验证只允许在android中编辑文本中的数字和字符

Question

在我的应用程序中,我必须验证edittext.它应该只允许字符,数字,下划线和hypen.

这是我的代码:

edittext.addTextChangedListener(new TextWatcher() {

                        @Override
                        public void onTextChanged(CharSequence s, int start, int before, int count) {
                            // TODO Auto-generated method stub

                            }

                        @Override
                        public void beforeTextChanged(CharSequence s, int start, int count,
                        int after) {
                                            // TODO Auto-generated method stub

                            }

                                        @Override
                            public void afterTextChanged(Editable s) {
                                            // validation codes here

                            location_name=s.toString();
                            Toast.makeText(getApplicationContext(),location_name, Toast.LENGTH_SHORT).show();                

                            if (location_name.matches(".*[^a-z^0-9].*")) 
                                {
                            location_name = location_name.replaceAll("[^a-z^0-9]", "");
                            s.append(location_name);
                            s.clear();
                            Toast.makeText(getApplicationContext(),"Only lowercase letters and numbers are allowed!",Toast.LENGTH_SHORT).show();

                            }

                            }

                        });     

location.add(location_name);

在此,当我在edittext中输入输入时,应用程序被强制关闭.请给我建议.谢谢.

Answer 1

Android中有一些非常简单的东西,而不是使用"手动"检查方法:

InputFilter filter = new InputFilter() { 
    public CharSequence filter(CharSequence source, int start,
                               int end, Spanned dest, int dstart, int dend) { 

        for (int i = start;i < end;i++) { 
            if (!Character.isLetterOrDigit(source.charAt(i)) && 
                !Character.toString(source.charAt(i)).equals("_") && 
                !Character.toString(source.charAt(i)).equals("-")) 
            { 
                return ""; 
            } 
        } 
        return null; 
    } 
}; 

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

或者另一种方法:在创建EditText的XML中设置允许的字符:

<EditText 
  android:inputType="text" 
  android:digits="0,1,2,3,4,5,6,7,8,9,*,qwertzuiopasdfghjklyxcvbnm,_,-" 
  android:hint="Only letters, digits, _ and - allowed" />

Answer 2

<EditText 
  android:inputType="text" 
  android:digits="0,1,2,3,4,5,6,7,8,9,*,qwertzuiopasdfghjklyxcvbnm,_,-" 
  android:hint="Only letters, digits, _ and - allowed"
/>

以上代码还将包括,避免,使用以下代码

<EditText 
  android:inputType="text" 
  android:digits="0123456789qwertzuiopasdfghjklyxcvbnm_-"
  android:hint="Only letters, digits, _ and - allowed"
/>

Answer 3

这可能很有用,特别是如果你的EditText应该允许变音符号(在我的情况下,葡萄牙语变音符号):

<EditText
   android:digits="0123456789AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZzÁáÂâÃãÀàÇçÉéÊêÍíÓóÔôÕõÚú"
/>

Answer 4

类似于 的解决方案android:digits="0123456789*"是使用：

EditText etext = new EditText(this);
etext.setKeyListener(DigitsKeyListener.getInstance("0123456789*"));

一个额外的好处是它还显示数字键盘。