osmdroid API解读（六）

osmdroid-android org.osmdroid.tileprovider.cachemanager 包

1. CacheManager

提供了一系列的管理瓦片在本地的缓存:

• 下载瓦片到特定的区域
• 清除特定区域的瓦片
• 缓存容量信息及当前缓存的使用

注意：这些方法仅用于使用OnlineTileSourceBase瓦片源的MapView。

public class CacheManager {    protected final ITileSource mTileSource;    protected final IFilesystemCache mTileWriter;    protected final int mMinZoomLevel;    protected final int mMaxZoomLevel;    protected Set<CacheManagerTask> mPendingTasks = new HashSet<>();    protected boolean verifyCancel = true;    ...}

osmdroid-android org.osmdroid.tileprovider.utils包

1. ManifestUtil

用于读取Manifest的工具，目前仅有用于根据key查询meta数据的方法，用于在线地图的注册验证

public class ManifestUtil {    public static String retrieveKey(final Context aContext, final String aKey) {        // get the key from the manifest        final PackageManager pm = aContext.getPackageManager();        try {            final ApplicationInfo info = pm.getApplicationInfo(aContext.getPackageName(),                    PackageManager.GET_META_DATA);            if (info.metaData == null) {                Log.i(IMapView.LOGTAG,"Key %s not found in manifest"+aKey);            } else {                final String value = info.metaData.getString(aKey);                if (value == null) {                    Log.i(IMapView.LOGTAG,"Key %s not found in manifest"+aKey);                } else {                    return value.trim();                }            }        } catch (final PackageManager.NameNotFoundException e) {            Log.i(IMapView.LOGTAG,"Key %s not found in manifest" +aKey);        }        return "";    }}

2. Counters

自定义的一些用于追踪内部不同问题或错误的容器，用于解决osmdroid解决问题、发现内存泄漏等

public class Counters {    static final String TAG="osmCounters";    //out of memory errors    public static int countOOM =0;    public static int tileDownloadErrors=0;    public static int fileCacheSaveErrors=0;    public static int fileCacheMiss=0;    public static int fileCacheOOM=0;    public static int fileCacheHit=0;    public static void printToLogcat() {        Log.d(TAG, "countOOM " + countOOM);        Log.d(TAG, "tileDownloadErrors " + tileDownloadErrors);        Log.d(TAG, "fileCacheSaveErrors " + fileCacheSaveErrors);        Log.d(TAG, "fileCacheMiss " + fileCacheMiss);        Log.d(TAG, "fileCacheOOM " + fileCacheOOM);        Log.d(TAG, "fileCacheHit " + fileCacheHit);    }    public static void reset(){        countOOM =0;        tileDownloadErrors=0;        fileCacheSaveErrors=0;        fileCacheMiss=0;        fileCacheOOM=0;        fileCacheHit=0;    }}

2. SimpleInvalidationHandler

一个简单的Handler类

public class SimpleInvalidationHandler extends Handler {    private View mView;    public SimpleInvalidationHandler(final View pView) {        super();        mView = pView;    }    @Override    public void handleMessage(final Message msg) {        switch (msg.what) {        case MapTile.MAPTILE_SUCCESS_ID:            if (mView!=null)                mView.invalidate();            break;        }    }    /**     * See <a href="https://github.com/osmdroid/osmdroid/issues/390">https://github.com/osmdroid/osmdroid/issues/390</a>     *     */    public void destroy(){        mView=null;    }}

3. SimpleRegisterReceiver

一个简单的注册接收者，用于接收广播

public class SimpleRegisterReceiver implements IRegisterReceiver {    private Context mContext;    public SimpleRegisterReceiver(final Context pContext) {        super();        mContext = pContext;    }    @Override    public Intent registerReceiver(final BroadcastReceiver aReceiver, final IntentFilter aFilter) {        return mContext.registerReceiver(aReceiver, aFilter);    }    @Override    public void unregisterReceiver(final BroadcastReceiver aReceiver) {        mContext.unregisterReceiver(aReceiver);    }    @Override    public void destroy() {        mContext=null;    }}

4. StorageUtils

用于管理本地内存访问、管理的类

public class StorageUtils {    ...}

5. StreamUtils

用于流访问、管理的工具

public class StreamUtils {    ...}

6. CloudmadeUtil

云端访问和管理的工具

public class CloudmadeUtil{    ...}