为什么android在删除文件夹时会创建一个文件？

Question

我使用以下代码将图像文件保存在指定的文件夹中： -

private void captureImage(int usertype, String id) {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        mFileURI = getOutputMediaFileUri(usertype, id);

        if(mFileURI!=null)
            intent.putExtra(MediaStore.EXTRA_OUTPUT, mFileURI);
        else{
            new AlertDialog.Builder(WorkspaceActivity.this)
                .setTitle("Cannot create folder")
                .setMessage("Unable to create directory please try later.")
                .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) { 
                        // continue with delete
                    }
                 })
                .setIcon(android.R.drawable.ic_dialog_alert)
                 .show();
        }

        if(mFileURI!=null){
        // start the image capture Intent
            if (usertype == PIC_OF_TEAM) {
                startActivityForResult(intent,
                    CAMERA_CAPTURE_TEAM_IMAGE_REQUEST_CODE);
            } else if (usertype == PIC_OF_STUDENT) {
                startActivityForResult(intent,
                    CAMERA_CAPTURE_STUDENT_IMAGE_REQUEST_CODE);
            }
        }
    }

/*
 * returning image file
 */
private File getOutputMediaFile(int usertype, String id,
        String packagename) {

    String tempId               =   id;
    File mediaStorageDir        =   null;
    String userType             =   "";
    // External sdcard location
    if (usertype == PIC_OF_STUDENT) {

        String studentLocalPicUrl   =   AppConstants.STUDENT_PIC_LOCAL_URL;
        studentLocalPicUrl          =   studentLocalPicUrl.replace("/bibox/", "/bibox/"+mMentorID+"/");
        File file                   =   new File(studentLocalPicUrl);


        mediaStorageDir             =   new File(Environment.getExternalStorageDirectory(),studentLocalPicUrl);

        userType                    =   AppConstants.PIC_STUDENT;
    } else if (usertype == PIC_OF_TEAM) {

        String teamLocalPicUrl  =   AppConstants.TEAM_PIC_LOCAL_URL;
        teamLocalPicUrl         =   teamLocalPicUrl.replace("/bibox/", "/bibox/"+mMentorID+"/");
        mediaStorageDir         =   new File(
                Environment.getExternalStorageDirectory(),
                teamLocalPicUrl);
        userType    =   AppConstants.PIC_TEAM;
    }

    if (mediaStorageDir != null)
        // Create the storage directory if it does not exist
        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                Log.d("MediaHelper", "failed to create directory");
                return null;
            }
        }

    // Create a media file name
    File mediaFile      =   null;
    String imagePath    =   mediaStorageDir.getPath() + File.separator + tempId+ ".jpg";
    mediaFile           =   new File(imagePath);
    if(mediaFile.exists()){ 
        //If file already exists do this.
        do{
            imagePath           =   imagePath.replace(tempId, tempId+"_"+generateRandomNo());
            mediaFile           =   new File(imagePath);
        }while(mediaFile.exists());
    }

    //Assign the id, image path, user type
    //So that we can use it for further use in the database.
    mId         =   id;
    mMediaPath  =   imagePath;
    mUserType   =   userType;

    return mediaFile;
}


public Uri getOutputMediaFileUri(int usertype, String id) {

        File outputMediaFile    = getOutputMediaFile(usertype, id, getPackageName());

        if(outputMediaFile==null)
            return null;

        return Uri.fromFile(outputMediaFile);
    }

常量的值是： -

public static String STUDENT_PIC_LOCAL_URL = "/bibox/img/student";

问题是在拍摄图像后，如果我删除了文件夹mMentorId，那么就会创建一个0bytes的垃圾文件，该文件的屏幕截图如下所示，我试过很多关于此的搜索，但没有是富有成效的。