How could I get a valid LookupElement set for the path auto completion?

Hi, 

I'm developing a plugin for the NEJ, which is a JavaScript framework. It's package resolve is similar to the define.js. The grammar shows below.

NEJ.define([
    'base/element',
    'pro/extend/util',
    '/path/to/file.js',
    '{platform}patch.js',
    'text!/path/to/file.css',
    'text!/path/to/file.html'
],function(e,u,t,h,css,html,p,o,f,r){

    // TODO something

    // 返回结果可注入给其他文件
    return p;
});

I have implement a class extending PsiReferenceBase<PsiElement>, and make the method resolve work well.
Now I wanna to implement getVariants which offering us a auto-completion. But I have encountered some problem. For example, when I type "./", and trigger basic-completion, I resolve the path "./", and get all children of the directory. And then, use the code:

final VirtualFile fileByPath = LocalFileSystem.getInstance().findFileByPath(String.valueOf(path.normalize()));

        final PsiManager instance = PsiManager.getInstance(myElement.getProject());

        for (VirtualFile file : fileByPath.getChildren()) {
//                            .withTypeText(file.getName())

            if (file.isDirectory()) {
                final PsiDirectory file1 = instance.findDirectory(file);
                completionResultSet.add(
                        LookupElementBuilder
                                .create(file1).withTypeText(file1.getName())

                );
            }else{
                final PsiFile file1 = instance.findFile(file);
                completionResultSet.add(
                        LookupElementBuilder
                                .create(file1).withTypeText(file1.getName())

                );
            }
        }

to return a completionResultSet. And this is my debug result:

You can see, it do have correct completion suggestions, but the IDE says there is no suggestions. I have found that, someone said getVariants should give all those resolvable but not matching all string. I can't understand it. Could someone tell me how to fixed it?