防止EditText接受特殊字符

InputFilter filter = new InputFilter() {
    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        Pattern pattern = Pattern.compile("[a-zA-Z0-9]+"); // 允许输入字母和数字
        Matcher matcher = pattern.matcher(source);
        if (!matcher.matches()) {
            return "";
        }
        return null;
    }
};

editText.setFilters(new InputFilter[]{filter});

editText.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        String input = s.toString();
        if (containsSpecialCharacters(input)) {
            editText.setText(removeSpecialCharacters(input));
            editText.setSelection(editText.getText().length()); // 将光标移至末尾
            Toast.makeText(MainActivity.this, "不允许输入特殊字符", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void afterTextChanged(Editable s) {
    }
});

private boolean containsSpecialCharacters(String input) {
    Pattern pattern = Pattern.compile("[^a-zA-Z0-9]");
    Matcher matcher = pattern.matcher(input);
    return matcher.find();
}

private String removeSpecialCharacters(String input) {
    return input.replaceAll("[^a-zA-Z0-9]", "");
}