How to recursively scan directories in Android

How can I recursively scan directories in Android and display file name(s)? I’m trying to scan, but it’s slow (force close or wait). I’m using the FileWalker class given in a separate answer to this question.

Answer

You should almost always access the file system only from a non-UI thread. Otherwise you risk blocking the UI thread for long periods and getting an ANR. Run the FileWalker in an AsyncTask‘s doInBackground().

This is a slightly optimized version of FileWalker:

public class Filewalker {

    public void walk(File root) {

        File[] list = root.listFiles();

        for (File f : list) {
            if (f.isDirectory()) {
                Log.d("", "Dir: " + f.getAbsoluteFile());
                walk(f);
            }
            else {
                Log.d("", "File: " + f.getAbsoluteFile());
            }
        }
    }
}

You can invoke it from a background thread like this:

Filewalker fw = new Filewalker();
fw.walk(context.getFilesDir());