在android中的编辑文本中格式化信用卡

问题描述

如何让EditText接受格式输入:

4digit 4digit 4digit 4digit

我试过

github.com 上的示例

迟到的答案，但我想它可能对某人有帮助:

Late answer, but I guess it may helpful for somebody:

    cardNumberEditText.addTextChangedListener(new TextWatcher() {

        private static final int TOTAL_SYMBOLS = 19; // size of pattern 0000-0000-0000-0000
        private static final int TOTAL_DIGITS = 16; // max numbers of digits in pattern: 0000 x 4
        private static final int DIVIDER_MODULO = 5; // means divider position is every 5th symbol beginning with 1
        private static final int DIVIDER_POSITION = DIVIDER_MODULO - 1; // means divider position is every 4th symbol beginning with 0
        private static final char DIVIDER = '-';

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            // noop
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            // noop
        }

        @Override
        public void afterTextChanged(Editable s) {
            if (!isInputCorrect(s, TOTAL_SYMBOLS, DIVIDER_MODULO, DIVIDER)) {
                s.replace(0, s.length(), buildCorrectString(getDigitArray(s, TOTAL_DIGITS), DIVIDER_POSITION, DIVIDER));
            }
        }

        private boolean isInputCorrect(Editable s, int totalSymbols, int dividerModulo, char divider) {
            boolean isCorrect = s.length() <= totalSymbols; // check size of entered string
            for (int i = 0; i < s.length(); i++) { // check that every element is right
                if (i > 0 && (i + 1) % dividerModulo == 0) {
                    isCorrect &= divider == s.charAt(i);
                } else {
                    isCorrect &= Character.isDigit(s.charAt(i));
                }
            }
            return isCorrect;
        }

        private String buildCorrectString(char[] digits, int dividerPosition, char divider) {
            final StringBuilder formatted = new StringBuilder();

            for (int i = 0; i < digits.length; i++) {
                if (digits[i] != 0) {
                    formatted.append(digits[i]);
                    if ((i > 0) && (i < (digits.length - 1)) && (((i + 1) % dividerPosition) == 0)) {
                        formatted.append(divider);
                    }
                }
            }

            return formatted.toString();
        }

        private char[] getDigitArray(final Editable s, final int size) {
            char[] digits = new char[size];
            int index = 0;
            for (int i = 0; i < s.length() && index < size; i++) {
                char current = s.charAt(i);
                if (Character.isDigit(current)) {
                    digits[index] = current;
                    index++;
                }
            }
            return digits;
        }
    });

这与开始字符串/结束字符串/中间字符串编辑完美配合，粘贴也完美工作.

this works perfectly with start-string/end-string/mid-string editing, also paste works perfectly.

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