扫描手机SD卡文件

SD卡：

public void initData(){
    File root = new File("/mnt/sdcard");
    if (root.exists())
    {
        currentParent = root ;
        currentFiles = root.listFiles();
        inflateListView(currentFiles);
    }
    videoListView2.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,long id)
        {
            if (currentFiles[position].isFile())
            {
                String filepath = currentFiles[position].getAbsolutePath();
                Intent intent = new Intent();
                intent.putExtra("filepath",filepath);
                intent.setClass($.getContext(), PlayActivity.class);
                startActivity(intent);
            }

            File[] tmp = currentFiles[position].listFiles();
            if (tmp == null || tmp.length == 0)
            {
                // $.toast("当前路径不可访问或该路径下没有文件",0);
            }
            else
            {
                currentParent = currentFiles[position];
                currentFiles = tmp ;
                inflateListView(currentFiles);
            }
        }
    });

    btn_parent.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            try
            {
                if (!currentParent.getCanonicalPath().equals("/mnt/sdcard/"))
                {
                    currentParent = currentParent.getParentFile();
                    currentFiles = currentParent.listFiles();
                    inflateListView(currentFiles);


                }
            } catch (IOException e)
            {
                e.printStackTrace();
            }
        }
    });

}

private void inflateListView(File[] files)
{
    List<Map<String, Object>>listItems = new ArrayList<Map<String,Object>>();
    for (int i = 0; i < files.length; i++)
    {
        Map<String, Object>listItem = new HashMap<String, Object>();
        if (files[i].isDirectory())
        {
            listItem.put("icon", R.drawable.folder);
        }
        else
        {
            listItem.put("icon", R.drawable.file);
        }
        listItem.put("fileName", files[i].getName());

        listItems.add(listItem);
    }

    SimpleAdapter adapter = new SimpleAdapter($.getContext(),listItems, R.layout.line, new String[]{"icon","fileName"}, new int[]{R.id.icon,R.id.file_name});
    videoListView2.setAdapter(adapter);

    try
    {
        tv_path2.setText("当前路径："+currentParent.getCanonicalPath());

        $.toast(tv_path2.getText().toString(),0);
        if(tv_path2.getText().toString().equals("当前路径："+"/")){
            btn_parent.setClickable(false);
            btn_parent.setText("到达最顶级");
        }else {
            btn_parent.setClickable(true);
            btn_parent.setText("返回上一级");
        }
    } catch (IOException e)
    {
        e.printStackTrace();
    }
}