java - 我的类(class)中可以包含哪些代码行，以便对电子邮件和密码进行验证？

Question

我已经编写了以下代码行，我需要在其中包含电子邮件和密码的错误验证检查。错误的邮件/密码输入时屏幕上的输出应采用 Toast.makeText() 格式。所以这是下面的代码

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    public void clickRegister(View view) {

        startActivity(new Intent(MainActivity.this, RegisterActivity.class));

    }

    private Button buttonSignin;
    private EditText emailAdd;
    private EditText passAdd;
    private FirebaseAuth firebaseAuth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        firebaseAuth=FirebaseAuth.getInstance();
        if(firebaseAuth.getCurrentUser()!=null){
            //Remote control activity
            finish();
            startActivity(new Intent(getApplicationContext(),RemoteControl.class));
        }
        buttonSignin = (Button) findViewById(R.id.logIn);
        emailAdd = (EditText) findViewById(R.id.emailAddress);
        passAdd = (EditText) findViewById(R.id.passWord);

        buttonSignin.setOnClickListener(this);


    }
private void userLogin(){
        String email=emailAdd.getText().toString().trim();
        String password=passAdd.getText().toString().trim();
    if(TextUtils.isEmpty(email)){
        //Email is empty!
        Toast.makeText(this,"Please Enter Email",Toast.LENGTH_SHORT).show();
        //Stop function from executing further
        return;
    }

    if (TextUtils.isEmpty(password))
    {
        //Password is empty
        Toast.makeText(this,"Please Enter Password",Toast.LENGTH_SHORT).show();
        return;
    }


    firebaseAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
        @Override
        public void onComplete(@NonNull Task<AuthResult> task) {
            if(task.isSuccessful()){
                //start profile activity
                finish();
                startActivity(new Intent(getApplicationContext(),RemoteControl.class));
            }
        }
    });
}
    @Override
    public void onClick(View view) {
        if(view==buttonSignin)
        {
            userLogin();
        }

    }
}

我希望以 Toast.maketext() 的形式为每一行错误输入输出 Incorrect Email 和 Incorrect password

Answer 1

根据 Firebase Auth documentation , firebase 抛出一个 FirebaseAuthException 错误。 您在这里寻找的子类是:

• FirebaseAuthInvalidCredentialsException - 如果密码不正确
• FirebaseAuthInvalidUserException - 如果帐户不存在

并将其应用为:

firebaseAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
    @Override
    public void onComplete(@NonNull Task<AuthResult> task) {
        if(task.isSuccessful()){
            //start profile activity
            finish();
            startActivity(new Intent(getApplicationContext(),RemoteControl.class));
        }

      else if(task.getException() instanceof 
             FirebaseAuthInvalidCredentialsException){
        Toast.makeText(context, "wrong password", Toast.LENGTH_SHORT).show();
    }else if(task.getException() instanceof FirebaseAuthInvalidUserException){
        Toast.makeText(context, "no user with such email", Toast.LENGTH_SHORT).show();
    }
    }
});

但是如前所述，您不想通知您的用户电子邮件不存在，而只是在电子邮件格式错误时通知他们，为此您可以使用如下正则表达式模式:

if(TextUtils.isEmpty(email)){
    //Email is empty!
    Toast.makeText(this,"Please Enter Email",Toast.LENGTH_SHORT).show();
    //Stop function from executing further
    return;
}
else if (!Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
    Toast.makeText(context,"Email is badly formatted",Toast.LENGTH_SHORT).show();
}