Automatically add dash in phone number in Android

Question

Instead of 5118710, it should be 511-8710. I\'d like to add a dash after the user the user inputted 3 digits already in the EditText. The maximum length of

Answer 1

import android.text.Editable;
import android.text.Selection;
import android.text.TextWatcher;
import android.util.Log;
import android.widget.EditText;

/**
 * Auto-formats a number using -.
 * Ex. 303-333-3333
 * Ex. 1-303-333-3333
 * Doesn't allow deletion of just -
 */
public class PhoneNumberFormattingTextWatcher implements TextWatcher {
    private static final String TAG = "PhoneNumberTextWatcher";

    private final EditText editText;
    private String previousNumber;

    /**
     * Indicates the change was caused by ourselves.
     */
    private boolean mSelfChange = false;

    public PhoneNumberFormattingTextWatcher(EditText editText) {
        this.editText = editText;
    }

    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void afterTextChanged(Editable editable) {
        // if the previous editable ends with a dash and new is shorter than previous
        // additionally remove preceding character
        Log.i(TAG, "Previous String: " + previousNumber);

        //if self change ignore
        if (mSelfChange) {
            Log.i(TAG, "Ignoring self change");
            mSelfChange = false;
            return;
        }

        String phoneNumber = removeNonnumeric(editable.toString());
        int stringLength = phoneNumber.length();

        //empty case
        if(stringLength == 0) {
            mSelfChange = true;
            editText.setText("");
            return;
        }

        boolean startsWithOne = phoneNumber.charAt(0) == '1';
        int maxLength = 10 + (startsWithOne ? 1 : 0);

        //too large
        if(stringLength > maxLength) {
            Log.i(TAG, "String length is greater than max allowed, using previous string: " + previousNumber);
            mSelfChange = true;
            editText.setText(previousNumber);
            Editable etext = editText.getText();
            Selection.setSelection(etext, previousNumber.length());
            return;
        }

        phoneNumber = formatPhoneNumber(phoneNumber);

        if(previousNumber != null && phoneNumber.length() == previousNumber.length()) {
            //user deleting last character, and it is a -
            if(phoneNumber.endsWith("-")) {
                phoneNumber = phoneNumber.substring(0, phoneNumber.length()-2);
            }
        }

        mSelfChange = true;
        previousNumber = phoneNumber;
        editText.setText(phoneNumber);
        Editable etext = editText.getText();
        Selection.setSelection(etext, phoneNumber.length());
    }

    private String formatPhoneNumber(String phoneNumber) {
        int stringLength = phoneNumber.length();
        //check if starts with 1, if it does, dash index is increased by 1
        boolean startsWithOne = phoneNumber.charAt(0) == '1';

        //if the length of the string is 6, add another dash
        int lastHyphenIndex = 6 + (startsWithOne ? 1 : 0);
        if (stringLength >= lastHyphenIndex) {
            phoneNumber = phoneNumber.substring(0, lastHyphenIndex) + "-" + phoneNumber.substring(lastHyphenIndex, phoneNumber.length());
        }
        //if the length of the string is 3, add a dash
        int secondToLastHyphenIndex = 3 + (startsWithOne ? 1 : 0);
        if (stringLength >= secondToLastHyphenIndex) {
            phoneNumber = phoneNumber.substring(0, secondToLastHyphenIndex) + "-" + phoneNumber.substring(secondToLastHyphenIndex, phoneNumber.length());
        }
        //If the number starts with 1, add a dash after 1
        if (phoneNumber.startsWith("1")) {
            phoneNumber = phoneNumber.substring(0, 1) + "-" + phoneNumber.substring(1, phoneNumber.length());
        }

        return phoneNumber;
    }

    private static String removeNonnumeric(String text) {
        return text.replaceAll("[^\\d]", "");
    }
}