硬件存储工具类
也就是管理我们的缓存文件在手机硬件上存储的位置
如果我们以后要做本地缓存文件的话，可以直接拷贝该文件，简单的修改一下目录名称，即可。
源码:
/** * Provides application storage paths * * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) * @since 1.0.0 */ public final class StorageUtils { private static final String EXTERNAL_STORAGE_PERMISSION = "android.permission.WRITE_EXTERNAL_STORAGE"; private static final String INDIVIDUAL_DIR_NAME = "uil-images"; private StorageUtils() { } /** * Returns application cache directory. Cache directory will be created on SD card * <i>("/Android/data/[app_package_name]/cache")</i> if card is mounted and app has appropriate permission. Else - * Android defines cache directory on device's file system. * * @param context Application context * @return Cache {@link File directory}.<br /> * <b>NOTE:</b> Can be null in some unpredictable cases (if SD card is unmounted and * {@link android.content.Context#getCacheDir() Context.getCacheDir()} returns null). */ public static File getCacheDirectory(Context context) { return getCacheDirectory(context, true); } /** * Returns application cache directory. Cache directory will be created on SD card * <i>("/Android/data/[app_package_name]/cache")</i> (if card is mounted and app has appropriate permission) or * on device's file system depending incoming parameters. * * @param context Application context * @param preferExternal Whether prefer external location for cache * @return Cache {@link File directory}.<br /> * <b>NOTE:</b> Can be null in some unpredictable cases (if SD card is unmounted and * {@link android.content.Context#getCacheDir() Context.getCacheDir()} returns null). */ public static File getCacheDirectory(Context context, boolean preferExternal) { File appCacheDir = null; String externalStorageState; try { externalStorageState = Environment.getExternalStorageState(); } catch (NullPointerException e) { // (sh)it happens (Issue #660) externalStorageState = ""; } catch (IncompatibleClassChangeError e) { // (sh)it happens too (Issue #989) externalStorageState = ""; } if (preferExternal && MEDIA_MOUNTED.equals(externalStorageState) && hasExternalStoragePermission(context)) { appCacheDir = getExternalCacheDir(context);//在外部sd卡上分配缓存空间 } if (appCacheDir == null) { appCacheDir = context.getCacheDir();//系统提供的缓存空间 } if (appCacheDir == null) {//自己创建缓存目录 String cacheDirPath = "/data/data/" + context.getPackageName() + "/cache/"; L.w("Can't define system cache directory! '%s' will be used.", cacheDirPath); appCacheDir = new File(cacheDirPath); } return appCacheDir; } /** * Returns individual application cache directory (for only image caching from ImageLoader). Cache directory will be * created on SD card <i>("/Android/data/[app_package_name]/cache/uil-images")</i> if card is mounted and app has * appropriate permission. Else - Android defines cache directory on device's file system. * * @param context Application context * @return Cache {@link File directory} */ public static File getIndividualCacheDirectory(Context context) { return getIndividualCacheDirectory(context, INDIVIDUAL_DIR_NAME); } /** * Returns individual application cache directory (for only image caching from ImageLoader). Cache directory will be * created on SD card <i>("/Android/data/[app_package_name]/cache/uil-images")</i> if card is mounted and app has * appropriate permission. Else - Android defines cache directory on device's file system. * * @param context Application context * @param cacheDir Cache directory path (e.g.: "AppCacheDir", "AppDir/cache/images") * @return Cache {@link File directory} */ public static File getIndividualCacheDirectory(Context context, String cacheDir) {//在获取到的缓存目录中创建独立的特定目录 File appCacheDir = getCacheDirectory(context); File individualCacheDir = new File(appCacheDir, cacheDir); if (!individualCacheDir.exists()) { if (!individualCacheDir.mkdir()) { individualCacheDir = appCacheDir; } } return individualCacheDir; } /** * Returns specified application cache directory. Cache directory will be created on SD card by defined path if card * is mounted and app has appropriate permission. Else - Android defines cache directory on device's file system. * * @param context Application context * @param cacheDir Cache directory path (e.g.: "AppCacheDir", "AppDir/cache/images") * @return Cache {@link File directory} */ public static File getOwnCacheDirectory(Context context, String cacheDir) {//获取应用的缓存 File appCacheDir = null; if (MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) && hasExternalStoragePermission(context)) { appCacheDir = new File(Environment.getExternalStorageDirectory(), cacheDir); } if (appCacheDir == null || (!appCacheDir.exists() && !appCacheDir.mkdirs())) { appCacheDir = context.getCacheDir(); } return appCacheDir; } /** * Returns specified application cache directory. Cache directory will be created on SD card by defined path if card * is mounted and app has appropriate permission. Else - Android defines cache directory on device's file system. * * @param context Application context * @param cacheDir Cache directory path (e.g.: "AppCacheDir", "AppDir/cache/images") * @return Cache {@link File directory} */ public static File getOwnCacheDirectory(Context context, String cacheDir, boolean preferExternal) { File appCacheDir = null; if (preferExternal && MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) && hasExternalStoragePermission(context)) { appCacheDir = new File(Environment.getExternalStorageDirectory(), cacheDir); } if (appCacheDir == null || (!appCacheDir.exists() && !appCacheDir.mkdirs())) { appCacheDir = context.getCacheDir(); } return appCacheDir; } private static File getExternalCacheDir(Context context) {// android/data/{package}/cache File dataDir = new File(new File(Environment.getExternalStorageDirectory(), "Android"), "data"); File appCacheDir = new File(new File(dataDir, context.getPackageName()), "cache"); if (!appCacheDir.exists()) { if (!appCacheDir.mkdirs()) { L.w("Unable to create external cache directory"); return null; } try { new File(appCacheDir, ".nomedia").createNewFile(); } catch (IOException e) { L.i("Can't create \".nomedia\" file in application external cache directory"); } } return appCacheDir; } private static boolean hasExternalStoragePermission(Context context) {//是否有外部存储的访问权限 int perm = context.checkCallingOrSelfPermission(EXTERNAL_STORAGE_PERMISSION); return perm == PackageManager.PERMISSION_GRANTED; } }