如何查询以选择Android中特定文件夹中的所有文件？

试试这个

ArrayList<File> mFiles = new ArrayList<File>();
          File mDirectory;
         String folderPath = "/mnt/sdcard/download";
         mDirectory = new File(folderPath);
         ExtensionFilenameFilter filter = new ExtensionFilenameFilter(acceptedFileExtensions);

            // Get the files in the directory
            File[] files = mDirectory.listFiles(filter);
            if (files != null && files.length > 0) {
                for (File f : files) {

                    mFiles.add(f);
                }

                Collections.sort(mFiles, new FileComparator());
            }