, int aZoomMaxLevel, int aTileSizePixels, String aImageFilenameEnding, String[] aBaseUrl, String copyright) {
        super(aName, aZoomMinLevel, aZoomMaxLevel, aTileSizePixels, aImageFilenameEnding, aBaseUrl, copyright);
    }

    public String toString() {
        return this.name();
    }

    public String getTileURLString(long pMapTileIndex) {
        return this.getBaseUrl() + MapTileIndex.getZoom(pMapTileIndex) + "/" + MapTileIndex.getX(pMapTileIndex) + "/" + MapTileIndex.getY(pMapTileIndex) + this.mImageFilenameEnding;
    }
}