Hello I need fast script (in Android) which returns missing/outdated files in phone directory. This is my code, but it's pretty slow .

PHP Code:
public List<String_GetMissingFiles()
{
 
int checked_files 0;
 
 List<
String_Local_Files getLocalFiles(new File(Config._SDCARD_DIR), null);
 List<
String_FTP_Files getFTPfiles();
 List<
String_Files_Need = new ArrayList<String>();
 
 try{
     for(
int i  0< + _FTP_Files.size(); i++){
         
         
boolean found false;
         
double progress = (Double.valueOf(checked_files) / Double.valueOf(_FTP_Files.size()));
         
String[] _FTP_File_st strTok(_FTP_Files.get(i), ";");
         
String _FTP_File _FTP_File_st[0];
         
Date _FTP_File_date = new SimpleDateFormat("yyyy-MM-dd").parse(_FTP_File_st[1]);
         
         
FTP_SyncThread.doProgress("*"+_FTP_File);
         
FTP_SyncThread.doProgress("^"+(_FTP_Files.size() - checked_files));
         
FTP_SyncThread.doProgress("["+progress);
         
Log.d("FTP","checked: "+checked_files" max: "+_FTP_Files.size());
         
         for(
int x 0< + _Local_Files.size(); x++){
             
             
String[] _Local_File_st strTok(_Local_Files.get(x), ";");
             
String _Local_File _Local_File_st[0];
             
Date _Local_File_date = new SimpleDateFormat("yyyy-MM-dd").parse(_Local_File_st[1]);
             
             if(
_FTP_File.equals(_Local_File)) //Found file, now check date
             
{
                 if(
_FTP_File_date.compareTo(_Local_File_date) <= 0)
                 {
                     
//DATE OK
                     
found true;
                     
//Log.i("FTP","[OK]: File Found: "+_FTP_File);
                     
break;
                 }
             } 
         }
         
         
checked_files += 1;
         
         if(!
found)
         {
             
//Log.w("FTP","[ERR]: File Not Found or outdated: "+_FTP_File);
             
_Files_Need.add(_FTP_File);
         }
     }
 }
 catch (
ParseException e) {
        
Log.e("FTP","Catch error: "+e.getMessage());
    }

 return 
_Files_Need;

It's like loop in loop, that's why it's slow . Any better ideas?