android - 在android中自定义editext输入

Question

如何自定义给定图中显示的 editext 的输入类型。基本上我的要求是 edittext 应该只显示最后 3 位或 4 位数字，只有最初的 12 位数字应该处于密码模式。

Answer 1

您需要添加一个TextWatcher到EditText：

int characterCount = 0;
int asteriskCount = 0;
CharSequence input = null;
input.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        characterCount = count;
        //update input sequence based on changes.
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        //update input sequence based on changes.
    }

    @Override
    public void afterTextChanged(Editable s) {
        if (asteriskCount != characterCount) {
            //make the visible sequence here.
            CharSequence seq = "";
            for (int i = 0; i < (characterCount <= 12 ? characterCount : 12); i++) {
                seq = seq + "*";
            }
            if (characterCount > 12) {

                for (int i = 12; i < characterCount; i++) {
                    seq = seq + characterCount.charAt(i);
                }
            }
            asteriskCount = characterCount;
            input.setText(seq);
        }
    }
});

Answer 2

没有这样的内置功能。所以你必须自己做。更改文本时，您必须对文本进行更改。这样做。

如果您通过扩展创建自定义 editText，EditText则可以覆盖onTextChanged方法并处理更改。

或者您可以使用TextWatcher来处理更改。

因此，当文本更改时，将除最后 3 位以外的数据设置为 *。

但请记住，您必须使用 String 字段将原始数据存储在字段中。

Answer 3

下面是我的 TextWatcher 的代码片段：

        private boolean spaceDeleted;
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            characterCount = start;
            //update input sequence based on changes.

        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
             // check if a space was deleted
            CharSequence charDeleted = s.subSequence(start, start + count);
            spaceDeleted = " ".equals(charDeleted.toString());

        }

        @Override
        public void afterTextChanged(Editable s) {
            if(s.length()>12){
                return;
                }
            System.out.println("Character Count in afterTextChange->"+characterCount);
            System.out.println("Editable Character->"+s);
            ccNumber.removeTextChangedListener(this);
             // record cursor position as setting the text in the textview
            // places the cursor at the end
            int cursorPosition = ccNumber.getSelectionStart();
            String withSpaces = formatText(s);
            ccNumber.setText(withSpaces);
            // set the cursor at the last position + the spaces added since the
            // space are always added before the cursor
            ccNumber.setSelection(cursorPosition + (withSpaces.length() - s.length()));

            // if a space was deleted also deleted just move the cursor
            // before the space
            if (spaceDeleted) {
                ccNumber.setSelection(ccNumber.getSelectionStart() - 1);
                spaceDeleted = false;
            }

            // enable text watcher
            ccNumber.addTextChangedListener(this);



        }

        private String formatText(CharSequence s) {
            // TODO Auto-generated method stub

            StringBuilder formatted = new StringBuilder();
            int count = 0;
            /* if(s.length()<12){
                formatted.append("*");
            }else{
                formatted.append(s.charAt(characterCount));
            }*/
            for (int i = 0; i < s.length(); ++i)
            {

                formatted.append("*");

                /*if (Character.isDigit(s.charAt(i)))
                {
                    if (count % 4 == 0 && count > 0)
                        formatted.append(" ");
                    formatted.append(s.charAt(i));
                    ++count;
                }*/
            }
            return formatted.toString();
        }
    });