这段使用parse.com数据库存储数据的Android代码有什么问题

Question

String nametxt;
String bloodtxt;
String agetxt;
String mobiletxt;
Button register;
EditText name;
EditText age;
EditText blood;
EditText mobile;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);
    name = (EditText) findViewById(R.id.name);
    age = (EditText) findViewById(R.id.age);
    blood = (EditText)findViewById(R.id.blood);
    age = (EditText)findViewById(R.id.age);
    register =(Button)findViewById(R.id.register);
    register.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            nametxt = name.getText().toString();
            agetxt = age.getText().toString();
            bloodtxt = blood.getText().toString();//logcat pointing exception here//
            mobiletxt = mobile.getText().toString();
            if (nametxt.equals("") && agetxt.equals("")) {
                Toast.makeText(getApplicationContext(),
                        "Please complete the sign up form",
                        Toast.LENGTH_LONG).show();
            }
            else
            {
                ParseUser user = new ParseUser();
                user.setUsername(nametxt);
                user.setPassword(agetxt);
                user.put("blood", bloodtxt);
                user.put("Mobile",mobiletxt);
                user.signUpInBackground(new SignUpCallback() {
                    @Override
                    public void done(ParseException e) {
                        if (e == null) {
                            Toast.makeText(getApplicationContext(), "Succesfully registered", Toast.LENGTH_LONG).show();
                        } else {
                            Toast.makeText(getApplicationContext(), "hey %d you are already registered in blood database.." + nametxt, Toast.LENGTH_LONG).show();


                        }
                    }
                });
            }

        }
    });

}

Answer 1

  mobile.getText().toString();