Add the following method to check whether an email address is valid or not:

private boolean isValidEmailId(String email){
return Pattern.compile("^(([\\\\w-]+\\\\.)+[\\\\w-]+|([a-zA-Z]{1}|[\\\\w-]{2,}))@"
+ "((([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\\\\.([0-1]?"
+ "[0-9]{1,2}|25[0-5]|2[0-4][0-9])\\\\."
+ "([0-1]?[0-9]{1,2}|25[0-5]|2[0-4][0-9])\\\\.([0-1]?"
+ "[0-9]{1,2}|25[0-5]|2[0-4][0-9])){1}|"
+ "([a-zA-Z]+[\\\\w-]+\\\\.)+[a-zA-Z]{2,4})$").matcher(email).matches();
}

The above method can easily be verified by converting the text of an EditText widget into a String:

if(isValidEmailId(edtEmailId.getText().toString().trim())){
  Toast.makeText(getApplicationContext(), "Valid Email Address.", Toast.LENGTH_SHORT).show();
}else{       
  Toast.makeText(getApplicationContext(), "InValid Email Address.", Toast.LENGTH_SHORT).show();
}