Email and Password Validation in Open Event Android

The Open Event API Server exposes a well documented JSONAPI compliant REST API that can be used in The Open Even Android and Frontend. The Open Event API Server enables the Android and web clients to add the user authentication (sign up/login) in the project. In the process of signing up or logging in user it is needed to validate email and password entered by the user and show the error to give better user experience. In this post I explain how to validate email and password entered by the user using TextInputLayout.

1. Add TextInputLayout

TextInputLayout wraps an EditText (or descendant) to show a floating label when the hint is hidden due to the user inputting text. Add TextInputLayout for email field in the layout as given below.

<android.support.design.widget.TextInputLayout
            android:id="@+id/text_input_layout_email"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <android.support.v7.widget.AppCompatEditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/email"
                android:inputType="textEmailAddress" />
</android.support.design.widget.TextInputLayout>

Here the hint attribute is used to display hint in the floating label. Specify the input type so the system displays the appropriate soft input method (such as an on-screen keyboard) for the field. For email EditText we are using textEmailAddress input type. Similarly add TextInputLayout for the password field. The input type for the password is textPassword.

2.  Create and initialize object

Now in the activity create and initialize TextInputLayout and EditText objects for email and password.

@BindView(R.id.text_input_layout_email)
TextInputLayout mTextInputLayoutEmail;
@BindView(R.id.text_input_layout_password)
TextInputLayout mTextInputLayoutPassword;

@Override
protected void onCreate(Bundle savedInstanceState) {
    ButterKnife.bind(this);

    private AppCompatEditText mEditTextEmail = (AppCompatEditText) mTextInputLayoutEmail.getEditText();
    private AppCompatEditText mEditTextPassword = (AppCompatEditText) mTextInputLayoutPassword.getEditText();
}

Here we are using ButterKnife for binding views with fields. The getEditText() method returns the EditText view used for text input inside the TextInputLayout.

3.  Create validate() method

Create validate() method which takes two arguments. The first is email and the second password. It will return true if the email and password are valid else false.

private boolean validate(String email, String password) {

        // Reset errors.
        mTextInputLayoutEmail.setError(null);
        mTextInputLayoutPassword.setError(null);

        if (Utils.isEmpty(email)) {
            mTextInputLayoutEmail.setError("Email is required");
            return false;
        } else if (!Utils.isEmailValid(email)) {
            mTextInputLayoutEmail.setError("Enter a valid email");
            return false;
        }

        if (Utils.isEmpty(password)) {
            mTextInputLayoutPassword.setError("Password is required");
            return false;
        } else if (!Utils.isPasswordValid(password)) {
            mTextInputLayoutPassword.setError("Password must contain at least 6 characters");
            return false;
        }

        return true;
}

Here it first resets the error for the TextInputLayout by setting it to null. Then it checks email string if it is empty then it will show “Email is required” error using setError() method.

4.  Create isEmailValid() and isPasswordValid() method

Now create isEmailValid() and isPasswordvalid() method which is used by validate() method. The isEmailValid() method should take email string as an argument and return boolean indicating whether the email is valid or not. The isEmailValid() method uses Pattern and Matcher class to determine if the pattern of input is email or not. The isPasswordValid() method should take password string as an argument and return true if the password is satisfying minimum condition. Here in our case length of the password should be minimum 6.

public static boolean isEmailValid(String email){
        Pattern pattern = Patterns.EMAIL_ADDRESS;
        Matcher matcher = pattern.matcher(email);
        return matcher.matches();
}

//Check password with minimum requirement here(it should be minimum 6 characters)
public static boolean isPasswordValid(String password){
        return password.length() >= 6;
}

5.  Use validate() method

Now we are ready to use validate() method when signing up or logging in the user. The getText() method of EditText will return text input.

String email = mEditTextEmail.getText().toString();
String password = mEditTextPassword.getText().toString();

if (validate(email, password)) {
    //Sign up or login User
}

Conclusion

Using TextInputLayout with floating hint label and error handling gives awesome UI and UX.