Android: How to open a specific folder via Intent and show its content in a file browser?

I thought this would be easy but as it turns out unfortunately it's not.

What I have:

I have a folder called "myFolder" on my external storage (not sd card because it's a Nexus 4, but that should not be the problem). The folder contains some *.csv files.

What I want:

I want to write a method which does the following: Show a variety of apps (file browsers) from which I can pick one (see picture). After I click on it, the selected file browser should start and show me the content of "myFolder". No more no less.

My question:

How exactly do I do that? I think I came quite close with the following code, but no matter what I do - and I'm certain that there must be something I didn't get right yet - it always opens only the main folder from the external storage.

public void openFolder()
{
File file = new File(Environment.getExternalStorageDirectory(),
    "myFolder");

Log.d("path", file.toString());

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setDataAndType(Uri.fromFile(file), "*/*");
startActivity(intent);
}

I finally got it working. This way only a few apps are shown by the chooser (Google Drive, Dropbox, Root Explorer, and Solid Explorer). It's working fine with the two explorers but not with Google Drive and Dropbox (I guess because they cannot access the external storage). The other MIME type like "*/*" is also possible.

public void openFolder(){
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    Uri uri = Uri.parse(Environment.getExternalStorageDirectory().getPath()
         +  File.separator + "myFolder" + File.separator);
    intent.setDataAndType(uri, "text/csv");
    startActivity(Intent.createChooser(intent, "Open folder"));
}