Prerequisite: EditText widget in Android using Java with Examples
Email validation is required to inform the user that the Email entered by the user is not in a valid format. If the user has not entered the Email in the wrong format then the error filed is to be given for the EditText. In this article, it’s been discussed how to implement the Email validator in Android step by step. Have a look at the following image to get an idea of what’s been discussed in this article. Note that we are going to implement this project using the Java language.
Steps to Implement the Email Validator in Android
Step 1: Create an empty activity project
- Create an empty activity Android Studio project. Select Java as a programming language.
- To know how to create an empty activity Android Studio project refer to Android | How to Create/Start a New Project in Android Studio?.
Step 2: Working with the activity_main.xml file
- In the main layout of the application, only two of the widgets are implemented. One is the Email EditText field and one Button which when clicked the entered email is to be checked.
- Invoke the following code in the activity_main.xml file to implement the UI layout.
XML
<?xml version="1.0" encoding="utf-8"?><RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" tools:ignore="HardcodedText"> <!--EditText which takes input as Email from the user--> <EditText android:id="@+id/emailField" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginStart="16dp" android:layout_marginTop="64dp" android:layout_marginEnd="16dp" android:drawableStart="@drawable/ic_email_black_24dp" android:drawablePadding="12dp" android:hint="Email" /> <!--Button which when clicked validates the entered email is valid or not--> <Button android:id="@+id/validateButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/emailField" android:layout_marginStart="16dp" android:layout_marginTop="16dp" android:layout_marginEnd="16dp" android:backgroundTint="@color/colorPrimary" android:text="VALIDATE" android:textColor="@android:color/white" /></RelativeLayout> |
Output UI:
Step 3: Working with the MainActivity.java file
- In this case, the pattern EMAIL_ADDRESS is used for demonstration purposes.
- However, there are 5 more patterns to get validate the input from the user. Those are:
DOMAIN_NAME, IP_ADDRESS, PHONE, TOP_LEVEL_DOMAIN, WEB_URL.
- Refer to the Patterns for more information about the predefined patterns in Android.
- Invoke the following code inside the MainActivity.java file to implement the Email Validator in this case. Comments are added for a better understanding.
Java
import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.util.Patterns;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends AppCompatActivity { // EditText filed for Email EditText etMail; // Button to validate the Email address Button bValidate; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // register all the UI elements // with their appropriate IDs etMail = findViewById(R.id.emailField); bValidate = findViewById(R.id.validateButton); // handle the VALIDATE button to show the toast // message whether the entered email is valid or not bValidate.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { emailValidator(etMail); } }); } // the function which triggered when the VALIDATE button is clicked // which validates the email address entered by the user public void emailValidator(EditText etMail) { // extract the entered data from the EditText String emailToText = etMail.getText().toString(); // Android offers the inbuilt patterns which the entered // data from the EditText field needs to be compared with // In this case the entered data needs to compared with // the EMAIL_ADDRESS, which is implemented same below if (!emailToText.isEmpty() && Patterns.EMAIL_ADDRESS.matcher(emailToText).matches()) { Toast.makeText(this, "Email Verified !", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(this, "Enter valid Email address !", Toast.LENGTH_SHORT).show(); } }} |
Kotlin
// Kotlin code for email validatorpackage com.example.gfgemailvalidatorimport android.graphics.Colorimport android.graphics.drawable.ColorDrawableimport android.os.Bundleimport android.util.Patternsimport android.view.Viewimport android.widget.EditTextimport android.widget.Toastimport androidx.appcompat.app.ActionBarimport androidx.appcompat.app.AppCompatActivityclass MainActivity : AppCompatActivity() { private lateinit var myeditText: EditText private lateinit var email: String override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) // registering IDs for views myeditText = findViewById(R.id.tt) email = myeditText.text.toString().trim() } fun check(view: View) { // Getting the user input var text1 = myeditText?.text if(text1.isEmpty()) // check if user have not entered then ask for enter { Toast.makeText(this@MainActivity,"enter your email id",Toast.LENGTH_LONG).show() } else { if (Patterns.EMAIL_ADDRESS.matcher(text1).matches()) { // using EMAIL_ADREES matcher Toast.makeText(this@MainActivity, "MATCH", Toast.LENGTH_LONG).show() } else { Toast.makeText(this@MainActivity, "NO MATCH", Toast.LENGTH_LONG).show() } } }} |
