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UserNameYo
Asked: 2020-05-30 12:24:24 +0800 CST 2020-05-30 12:24:24 +0800 CST

Only allow writing an email in EditText

  • 772

I have made this code to try that EditTextEmailyou can only write an email if you write something that is not an email send aToast

    EditText EditTextEmail;
    Button btn1;

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

        btn1 = (Button) findViewById(R.id.btn1);

        EditTextEmail = (EditText) findViewById(R.id.EditTextEmail);
        final String compruebaemail = EditTextEmail.getEditableText().toString().trim();


        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (!compruebaemail.matches("[a-zA-Z0-9._-]+@[a-z]+.[a-z]+"))
                {
                Toast.makeText(MainActivity.this, "Por favor, introduce bien su email", Toast.LENGTH_LONG).show();
                }
            }
        });
    }
}

The problem is basically that I write what I write my commands Toastas if I were writing badly.

Example of text with which it fails:

[email protected]
java

3 Answers

  1. Best Answer

    The variable compruebaemailis being assigned in onCreate, before you enter the text.

    On the other hand, if it is assigned within the event onClick, only then will it have the last value entered.

    btn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        final String compruebaemail = EditTextEmail.getEditableText().toString().trim();

        final String regex = "(?:[^<>()\\[\\].,;:\\s@\"]+(?:\\.[^<>()\\[\\].,;:\\s@\"]+)*|\"[^\\n\"]+\")@(?:[^<>()\\[\\].,;:\\s@\"]+\\.)+[^<>()\\[\\]\\.,;:\\s@\"]{2,63}";

        if (!compruebaemail.matches(regex))
        {
            Toast.makeText(MainActivity.this, "Por favor, introduce bien su email", Toast.LENGTH_LONG).show();
        }
    }
});

    Note that I opted for another regular expression, taken from the answer to my question: Validating an email in JavaScript .

    The problem that the regular expression you were using could have was that:

    • dot had to be escaped (if it doesn't match any character)

    • you had to allow more than 1 point (example [email protected])

    • possibly allow case in the domain (since you were only allowing [a-z], and regular expressions are case sensitive by default)

    • and allow other characters, valid in any e-mail (example: +).

    The regex I used does not apply to all valid emails, but in my opinion it will work for most cases. In fact, if all valid cases according to the RFC were really to be accepted, you would be accepting " aberrations " that one would normally not want to accept in a form. However, email validation is too broad a topic to be beyond the scope of this question.

    • 8

  2. You can perform validation using a TextInputLayoutand use method setError()to define the message, setErrorEnabled()to enable it, for example:

    //Validación de error en email, valida texto que ingresa el usuario en el EditText.
boolean emailError = validaEditTextEmail();

//Dependiendo del valor booleando al validar el email, muestra el mensaje:
TextInputLayout tilEmail = (TextInputLayout) rootView.findViewById(R.id.til_email);
tilEmail.setError(emailError ? "Ingrese un correo válido" : "");
tilEmail.setErrorEnabled(emailError);

    When the validation detects an incorrect email, the error message is enabled:

    enter image description here

    I add an example of TextInputLayoutfor the previous example:

    <android.support.design.widget.TextInputLayout
    android:id="@+id/til_email"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="10dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:paddingTop="5dp"
    android:paddingLeft="5dp"
    android:paddingRight="5dp">

    <EditText
        android:id="@+id/mi_email"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/preg_correo"
        android:inputType="textEmailAddress"
        android:textSize="16sp"/>
</android.support.design.widget.TextInputLayout>

    In this example, the validation is performed on the text entered in the EdiTextwith id mi_email, based on the value obtained we determine whether or not to show the message through the TextInputLayout.

    • 3

  3. Since android version 2.2+ there is this method:

    public final static boolean esEmailValido(CharSequence email) {
   if (email== null) {
       return false;
   } else {
       return android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches();
   }
}

    If you want an alternative, I propose the following:

    public static boolean esEmailValido(String email) {
    String expresiones = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
    Pattern pattern = Pattern.compile(expresiones, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(email);
    return matcher.matches();
}

    The implementation in your code would be as follows:

    EditText EditTextEmail;
Button btn1;

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

    btn1 = (Button) findViewById(R.id.btn1);

    EditTextEmail = (EditText) findViewById(R.id.EditTextEmail);
    final String compruebaemail = EditTextEmail.getEditableText().toString().trim();


    btn1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (!esEmailValido(compruebaemail))
            {
            Toast.makeText(MainActivity.this, "Por favor, introduce bien su email", Toast.LENGTH_LONG).show();
            }
        }
    });
}

    public static boolean esEmailValido(String email) {
        String expresiones = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
        Pattern pattern = Pattern.compile(expresiones, Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(email);
        return matcher.matches();
    }

}

    If you wanted to use the first method, it would be exactly the same way.

    • 2