@Override
   public void onClick(DialogInterface dialog, int which) {
    SharedPreferences pref = getSharedPreferences("LOGIN3",
      MODE_PRIVATE);
    final EditText idtext = (EditText) findViewById(R.id.loginid);
    final EditText pwtext = (EditText) findViewById(R.id.loginpw);
    final String username = pref.getString("data1", null);
    final String userpassword = pref.getString("data2", null);
    Log.i("exp", pref.getString("data1", ""));
    Log.d("exp", pref.getString("data2", ""));
    try {
     if (username.equalsIgnoreCase(idtext.getText().toString())      //여기 워닝이 잡히는데용.... ㅠ_ㅠ 못잡겟어요
       && userpassword.equalsIgnoreCase(pwtext.getText()
         .toString())) {
      Toast.makeText(TabLayoutActivity.this, "로그인성공",
        Toast.LENGTH_SHORT).show();
     } else {
      Toast.makeText(TabLayoutActivity.this, "로그인 실패",
        Toast.LENGTH_SHORT).show();
     }
    } catch (Exception e) {
     e.printStackTrace();
    }
   }
 
 
 
05-30 03:16:12.887: W/System.err(990): java.lang.NullPointerException
05-30 03:16:12.887: W/System.err(990):  at com.tabactivity.TabLayoutActivity$2.onClick(TabLayoutActivity.java:116)