如何限制文本框的长度？

Question

我正在使用swt jface与rcp一起研究eclipse java。 如何限制文本框中的字符。就像我的文本框中只需要4个字符一样，那我该怎么办？如果我想要字母数字组合怎么办？再次在一定限度内？

Answer 1

请查看此功能示例以限制字符

function check_length_year(my_form) {
  maxLen = 4; // max number of characters allowed
  if (my_form.retire_year.value.length > maxLen) {
  // Alert message if maximum limit is reached.
  // If required Alert can be removed.
  // var msg = "You have reached your maximum limit of characters allowed";
  // alert(msg);
  // Reached the Maximum length so trim the textarea
     my_form.retire_year.value = my_form.retire_year.value.substring(0, maxLen);
     return false;
  } else { // Maximum length not reached so update the value of my_text counter
     my_form.year_num.value = maxLen - my_form.retire_year.value.length;}
  } 

Answer 2

这对你有用吗？

SWT / LimitthenumberofcharactersthattheStyledTextaccepts.htm“＆GT; HTTP：//www.java2s.com/Tutorial/Java/0280_SWT/LimitthenumberofcharactersthattheStyledTextaccepts.htm

Answer 3

答案的一半：

text.setTextLimit(4);