在Android中从SD卡中选择单个以及多个文件

Question

在我的应用程序中，我点击了一个按钮，打开文件选择器，选择文件后，我可以在onActivityResult（）中获取所选文件的uri。但是，我发现的问题是我总是要选择多个文件来获取uri路径。如果选择单个文件，则onActivityResult（）中不会返回任何uri数据。下面我发布我的代码。请看看。

 Uri uri = Uri.parse(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath());
            Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
            chooseFile.setDataAndType(uri, "resource/folder");
            chooseFile.putExtra(Intent.EXTRA_STREAM, uri);
            chooseFile.addCategory(Intent.CATEGORY_OPENABLE);

            //chooseFile.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);


            chooseFile.setType("*/*");
            chooseFile = Intent.createChooser(chooseFile, "Choose a file");
            startActivityForResult(chooseFile, PICKFILE_RESULT_CODE);

onActivityResult（）：

 @Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch(requestCode){
        case PICKFILE_RESULT_CODE:
            if(resultCode==RESULT_OK){

                if (data != null) {
                    ClipData clipData = data.getClipData();
                    if (clipData != null) {

                        Log.d("attachmentnumber",clipData.getItemCount()+alst_attachmentNames.size()+"");
                        if(clipData.getItemCount()>5 || (clipData.getItemCount()+alst_attachmentNames.size())>5  )
                        {
                            Toast.makeText(myContext,"attachment of 5 or less than 5 items are allowed", Toast.LENGTH_SHORT).show();
                        }
                        else
                        {
                            for (int i = 0; i < clipData.getItemCount(); i++) {
                                ClipData.Item item = clipData.getItemAt(i);
                                Uri uri = item.getUri();

                                //In case you need image's absolute path
                                try {
                                    String path= getFilePath(getActivity(), uri);
                                    alst_attachmentPaths.add(path);
                                    alst_attachmentNames.add(path.substring(path.lastIndexOf("/")+1));
                                    Log.d("pathValues", path);
                                } catch (URISyntaxException e) {
                                    e.printStackTrace();
                                }
                            }

                            LinearLayoutManager layoutManager=
                                    new LinearLayoutManager(myContext, LinearLayoutManager.HORIZONTAL, false);
                            RecyclerView.Adapter attachmentAdapter = new attachmentAdapter(myContext, alst_attachmentNames);
                            rvw_attachmentList.setLayoutManager(layoutManager);
                            rvw_attachmentList.setAdapter(attachmentAdapter);

                        Log.d("arraylistValues", Arrays.toString(alst_attachmentNames.toArray())+"/n"+
                                Arrays.toString(alst_attachmentPaths.toArray()));
                    }
                    }
                }