public static boolean isEmailValid(String email) {
    boolean isValid = false;

    String expression = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
    CharSequence inputStr = email;

    Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(inputStr);
    if (matcher.matches()) {
        isValid = true;
    }
    return isValid;
}

试试这个:

if (!emailRegistration.matches("[a-zA-Z0-9._-]+@[a-z]+\.[a-z]+")) {
 editTextEmail.setError("Invalid Email Address");
}

试试这个

public static final Pattern EMAIL_ADDRESS_PATTERN = Pattern.compile(

              "[a-zA-Z0-9\\+\\.\\_\\%\\-\\+]{1,256}" +
              "\\@" +
              "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}" +
              "(" +
              "\\." +
              "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25}" +
              ")+"
          );

并在编辑文本

final String emailText = email.getText().toString();
EMAIL_ADDRESS_PATTERN.matcher(emailText).matches()

Java:

public static boolean isValidEmail(CharSequence target) {
    return (!TextUtils.isEmpty(target) && Patterns.EMAIL_ADDRESS.matcher(target).matches());
}

科特林：

fun CharSequence?.isValidEmail() = !isNullOrEmpty() && Patterns.EMAIL_ADDRESS.matcher(this).matches()

编辑:它将在Android 2.2+以上工作!!

编辑:添加缺失;

public static boolean isEmailValid(String email) {
    boolean isValid = false;

    String expression = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
    CharSequence inputStr = email;

    Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(inputStr);
    if (matcher.matches()) {
        isValid = true;
    }
    return isValid;
}

要执行电子邮件验证，我们有许多方法，但最简单和最容易的方法是两种方法。

1-使用EditText(....)。addTextChangedListener保持触发在EditText框中的每个输入，即email_id无效或有效

/**
 * Email Validation ex:- tech@end.com
*/


final EditText emailValidate = (EditText)findViewById(R.id.textMessage); 

final TextView textView = (TextView)findViewById(R.id.text); 

String email = emailValidate.getText().toString().trim();

String emailPattern = "[a-zA-Z0-9._-]+@[a-z]+\\.+[a-z]+";

emailValidate .addTextChangedListener(new TextWatcher() { 
    public void afterTextChanged(Editable s) { 

    if (email.matches(emailPattern) && s.length() > 0)
        { 
            Toast.makeText(getApplicationContext(),"valid email address",Toast.LENGTH_SHORT).show();
            // or
            textView.setText("valid email");
        }
        else
        {
             Toast.makeText(getApplicationContext(),"Invalid email address",Toast.LENGTH_SHORT).show();
            //or
            textView.setText("invalid email");
        }
    } 
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    // other stuffs 
    } 
    public void onTextChanged(CharSequence s, int start, int before, int count) {
    // other stuffs 
    } 
}); 

2-使用if-else条件的最简单方法。使用getText()获取EditText框字符串，并与电子邮件提供的模式进行比较。如果图案不匹配或不匹配，点击按钮吐司消息。它不会在EditText框中的每个字符输入时触发。下面是一个简单的例子。

final EditText emailValidate = (EditText)findViewById(R.id.textMessage); 

final TextView textView = (TextView)findViewById(R.id.text); 

String email = emailValidate.getText().toString().trim();

String emailPattern = "[a-zA-Z0-9._-]+@[a-z]+\\.+[a-z]+";

// onClick of button perform this simplest code.
if (email.matches(emailPattern))
{
Toast.makeText(getApplicationContext(),"valid email address",Toast.LENGTH_SHORT).show();
}
else 
{
Toast.makeText(getApplicationContext(),"Invalid email address", Toast.LENGTH_SHORT).show();
}