A simple Storage manager demo listing the files within the Codename One storage and allowing us to add/view/remove them.

StorageManagerSample.java

public void showForm() {
    Toolbar.setGlobalToolbar(true);
    Form hi = new Form("Storage", new BoxLayout(BoxLayout.Y_AXIS));
    hi.getToolbar().addCommandToRightBar("+", null, (e) -> {
        TextField tf = new TextField("", "File Name", 20, TextField.ANY);
        TextArea body = new TextArea(5, 20);
        body.setHint("File Body");
        Command ok = new Command("OK");
        Command cancel = new Command("Cancel");
        Command result = Dialog.show("File Name", BorderLayout.north(tf).add(BorderLayout.CENTER, body), ok, cancel);
        if(ok == result) {
            try(OutputStream os = Storage.getInstance().createOutputStream(tf.getText())) {
                os.write(body.getText().getBytes("UTF-8"));
                createFileEntry(hi, tf.getText());
                hi.getContentPane().animateLayout(250);
            } catch(IOException err) {
                Log.e(err);
            }
        }
    });
    
    for(String file : Storage.getInstance().listEntries()) {
        createFileEntry(hi, file);
    }
    hi.show();
}

private void createFileEntry(Form hi, String file) {
   Label fileField = new Label(file);
   Button delete = new Button();
   Button view = new Button();
   FontImage.setMaterialIcon(delete, FontImage.MATERIAL_DELETE);
   FontImage.setMaterialIcon(view, FontImage.MATERIAL_OPEN_IN_NEW);
   Container content = BorderLayout.center(fileField);
   int size = Storage.getInstance().entrySize(file);
   content.add(BorderLayout.EAST, BoxLayout.encloseX(new Label(size + "bytes"), delete, view));            
   delete.addActionListener((e) -> {
       Storage.getInstance().deleteStorageFile(file);
       content.setY(hi.getWidth());
       hi.getContentPane().animateUnlayoutAndWait(150, 255);
       hi.removeComponent(content);
       hi.getContentPane().animateLayout(150);
   });         
   view.addActionListener((e) -> {
       try(InputStream is = Storage.getInstance().createInputStream(file)) {
           String s = Util.readToString(is, "UTF-8");
           Dialog.show(file, s, "OK", null);
       } catch(IOException err) {
           Log.e(err);
       }
   });
   hi.add(content);
} 

Sample usage of the Storage class.

From the Codename One project