如何利用LRUCache製作安卓端谷歌地圖的三級快取
阿新 • • 發佈:2018-12-12
第一個檔案,繼承ArcGIS的TileServerLayer
/** * * @author wjf * @date 2018/09/30 */ public class GoogleMapLayer extends TiledServiceLayer { private static final int MAXLRU_SIZE=1024*1024*8*1;//假設為1M; private final int MIN_LEVEL = 0;//設定縮放的最小級別 private final int MAX_LEVEL = 19;//設定縮放的最大級別,這裡最大層級19,可以自定義(需要在下方的 MAP_SCALE 和 RESOLUTIONS 中設定相對應的資料) private int GoogleMapLayerType; private MapCacheHelper cacheHelper; private double[] MAP_SCALE = new double[]{591657527.591555, 295828763.79577702, 147914381.89788899, 73957190.948944002, 36978595.474472001, 18489297.737236001, 9244648.8686180003, 4622324.4343090001, 2311162.217155, 1155581.108577, 577790.554289, 288895.277144, 144447.638572, 72223.819286, 36111.909643, 18055.954822, 9027.9774109999998, 4513.9887049999998, 2256.994353, 1128.4971760000001}; private double[] RESOLUTIONS = new double[]{156543.03392800014, 78271.516963999937, 39135.758482000092, 19567.879240999919, 9783.9396204999593, 4891.9698102499797, 2445.9849051249898, 1222.9924525624949, 611.49622628138, 305.748113140558, 152.874056570411, 76.4370282850732, 38.2185141425366, 19.1092570712683, 9.55462853563415, 4.7773142679493699, 2.3886571339746849, 1.1943285668550503, 0.59716428355981721, 0.29858214164761665}; private Point ORIGIN_PNT = new Point(-20037508.342787, 20037508.342787); private int DPI = 96; private int TILEWIDTH = 256; private int TILEHEIGHT = 256; public GoogleMapLayer(int layerType) { super(true); this.GoogleMapLayerType = layerType; this.init(); } private void init() { try { getServiceExecutor().submit(() -> GoogleMapLayer.this.initLayer()); // 這裡是設定快取到本地的路徑 可以自定義 String imgPtPath = AppConsts.CACHE_DIR + "/t" + GoogleMapLayerType + "/"; cacheHelper=new MapCacheHelper(GoogleMapLayerType,MAXLRU_SIZE,imgPtPath); } catch (RejectedExecutionException rejectedexecutionexception) { Log.e("Google Map Layer", "initialization of the layer failed.", rejectedexecutionexception); } } @Override protected byte[] getTile(int level, int col, int row) throws Exception { byte[] res; if (level > MAX_LEVEL || level < MIN_LEVEL) { return new byte[0]; } String s = "Galileo".substring(0, ((3 * col + row) % 8)); String url = getMapUrl(level,col,row,s); //開始獲取三級快取1、記憶體 if((res=cacheHelper.getMapCache(url))!=null){ return res; }else if((res=cacheHelper.getLocalMapCache(level,col,row))!=null){ cacheHelper.setMapCache(url,res); return res; }else{ if (isNetworkAvailable(MyApp.getContext())) { Map<String, String> map = null; res= com.esri.core.internal.io.handler.a.a(url, map); cacheHelper.setLocalMapCache(level,col,row,res); cacheHelper.setMapCache(url,res); return res; }else{ } } return new byte[0]; } protected SpatialReference getSptialReference() { return this.getDefaultSpatialReference(); } @Override protected void initLayer() { if (getID() == 0L) { nativeHandle = create(); changeStatus(com.esri.android.map.event.OnStatusChangedListener.STATUS.fromInt(-1000)); } else { this.setDefaultSpatialReference(SpatialReference.create(102113)); this.setFullExtent(new Envelope(-20037508.34, -20037508.34, 20037508.34, 20037508.34)); this.setTileInfo(new TileInfo(ORIGIN_PNT, MAP_SCALE, RESOLUTIONS, MAP_SCALE.length, DPI, TILEWIDTH, TILEHEIGHT)); super.initLayer(); } } private boolean isNetworkAvailable(Context context) { ConnectivityManager manager = (ConnectivityManager) context.getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE); if (manager == null) { return false; } NetworkInfo networkinfo = manager.getActiveNetworkInfo(); if (networkinfo == null || !networkinfo.isAvailable()) { return false; } return true; } public String getMapUrl(int level, int col, int row,String s){ String url=""; switch (GoogleMapLayerType) { case GoogleMapLayerTypes.IMAGE_GOOGLE_MAP: url = "http://mt" + (col % 4) + ".google.cn/vt/lyrs=s&hl=zh-CN&gl=cn&" + "x=" + col + "&" + "y=" + row + "&" + "z=" + level + "&" + "s=" + s; break; case GoogleMapLayerTypes.VECTOR_GOOGLE_MAP: url = "http://mt2.google.cn/vt/[email protected]&hl=zh-CN&gl=cn&" + "x=" + col + "&" + "y=" + row + "&" + "z=" + level + "&" + "s=" + s; break; case GoogleMapLayerTypes.TERRAIN_GOOGLE_MAP: url = "http://mt" + (col % 4) + ".google.cn/vt/[email protected],[email protected]&hl=zh-CN&gl=cn&" + "x=" + col + "&" + "y=" + row + "&" + "z=" + level + "&" + "s=" + s; break; case GoogleMapLayerTypes.ANNOTATION_GOOGLE_MAP: url = "http://mt" + (col % 4) + ".google.cn/vt/imgtp=png32&[email protected]&hl=zh-CN&gl=cn&" + "x=" + col + "&" + "y=" + row + "&" + "z=" + level + "&" + "s=" + s; break; } return url; } }
第二個檔案:
public interface GoogleMapLayerTypes { /** * 谷歌向量地圖服務 */ int VECTOR_GOOGLE_MAP = 1; /** * 谷歌影像地圖服務 */ int IMAGE_GOOGLE_MAP = 2; /** * 谷歌地形地圖服務 */ int TERRAIN_GOOGLE_MAP = 3; /** * 谷歌道路等POI地圖服務 */ int ANNOTATION_GOOGLE_MAP = 4; } 第三個檔案 實現快取
** * @author:wjf * @date:20180930 * 為谷歌地圖配置相對應的 */ public class MapCacheHelper { private int GoogleMapLayerType; LruCache<String,byte[]> myLruCache; String filePath; /** * * @param googleMapLayerType 地圖型別 * @param mapLRUCapacity LRUCache的大小 * @param filePath 存放本地快取的路徑 */ public MapCacheHelper(int googleMapLayerType, int mapLRUCapacity, String filePath){ this.GoogleMapLayerType=googleMapLayerType; this.filePath=filePath; FileUtils.createDirs(filePath); myLruCache=new LruCache<String,byte[]>(mapLRUCapacity){ @Override protected int sizeOf(String key, byte[] value) { return value.length; } }; } public byte[] getMapCache(String url){ return myLruCache.get(url); } public void setMapCache(String url,byte[] data){ myLruCache.put(url,data); } private byte[] getLocalMapCache(String imgPath,String imgName){ Bitmap bitmap = BitmapFactory.decodeFile(imgPath + imgName); if(bitmap==null) return null; ByteArrayOutputStream baos = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos); return baos.toByteArray(); } public byte[] getLocalMapCache(int level, int col, int row){ String imgPath = filePath+ "l" + level + "/"; String imgName = "c" + col + "r" + row + ".png"; return getLocalMapCache(imgPath,imgName); } private void saveFile(String filePath, byte[] data, String fileName) throws IOException { Bitmap mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);// bitmap File dirFile = new File(filePath); if (!dirFile.exists()) { dirFile.mkdir(); } // 檢測是否有 .nomedia 檔案,該檔案防止相簿等媒體軟體掃描離線地圖圖片,以免造成不必要的麻煩 File nomediaFile = new File(filePath + ".nomedia"); if (!nomediaFile.exists()) { nomediaFile.createNewFile(); } File myCaptureFile = new File(filePath + fileName); // 判斷離線的圖片是否已經存在,已經存在的地圖不用再次下載(節省流量) if (myCaptureFile.exists()) { return; } BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(myCaptureFile)); mBitmap.compress(Bitmap.CompressFormat.PNG, 80, bos); bos.flush(); bos.close(); } public void setLocalMapCache(int level, int col, int row, byte[] data){ try { String imgPath = filePath+ "l" + level + "/"; String imgName = "c" + col + "r" + row + ".png"; saveFile(imgPath,data, imgName); } catch (IOException e) { e.printStackTrace(); } } }