List all the files from all the folders in a single list

Question

I am looking for the solution to list all the files from root/Android device.

Suppose there are three folders inside the root directory, but I want to display all the files in all of these folders in a single list...

Now if am using

File f = new File("/sdcard");

Then it will list all the files from the sdcard folder only... And if I will use

File f = new File("/download");

Then it will list all the files from download folder only ..and if I will use

File f = new File("/");

Then it will list only the root directory files...not the files inside /sdcard or /download.

So what steps shall I follow to list all the files with a filter to list only .csv files from all the folder inside root?

Answer 1

Try this:

 .....
 List<File> files = getListFiles(new File("YOUR ROOT"));
 ....
 private List<File> getListFiles(File parentDir) {
    ArrayList<File> inFiles = new ArrayList<File>();
    File[] files = parentDir.listFiles();
    for (File file : files) {
        if (file.isDirectory()) {
            inFiles.addAll(getListFiles(file));
        } else {
            if(file.getName().endsWith(".csv")) {
                inFiles.add(file);
            }
        }
    }
    return inFiles;
}

Or a variant without recursion:

private List<File> getListFiles2(File parentDir) {
    List<File> inFiles = new ArrayList<>();
    Queue<File> files = new LinkedList<>();
    files.addAll(Arrays.asList(parentDir.listFiles()));
    while (!files.isEmpty()) {
        File file = files.remove();
        if (file.isDirectory()) {
            files.addAll(Arrays.asList(file.listFiles()));
        } else if (file.getName().endsWith(".csv")) {
            inFiles.add(file);
        }
    }
    return inFiles;
}