Question

Using J2ME, netbeans 7.2, Developing a mobile app..

I have converted the Datefield value to a String and Now want to put it back to a Datefield. To do this I need to convert the String back to Datefield, I am using the following code but its not happening.

long myFileTime = dateField.getDate().getTime(); // getting current/set date from the datefield into long
         String date = String.valueOf(myFileTime); // converting it to a String to put it back into a different datefield

         Date updatedate= stringToDate(date); // passing the string 'date' to the Method stringToDate() to convert it back to date.
                 dateField1.setDate(updatedate); // updating the date into the new datefield1

public Date stringToDate(String s) 
{
    Calendar c = Calendar.getInstance();

    c.set(Calendar.DAY_OF_MONTH, Integer.parseInt(s.substring(0, 2)));
    c.set(Calendar.MONTH, Integer.parseInt(s.substring(3, 5)) - 1);
    c.set(Calendar.YEAR, Integer.parseInt(s.substring(6, 10)));

    return c.getTime();
}

Answer 1

Since you have mentioned that you have the long myFileTime around, you should be able to use:

Date updatedate=new Date(myFileTime);

To convert back to your date. If only your String is available, you should modify your function to this:

public Date stringToDate(String s){
  Calendar c = Calendar.getInstance();

  c.set(Calendar.DAY_OF_MONTH, Integer.parseInt(s.substring(0, 2)));
  c.set(Calendar.MONTH, Integer.parseInt(s.substring(2, 4))-1 );
  c.set(Calendar.YEAR, Integer.parseInt(s.substring(4, 8)));

  return c.getTime();
}

Note the changed indexes.

In Java SE, you should be able to use the following line, instead of setting each fields separately:

c.setTimeInMillis(Long.parseLong(s));

Since in s you have the dateField.getDate().getTime() that is equal to myFileTime, the number of seconds starting with January 1, 1970, based on your provided code.

Your stringToDate should work only if your string will have the following format: ddMMyyyy. Also note that in this case you should use a SimpleDateFormat to parse, something like:

Date updatedate = new java.text.SimpleDateFormat("ddMMyyyy HH:mm:ss").parse(date);