Androidアプリでのファイル選択(パスの取得)

はじめまして、Androidアプリ開発を始めたばかりのものです。
現在はオーディオプレイヤーアプリを試しに作るため http://qiita.com/matyapiro31/items/abd852362bca856d3446 さんを参考にファイル選択機能を実装しようとしています。
恥ずかしながらプログラムをほとんど読み解けていないこともあり、new TranslateなどTranslate変数全てでエラーが発生しています。
もし宜しければ、Translate変数についての解説をお願い致します。

OpenFileDialog.java
package com.example.www;

import android.content.DialogInterface;

public class OpenFileDialog {
    public OpenFileDialog() {
        try {
            this.init("/");
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
        path = "/";
        MenuWords = new Translate(new String[] {"Open", "Open ...", "Move", "Cancel"},
                new String[] {"open", "open_title", "move", "cancel"});
    }
    public OpenFileDialog(String openDir) {
        try {
            this.init(openDir);
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
        if (openDir.startsWith("//")) {
            path = openDir.substring(1);
        } else {
            path = openDir;
        }
        MenuWords = new Translate(new String[] {"Open", "Open ...", "Move", "Cancel"},
                new String[] {"open", "open_title", "move", "cancel"});
    }
    public void init(String dirname) throws java.io.IOException{
        java.io.File file= new java.io.File(dirname);
        int counter = 0;

        if (!file.getCanonicalPath().equals("/")) {
            int size = file.list()!=null ? file.list().length:0;
            items = new String[size + 1];
            items[0] = "../";
            if (file.list()!=null) {
                java.lang.System.arraycopy(file.list(),0,items,1,size);
                counter = 1;
            }
        } else {
            items = file.list()!=null?file.list():new String[] {""};
            counter = 0;
        }
        for (;counter<items.length;counter++) {
            java.io.File iItem = new java.io.File(dirname + "/" + items[counter]);
            if (iItem.isDirectory()) {
                items[counter] += "/";
            }
        }
        if (items[0].equals("..//")) {
            items[0] = "../";
        }
    }

    public int move(android.content.Context context,OpenMode mode, String path) {
        OpenFileDialog childopenfiledialog = new OpenFileDialog(path);
        childopenfiledialog.openFileAction = openFileAction;
        childopenfiledialog.MenuWords = MenuWords;
        try {
            childopenfiledialog.createOpenFileDialog(context, mode).show();
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
        return 0;
    }

    public interface OpenFileAction {
        java.io.File write(java.io.File file);
        java.io.File append(java.io.File file);
        void read(java.io.File file);
        String toString();
    }

    public enum OpenMode {
        Write,Append,Read
    }
    public OpenFileAction openFileAction;
    private String path;
    public String[] items;
    public Translate MenuWords;

    public android.app.AlertDialog.Builder createOpenFileDialog(final android.content.Context context,final OpenFileDialog.OpenMode mode)
            throws java.io.IOException {
        final java.util.ArrayList<Integer> checkedItems = new java.util.ArrayList<>();
        final android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder(context);
        builder.setTitle(MenuWords.translation.get("open_title"))
                .setMultiChoiceItems(items, null, new android.content.DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(android.content.DialogInterface dialog, int which, boolean isChecked) {
                        if (isChecked) checkedItems.add(which);
                        else checkedItems.remove((Integer) which);
                    }
                })
                .setPositiveButton(MenuWords.translation.get("open"), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(android.content.DialogInterface dialog, int which) {

                        for (Integer i : checkedItems) {
                            // item_i checked
                            // note: i is undefined when not checked. use switch to do work.

                            // insert / as double / is allowed and no / is error.
                            java.io.File file = new java.io.File(path + "/" + items[i]);
                            switch (mode) {
                                case Write:
                                    openFileAction.write(file);
                                    break;
                                case Append:
                                    openFileAction.append(file);
                                    break;
                                case Read:
                                    openFileAction.read(file);
                                    break;
                                default:
                                    android.util.Log.d("FileState", openFileAction.toString());
                            }
                        }
                    }
                })
                .setNegativeButton(MenuWords.translation.get("cancel"), null)
                .setNeutralButton(MenuWords.translation.get("move"), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(android.content.DialogInterface dialog, int which) {
                        if (checkedItems.size()==1) {
                            for (Integer i: checkedItems
                                 ) {
                                if (items[i].endsWith("../")) {
                                    String nextPath = "/";
                                    char[] pArray = path.toCharArray();
                                    int slash = 0;
                                    for (int j=0;j<pArray.length-1;j++) {
                                        if (pArray[pArray.length-1-j] == '/') {
                                            slash++;
                                        }
                                        if (slash==3) {
                                            nextPath = path.substring(0,pArray.length-j);
                                            break;
                                        }
                                    }
                                    move(context, mode, nextPath);
                                } else {
                                    if (items[i].endsWith("/")) {
                                        if (path.endsWith("/")) {
                                            move(context, mode, path + items[i]);
                                        } else {
                                            move(context, mode, path + "/" +items[i]);
                                        }
                                    }
                                }
                            }
                        }
                    }

        });
        return builder;
    }
}

Android Studioを使って開発しています。