攝即是空

public void listf(String directoryName, ArrayList<File> files) {
File directory = new File(directoryName);

// get all the files from a directory
File[] fList = directory.listFiles();
for (File file : fList) {
if (file.isFile()) {
files.add(file);
} else if (file.isDirectory()) {
listf(file.getAbsolutePath(), files);
}
}
}

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

http://stackoverflow.com/questions/8638293/how-to-list-all-files-and-folders-locating-on-sd-card