java - save string list to a file since you compare it -

i saving file double list (mydata) data user enters , string list (dates_strings) current date.

the user enters data , pressing 'save' button , save data , currents date.

so , user may enter "1" , press save (1, 08/05/13)

enter "2" , press save (2, 08/05/13).

because user may enter data during day (same date) don't want save many instances of date.i want save user data in date.

i tried sth like:

 (int i=1;i<mydata.size();i++){                    bw.write(mydata.get(i)+",");             while (!(dates_strings.get(i).equals(dates_strings.get(i-1))))                                    bw.write(dates_strings.get(i)+"\n");               } 

but saves last entered data.

i saving as:

file sdcard = environment.getexternalstoragedirectory();         file directory = new file (sdcard, "myfiles");         directory.mkdirs();                     file file = new file(directory, filename);          fileoutputstream fos;          //saving them         try {            fos = new fileoutputstream(file,true); //true in order append                bufferedwriter bw = new bufferedwriter(new outputstreamwriter(fos));                (int i=1;i<mydata.size();i++){                      //if (!(dates_strings.get(i).equals(dates_strings.get(i-1))))                                       bw.write(mydata.get(i)+","+dates_strings.get(i)+"\n");               }               value.settext("");               bw.flush();               bw.close();              } catch (ioexception e2) {                e2.printstacktrace();                 }//catch     } 

i loading as:

 file sdcard = environment.getexternalstoragedirectory();     file directory = new file (sdcard, "myfiles");     file file = new file(directory, filename);      string s;      fileinputstream fis;     try {       fis = new fileinputstream(file);           bufferedreader br = new bufferedreader(new inputstreamreader(fis));           {              s = br.readline();                   if (s != null ){                  string[] splitline = s.split(",");                  mydata.add(double.parsedouble(splitline[0]));                  //dates_strings.add(thedate.parse(splitline[1]));                  dates_strings.add(splitline[1]);        }                                      } while (s != null );           br.close();                              } catch (ioexception e) {           e.printstacktrace();            } } 

mmmm... maybe can you, basic idea mentioned our colleagues: receive input, save in file, receive new input, read existing file before, add new content old content , save updated content of file.

//asumming values these:         list<string> dateslist = new arraylist<string>();         list<double> datalist = new arraylist<double>();         //you must fill data of course...         //i use buffer put in order data          stringbuffer stringappender = new stringbuffer();                (int = 0; < datalist.size(); i++) {             stringappender.append(datalist.get(i));             stringappender.append(",");             stringappender.append(dateslist.get(i));             if (i != datalist.size()-1) {                 stringappender.append("\n");             }         }         //i use buffered writer , save data ordered in 1 single string.         bufferedwriter bw = new bufferedwriter(new filewriter(new file("/home/mtataje/saved.txt")));                 bw.write(stringappender.tostring());         bw.close(); 

then... have new inputs right?

        //i read file first     bufferedreader br = new bufferedreader(new filereader(new file("/home/mtataje/saved.txt")));     string line;      stringbuffer auxbuffer = new stringbuffer();      while ((line = br.readline()) != null) {         auxbuffer.append(line);         auxbuffer.append("\n");     }      //then append stringbuffer again, stringbuffer has data saved inside :)     (int = 0; < newdatalistincoming.size(); i++) {         auxbuffer.append(newdatalistincoming.get(i));         auxbuffer.append(",");         auxbuffer.append(newdatesincoming.get(i));         if (i != newdatalistincoming.size()-1) {             auxbuffer.append("\n");         }     }     //and write file     bufferedwriter bw2 = new bufferedwriter(new filewriter(new file("/home/mtataje/saved.txt")));            bw2.write(auxbuffer.tostring());     bw2.close(); 

of course, use methods , not use redundancy in code me, hope gave hand this. best regards.