最近Android吧在做个功能是将asset文件夹下的所有文件（包括子文件）全部拷贝出来到指定目录下。所用的方法无非是用AssetManager。但是这里有个问题是也要讲子文件夹和子文件都要拷贝出来。到网上Google了下，也到baidu搜索了下，发现了很多类似问题。但好像都有问题。有些显然只能做到将asset直接目录下的文件拷贝出来，但子文件夹拷贝不出来，而且，碰到文件夹，会抛异常。无奈自己只好动手写了个。如下：
private void CopyAssets(String assetDir, String dir) { String[] files; try { files = this.getResources().getAssets().list(assetDir); } catch (IOException e1) { return; } File mWorkingPath = new File(dir); // if this directory does not exists, make one. if (!mWorkingPath.exists()) { if (!mWorkingPath.mkdirs()) { } } for (int i = 0; i < files.length; i++) { try { String fileName = files[i]; // we make sure file name not contains '.' to be a folder. if (!fileName.contains(".")) { if (0 == assetDir.length()) { CopyAssets(fileName, dir + fileName + "/"); } else { CopyAssets(assetDir + "/" + fileName, dir + fileName + "/"); } continue; } File outFile = new File(mWorkingPath, fileName); if (outFile.exists()) outFile.delete(); InputStream in = null; if (0 != assetDir.length()) { in = getAssets().open(assetDir + "/" + fileName); } else { in = getAssets().open(fileName); } OutputStream out = new FileOutputStream(outFile); // Transfer bytes from in to out byte[] buf = new byte[1024]; int len; while ((len = in.read(buf)) > 0) { out.write(buf, 0, len); } } catch (Exception e) { e.printStackTrace(); } } }非原创，原文出处： http://tieba.baidu.com/f?kz=1096393066