I need a function to return true or false, depending on the amount of letters

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boolean b = mascara.matches("\\D{0,4}");

I need a mask (like for example "GHO-1A23") is verified to contain only 4 letters.

If you have 4 type only number and if you have less than 4 let type one more letter.

But this way above, it returns false when the user will type a next letter already with the mask being "GHO-1".

java android regex

  • Thank you! I wasn’t getting to put as code

  • To help center has several tips for formatting the code. And \\D{0,4} checks if the string contains between zero and 4 characters that are not digits. That is, if it has 1 letter, it works. If it has none, it also works. But if it has a digit, it doesn’t work. It doesn’t check if it has exactly 4 letters. Another detail is that matches checks if the whole string matches the expression. If the mask is GHO-1, it has a digit and so does not correspond to \\D{0,4} (between zero and 4 characters that are not digits) - so returns false

  • 1

    According to a question performed by you yesterday. Vc wanted to validate boards. But the code you were creating was to insert a plate mask. You need to be a little more objective in the question, because the answer you get might not meet. Just to try to help you a little, in the real world, when you have Mediterranean plates, you will still have old model plates LLL-NNNN (L - letter and N - number). How your code will meet the 2 possibilities?

  • I solved the problem. The complete class solves the two possibilities.

  • 1

    Then create an answer by placing the code. It can help future users who have the same question as yours.

1 answer

2

So I changed the regex expression:

mascara.matches("\\D{0,4}|\\D{0,4}\\d{0,2}|\\D{0,4}\\d{0,3}");

My test has handled all the cases, including the old plates, but if anyone finds any disagreement, I’ll be happy to let you know.

import android.text.Editable;
import android.text.InputFilter;
import android.text.InputType;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.Toast;



public class PlacaUtils {

    HomeActivity context;

    public static String unmask(String s) {
        return s.replaceAll("[.]", "").replaceAll("[-]", "")
                .replaceAll("[/]", "").replaceAll("[(]", "")
                .replaceAll("[)]", "");
    }

    public static TextWatcher insert(final EditText ediTxt) {
        return new TextWatcher() {
            String mask = "UUU-####";
            boolean isUpdating;
            String old = "";


            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {
                ediTxt.setFilters(new InputFilter[]{new InputFilter.AllCaps()});
                String str = PlacaUtils.unmask(s.toString());
                String mascara = "";
                if (isUpdating) {
                    old = str;
                    isUpdating = false;
                    return;
                }
                int i = 0;
                for (char m : mask.toCharArray()) {
                    if ((m != '#' && m != 'U') && str.length() > old.length()) {
                        mascara += m;
                        continue;
                    }
                    try {
                        Character c = str.charAt(i);
                        if (mascara.length() < 3) {
                            if (Character.isLetter(c)) {
                                mascara += str.charAt(i);
                            }
                        } else if (mascara.length() >= 3) {
                            if (Character.isDigit(c)) {
                                mascara += str.charAt(i);
                            } else if (Character.isLetter(c)) {
                                boolean b = mascara.matches("\\D{0,4}|\\D{0,4}\\d{0,2}|\\D{0,4}\\d{0,3}");
                                if (b) {
                                    mascara += str.charAt(i);
                                }

                            }
                        }
                    } catch (Exception e) {
                        break;
                    }
                    i++;
                }
                isUpdating = true;
                if (str.length() < 3) {
                    ediTxt.setInputType(InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS);
                } else if (str.length() >= 3) {
                    ediTxt.setInputType((InputType.TYPE_CLASS_TEXT));
                }

                ediTxt.setText(mascara);
                ediTxt.setSelection(mascara.length());


            }

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
            }

            public void afterTextChanged(Editable s) {
            }
        };
    }

    public static boolean isValid(final String placa) {
        if (StringUtils.isEmpty(placa)) {
            return false;
        }

        if (placa.matches("[A-Z]{3}[0-9][A-Z][0-9]{2}")) {
            return true;
        } else {
            return false;
        }
    }

    public static String masked(String placa) {

        placa = unmask(placa);
        placa = placa.substring(0, 3) + "-" + placa.substring(3, 7);

        return placa;
    }
}
  • 1

    If decided, remember to check how accepted later to close the post

  • 1

    Take advantage and remove your old question, which was similar to this, then the site gets more organized and you recover your points.

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