Android EditText 银行卡 四位空一格

/**
 * 设置银行卡输入时每隔4位多一位空格
 */
public static void bankCardInput(final EditText editText) {
    //设置输入长度不超过24位(包含空格)
    editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(24)});
    editText.addTextChangedListener(new TextWatcher() {
        char space = ' ';
        //改变之前text长度
        int beforeTextLength = 0;
        //改变之前的文字
        private CharSequence beforeChar;
        //改变之后text长度
        int onTextLength = 0;
        //是否改变空格或光标
        boolean isChanged = false;
        // 记录光标的位置
        int location = 0;
        private char[] tempChar;
        private StringBuffer buffer = new StringBuffer();
        //已有空格数量
        int spaceNumberB = 0;

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            beforeTextLength = s.length();
            if (buffer.length() > 0) {
                buffer.delete(0, buffer.length());
            }
            spaceNumberB = 0;
            for (int i = 0; i < s.length(); i++) {
                if (s.charAt(i) == ' ') {
                    spaceNumberB++;
                }
            }
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            onTextLength = s.length();
            buffer.append(s.toString());
            if (onTextLength == beforeTextLength || onTextLength <= 3
                    || isChanged) {
                isChanged = false;
                return;
            }
            isChanged = true;
        }

        @Override
        public void afterTextChanged(Editable s) {
            if (isChanged) {
                location = editText.getSelectionEnd();
                int index = 0;
                while (index < buffer.length()) {
                    if (buffer.charAt(index) == space) {
                        buffer.deleteCharAt(index);
                    } else {
                        index++;
                    }
                }
                index = 0;
                int spaceNumberC = 0;
                while (index < buffer.length()) {
                    if ((index == 4 || index == 9 || index == 14 || index == 19)) {
                        buffer.insert(index, space);
                        spaceNumberC++;
                    }
                    index++;
                }

                if (spaceNumberC > spaceNumberB) {
                    location += (spaceNumberC - spaceNumberB);
                }

                tempChar = new char[buffer.length()];
                buffer.getChars(0, buffer.length(), tempChar, 0);
                String str = buffer.toString();
                if (location > str.length()) {
                    location = str.length();
                } else if (location < 0) {
                    location = 0;
                }

                editText.setText(str);
                Editable etable = editText.getText();
                Selection.setSelection(etable, location);
                isChanged = false;
            }
        }
    });
}