Android implements folder sorting based on name, time and size

/**
  * Sort by file name
  * @param filePath
  */
 public static ArrayList<String> orderByName(String filePath) {
 ArrayList<String> FileNameList = new ArrayList<String>();
 File file = new File(filePath);
 File[] files = ();
 List fileList = (files);
 (fileList, new Comparator<File>() {
  @Override
  public int compare(File o1, File o2) {
  if (() && ())
   return -1;
  if (() && ())
   return 1;
  return ().compareTo(());
  }
 });
 for (File file1 : files) {
  if (()) {
  (());
  }
 }
 return FileNameList;
 }

/**
  * Sort by file modification time
  * @param filePath
  */
 public static ArrayList<String> orderByDate(String filePath) {
 ArrayList<String> FileNameList = new ArrayList<String>();
 File file = new File(filePath);
 File[] files = ();
 (files, new Comparator<File>() {
  public int compare(File f1, File f2) {
  long diff = () - ();
  if (diff > 0)
   return 1;
  else if (diff == 0)
   return 0;
  else
   return -1;// If the if is modified to return -1 and the order will be decremented  }
 
  public boolean equals(Object obj) {
  return true;
  }
 
 });
 
 for (File file1 : files) {
  if (()) {
  (());
  }
 }
 return FileNameList;
 }

/**
  * Sort by file size
  * @param filePath
  */
 public static ArrayList<String> orderBySize(String filePath) {
 ArrayList<String> FileNameList = new ArrayList<String>();
 File file = new File(filePath);
 File[] files = ();
 List<File> fileList = (files);
 (fileList, new Comparator<File>() {
  public int compare(File f1, File f2) {
  long s1 = getFolderSize(f1);
  long s2 = getFolderSize(f2);
 
  long diff = s1 - s2;
  if (diff > 0)
   return 1;
  else if (diff == 0)
   return 0;
  else
   return -1;// If the if is modified to return -1 and the order will be decremented  }
 
  public boolean equals(Object obj) {
  return true;
  }
 });
 
 for (File file1 : files) {
  if (()) {
  (());
  }
 }
 return FileNameList;
 }
 
 /**
  * Get folder size
  * @param file File instance
  * @return long
  */
 public static long getFolderSize(File file) {
 
 long size = 0;
 try {
  [] fileList = ();
  for (int i = 0; i < ; i++) {
  if (fileList[i].isDirectory()) {
   size = size + getFolderSize(fileList[i]);
  } else {
   size = size + fileList[i].length();
  }
  }
 } catch (Exception e) {
  ();
 }
 return size;
}