在调用onActivityResult（）之前限制附件数量

Question

我的应用程序中有一个文件上传模块，点击按钮，选择并上传外部存储目录（Google Drive）中的文件。根据要求，我可以选择最多5个文件，这可以通过一次选择5个文件或分割为2个文件然后再选择3个文件来完成。我只想在选择了5个以上的文件后通知用户。目前，我可以在调用onActivityResult（）后通知用户。有什么办法可以将选择限制在5个文件中并通过Google云端硬盘自行通知用户吗？

请在下面找到我目前正在运行的代码：

   txtv_attach.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v)
        {
            int_permission_type = 1;
            if(Build.VERSION.SDK_INT >= 23) {
                if (CheckingPermissionIsEnabledOrNot()) {

                    Toast.makeText(myContext, "All Permissions Granted Successfully", Toast.LENGTH_LONG).show();
                    start_attachment_activity();
                }

                // If, If permission is not enabled then else condition will execute.
                else {

                    //Calling method to enable permission.
                    RequestMultiplePermission();

                }
            }

            else
            {
                start_attachment_activity();
            }
        }
    });

现在是start_attachment_activity（）：

  public void  start_attachment_activity()
{
    String[] mimeTypes =
            {"image/*","application/pdf","application/msword","application/vnd.ms-powerpoint","application/vnd.ms-excel","text/plain","audio/", "video/"};

    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.putExtra(Intent.EXTRA_MIME_TYPES, mimeTypes);
    chooseFile = Intent.createChooser(chooseFile, "Choose a file");
    startActivityForResult(chooseFile, PICKFILE_RESULT_CODE);
}

现在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.getData() != null) {
                    if((alst_attachmentNames.size()+1)>5)
                    {
                        Toast.makeText(myContext,"attachment of 5 or less than 5 items are allowed", Toast.LENGTH_SHORT).show();
                    }
                    else
                    {
                        Uri dataURI = data.getData();
                        try {
                            String path= getFilePath(getActivity(), dataURI);
                            if(path!=null)
                            {
                                alst_attachmentPaths.add(path);
                                alst_attachmentNames.add(path.substring(path.lastIndexOf("/")+1));
                                LinearLayoutManager layoutManager=
                                        new LinearLayoutManager(myContext, LinearLayoutManager.HORIZONTAL, false);
                                RecyclerView.Adapter attachmentAdapter = new attachmentAdapter(myContext, alst_attachmentNames);
                                rvw_attachmentList.setLayoutManager(layoutManager);
                                rvw_attachmentList.setAdapter(attachmentAdapter);
                            }


                        } catch (URISyntaxException e) {
                            String err = (e.getMessage()==null)?"SD Card failed":e.getMessage();
                            Log.e("sdcard-err2:",err);
                        }

                    }


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

                        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));
                                } 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);

                    }
                    }
                }

            }
            break;

    }
}

如果我遗失了什么，请告诉我。我想控制驱动器本身的文件选择数量。需要你的帮助。提前谢谢。