Question

在我的文件浏览器应用程序中，我试图在任何文件夹中只显示xml文件。所以每次打开文件夹时，我只想显示xml文件。我查看了这个网站和互联网上有大量的例子，但是在C＃中找不到一个例子。我也尝试根据我的需要修改其他例子，但是我实施了IFileNameFilter类。有人知道吗怎么做？我试图实现它，但不断出现构建错误。

在下面的代码中，我有一个显示文件的ListFragment类：

public override void OnListItemClick(ListView l, View v, int position, long id)
    {

        try{

        var fileSystemInfo = _adapter.GetItem(position);


        if (fileSystemInfo.IsFile())
        {
            // Do something with the file.  In this case we just pop some toast.
            Log.Verbose("FileListFragment", "The file {0} was clicked.", fileSystemInfo.FullName);
            Toast.MakeText(Activity, "You selected file " + fileSystemInfo.FullName, ToastLength.Short).Show();

            OnFileClick (fileSystemInfo);
        }
        else
        {
            // Dig into this directory, and display it's contents

                RefreshFilesList(fileSystemInfo.FullName);
        }

        }catch(Exception e){

            Log.Error (TAG,e.ToString());

        }

        base.OnListItemClick(l, v, position, id);


    }

public void RefreshFilesList(string directory)
    {

        //GenericExtFilter filter = new GenericExtFilter(extension);

        IList<FileSystemInfo> visibleThings = new List<FileSystemInfo>();

        var dir = new DirectoryInfo(directory);

        try
        {
            foreach (var item in dir.GetFileSystemInfos().Where(item => item.IsVisible()))
            {

                visibleThings.Add(item);

            }
        }
        catch (Exception ex)
        {
            Log.Error("FileListFragment", "Couldn't access the directory " + _directory.FullName + "; " + ex);
            Toast.MakeText(Activity, "Problem retrieving contents of " + directory, ToastLength.Long).Show();
            return;
        }

        _directory = dir;

        _adapter.AddDirectoryContents(visibleThings);

        // If we don't do this, then the ListView will not update itself when the data set 
        // in the adapter changes. It will appear to the user that nothing has happened.
        ListView.RefreshDrawableState();

        Log.Verbose("FileListFragment", "Displaying the contents of directory {0}.", directory);
    }

Answer 1

如果我理解正确，你想创建将过滤XML文件的IFilenameFilter。

public class XmlFileFilter : Java.Lang.Object, IFilenameFilter
{
    public bool Accept(File dir, string filename)
    {
        return filename.ToLower().EndsWith(".xml");
    }
}

Answer 2

我用一个简化的解决方案解决了这个问题。毕竟我没有使用IFileNameFilter。在上面的RefreshFilesList方法中，我进行了以下更改：

foreach (var item in dir.GetFileSystemInfos().Where(item => item.IsVisible()))
            {
                if(item.IsDirectory())
                {

                    visibleThings.Add(item);

                }else if(item.IsFile())
                {

                    bool isXmlFile = item.Extension.ToLower().EndsWith("xml");
                    if(isXmlFile)
                    {
                    visibleThings.Add(item);
                    }

                }
            }

现在显示所有文件夹和任何xml文件。

xamarin.Android C＃ - IFileNameFilter类的实现问题

2 个答案: