Iam creating a simple login screen to change the activity as a practice even all of my code is right but when I click the button nothing happens neither the IF is true nor false

public class MainActivity extends AppCompatActivity {

private EditText name;
private EditText password;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    name = findViewById(R.id.username);
    password = findViewById(R.id.password);
    Button login = findViewById(R.id.login);
    
    login.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Login(name.getText().toString(),password.getText().toString());
        }
    });

}

private void Login(String username,String password) {

    if((username == ("Santos")) && (password == "1234")) {
        Intent intent = new Intent(MainActivity.this, MainActivity2.class);
        startActivity(intent);
    }
}}

note: the button itself works without the IF function

CodePudding user response：

Your login method compares strings by their object references. You have to compare them by their values.

When you call getText(), you will have a string object created with another object reference.

String name = "Santos"; // is object #7890
// Let's say username from getText() is object #4758

// will be always false
if (username == "Santos") {}

Check out the code below.

public class StringCompare {

   public void login(String username, String password) {
      if (username.equals("Santos") && password.equals("1234")) {
         System.out.println("Login successful");
      } else {
         System.out.println("Login failed");
      }

      if (username == "Santos" && password == "1234") {
         System.out.println("Login successful with reference check");
      } else {
         System.out.println("Login failed at reference check");
      }

      System.out.println();
   }

   public void testLogin(){
      String password = "1234";
      String username = "Santos";

      // creating another string object
      String anotherString = new String("Santos"); 

      // also creating another string object
      String something = new StringBuilder("Santos").toString();

      login(username, password);
      login(anotherString, password);
      login(something, password);
   }
}