重复条件分割的文本区域

Question

I have a text area wherein i have limited the user from entering more that 15 characters in one line as I want to get the free flow text separated into substrings of max limit 15 characters and assign each line an order number. This is what I was doing in my java class:

int interval = 15;                
items = new ArrayList();
 TextItem item = null;
 for (int i = 0; i < text.length(); i = i + interval) {
  item = new TextItem ();
  item.setOrder(i);

  if (i + interval < text.length()) {
    item.setSubText(text.substring(i, i + interval));
    items.add(item);
  } 
  else {
    item.setSubText(text.substring(i));
    items.add(item);
  }
}

Now it works properly unless the user presses the enter key. Whenever the user presses the enter key I want to make that line as a new item having only that part as the subText.

I can check whether my text.substring(i, i + interval ) contains any "\\n" and split till there but the problem is to get the remaining characters after "\\n" till next 15 or till next "\\n" and set proper order and subText.

Answer 1

You could reverse the order of doing things: First, split the content of your text area at occurences of '\\n'. Then take each of the resulting strings and split them into parts of maximum length 15.

Edit: I'm not totally sure about what you want to do, but here's what I would do. Note that I'm not a Java programmer, so I might be making false assumptions, and the following is untested.

int interval = 15;                
items = new ArrayList();
lines = text.split("\n");
for (int i = 0; i < lines.length(); i++)
{
  str = lines[i];
  while (str.length() > interval)
  {
    items.add(str.substring(0,interval)); // add the first 15 characters of str to the list
    str = str.substring(interval); // ... and remove them from str
  }
  items.add(str); // add the rest
}

After that, items is an ArrayList of strings that are in the correct order. It should be possible to extend this code to whatever additional information you need to store with the actual strings.

Answer 2

Is this what you're trying to do?

public static void main(String[] args)
{
  String str =
  "\n\n123456789ABCDEF123456\n123456789AB\n\n123" +
  "456789ABCDEF123456789AB\n123456789ABCDEF\n";

  List<String> parts = new ArrayList<String>();

  // remove leading line separators
  str = str.replaceFirst("\\A[\r\n]+", "");

  // match up to 15 non-newline characters, but don't
  // match a zero-length string at the end
  Matcher m = Pattern.compile("(?!\\z).{0,15}").matcher(str);
  while (m.find())
  {
    parts.add(m.group());
  }

  for (String s : parts)
  {
    System.out.println(s);
  }
}

result:

123456789ABCDEF
123456

123456789AB


123456789ABCDEF
123456789AB

123456789ABCDEF