用户开始键入后如何在EditText中添加字符 [英] How to add a character in EditText after user starts typing

问题描述

我有一个editText，用户在其中输入电话号码，但是当他们单击其第一个数字时，我希望在文本的开头出现一个"+".我有此代码，但"+"一直存在.我只希望它在用户输入数字时显示，我该如何解决?

I have an editText where a user inputs a phone number, but right when they click their first number, I want a '+' to appear in the beginning of the text. I have this code but the '+' is constantly there. I only want it to appear when a user inputs a number, how would I fix this?

    final EditText editText = findViewById(R.id.register_edit_phone);
    final String prefix = "+";
    editText.setText(prefix);
    Selection.setSelection(editText.getText(), editText.getText().length());
    editText.addTextChangedListener(new TextWatcher() {

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

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

        @Override
        public void afterTextChanged(Editable s) {
            if (!s.toString().startsWith(prefix)) {
                editText.setText(prefix);
                Selection.setSelection(editText.getText(), editText.getText().length());
            }
        }
    });

推荐答案

    Pattern p = Pattern.compile("^\\d+.*");

editText.addTextChangedListener(new TextWatcher() {

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

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

        @Override
        public void afterTextChanged(Editable s) {
            if (p.matcher(s.toString().trim()).matches()) {
                editText.setText(prefix + s.toString());
            }
            Selection.setSelection(editText.getText(), editText.getText().length());
        }
    });

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