java - Save/Read File in android -

i want save file in android , of arraylist deleted after that.i have 2 methods write/read android file here problem want 2 methods that:

• the first method must save element of arraylist if call again not write new element in same line write in line

  • the second must read line (for example give method line , returns lines contains)

the file looks :

firstelem secondelem thridelem  anotherelem .. 

is possible in android java? ps: don't need database.

update methods :

 private void writetofile(string data) {         try {             outputstreamwriter outputstreamwriter = new outputstreamwriter(openfileoutput("config.txt", context.mode_private));             outputstreamwriter.write(data);             outputstreamwriter.close();         }         catch (ioexception e) {             log.e("exception", "file write failed: " + e.tostring());         }     }        private string readfromfile() {          string ret = "";          try {             inputstream inputstream = openfileinput("config.txt");              if ( inputstream != null ) {                 inputstreamreader inputstreamreader = new inputstreamreader(inputstream);                 bufferedreader bufferedreader = new bufferedreader(inputstreamreader);                 string receivestring = "";                 stringbuilder stringbuilder = new stringbuilder();                  while ( (receivestring = bufferedreader.readline()) != null ) {                     stringbuilder.append(receivestring);                     // stringbuilder.append("\\n");                 }                  inputstream.close();                 ret = stringbuilder.tostring();             }         }         catch (filenotfoundexception e) {             log.e("login activity", "file not found: " + e.tostring());         } catch (ioexception e) {             log.e("login activity", "can not read file: " + e.tostring());         }          return ret;     } 

using save method linked can create text save stringbuilder:

public string makearraylistflatfilestring(list<list<string>> listoflists) {     stringbuilder sb = new stringbuilder();     if (!listoflists.isempty()) {         // assumes lists same length         int listlengths = listoflists.get(0).size();         (int i=0; i<listlengths; i++)         {             (list<string> list : listoflists)             {                 sb.append(list.get(i)).append("\n");             }             sb.append("\n");  // blank line after column grouping         }     }     return sb.tostring(); } 

to parse contents same file (again assuming equal length lists , string input):

public list<list<string>> getlistoflistsfromflatfile(string data) {     // split lines     string[] lines = data.split("\\n");     // first find out how many lists we'll need     int numberoflists = 0;     (string line : lines){         if (line.trim().equals(""))         {             // blank line means new column grouping stop counting             break;         }         else         {             numberoflists++;         }     }     // make enough empty lists hold info:     list<list<string>> listoflists = new arraylist<list<string>>();     (int i=0; i<numberoflists; i++)     {         listoflists.add(new arraylist<string>());     }     // keep track of list should adding to, , populate lists     int listtracker = 0;     (string line : lines)     {         if (line.trim().equals(""))         {             // new block add next item first list again             listtracker = 0;             continue;         }         else         {             listoflists.get(listtracker).add(line);             listtracker++;         }     }     return listoflists; }