變量「studentNumber」和「passWord」可能沒有被初始化？

Question

public class LoginActivity extends AppCompatActivity implements View.OnClickListener { 

public EditText studentNumber, passWord; 
//defining AwesomeValidation object 
public AwesomeValidation awesomeValidation; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_login); 

    awesomeValidation = new AwesomeValidation(ValidationStyle.BASIC); 
    studentNumber = (EditText) findViewById(R.id.studentNumber); 
    passWord = (EditText) findViewById(R.id.passWord); 

    awesomeValidation.addValidation(this, R.id.studentNumber, "^[0-9]{9}", R.string.studentnumberError); 
    String regexPassword = ".{8,}"; 
    awesomeValidation.addValidation(this, R.id.passWord, regexPassword, R.string.invalid_password); 

    signIn.setOnClickListener(this); 
} 

// Triggers when LOGIN Button clicked 
@Override 
public void onClick(View view) { 
    if (view == signIn) { 
     checkLogin(); 
    } 
} 

public void checkLogin() { 

    // Get text from studentNumber and passWord field 
    final String studentNumber = studentNumber.getText().toString(); 
    final String passWord = passWord.getText().toString(); 

    // Initialize AsyncLogin() class with studentNumber and password 
    new AsyncLogin().execute(studentNumber,passWord); 

    } 
} 

Android Studio說變量studentNumber和passWord可能沒有被初始化。錯誤顯示在此行上：

final String studentNumber = studentNumber.getText().toString(); 
final String passWord = passWord.getText().toString(); 

什麼似乎是問題？這是表單的驗證嗎？謝謝。

Answer 1

你越來越錯誤，因爲字符串名稱和姓名的EditText是樣品，請改變你的方法是這樣的。

public void checkLogin() { 

    // Get text from studentNumber and passWord field 
    final String studentNum = studentNumber.getText().toString(); 
    final String pass= passWord.getText().toString(); 

    // Initialize AsyncLogin() class with studentNumber and password 
    new AsyncLogin().execute(studentNum,pass); 

    } 

Answer 2

你會得到變量「studentNumber」和「passWord」可能沒有被初始化？

，因爲你的字符串變量的名字和編輯文本的名字都是相同的，所以它們是相互矛盾的

只是改變你的字符串變量名

使用本

final String studentNumber2 = studentNumber.getText().toString(); 
final String passWord2 = passWord.getText().toString(); 

而不是這個

final String studentNumber = studentNumber.getText().toString(); 
final String passWord = passWord.getText().toString(); 

Answer 3

中的onClick方法更改字符串變量的名字，這是相互矛盾與EditText上的變量名：

public void checkLogin() { 

// Get text from studentNumber and passWord field 
final String studentNumberString = studentNumber.getText().toString(); 
final String passWordString = passWord.getText().toString(); 

// Initialize AsyncLogin() class with studentNumber and password 
new AsyncLogin().execute(studentNumberString,passWordString); 

} 
}