Android：列表中的特定文件

Question

我想在我的Android应用中阅读文件。在我的活动中，我将文件加载到列表中，然后显示所选文件的路径。但是，我需要File对象进行下一步，这是我的代码：

public class MainActivity extends ActionBarActivity{

    final StringBuffer sb = new StringBuffer();

    private ListView mainListView;  
    private ArrayAdapter<String> listAdapter;  

    String filepath;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mainListView = (ListView) findViewById(R.id.mainListView);  
        final ArrayList<String> List = new ArrayList<String>();  

        final File storage = Environment.getExternalStorageDirectory();
        final File file = new File(storage, "/Folder/");

        if(file.exists() && file.isDirectory()){
            for (String s : file.list()){
                sb.append(s + " ");

                List.addAll(Arrays.asList(s));
            }
        }

        listAdapter = new ArrayAdapter<String>(this, R.layout.simplerow, R.id.rowTextView,List); 
        mainListView.setAdapter(listAdapter);  

        mainListView.setOnItemClickListener(new OnItemClickListener(){
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3){
                String filepath = new File("/Folder/"+ List.get(arg2)).getAbsolutePath();
            }
        });
    }

我该如何解决这个问题？下一个方法有输入（文件文件）