Drop Down List or Spinner With Model

1. Model

public class User {
    private int id;
    private String Name;
    private String Email;
    private int Age;

    public User(int id, String name, String email, int age) {
        this.id = id;
        Name = name;
        Email = email;
        Age = age;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getEmail() {
        return Email;
    }

    public void setEmail(String email) {
        Email = email;
    }

    public int getAge() {
        return Age;
    }

    public void setAge(int age) {
        Age = age;
    }

    @Override
    public String toString() {
        return  id + " : " + Name;

    }
}

2. Main Activity

public class MainActivity extends AppCompatActivity {
    //define variable
    private Spinner spinner;
    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //assign variagle
        spinner = findViewById(R.id.spinner1);
        button = findViewById(R.id.button1);

        //populate list
        List<User> userList = new ArrayList<>();
        userList.add(new User(1, "Ram", "ram@gamil.com", 40));
        userList.add(new User(2, "Shyam", "shyam@gamil.com", 45));
        userList.add(new User(3, "Ram Kumar", "ramkumar@gamil.com", 32));
        userList.add(new User(4, "Manoj Sing", "manoj@gamil.com", 56));

        //define and assing array adapter
        ArrayAdapter<User> adapter = new ArrayAdapter<User>(this,
                android.R.layout.simple_spinner_item, userList);

        //Assign adapter drop down list
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        //assign into spinner
        spinner.setAdapter(adapter);

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                User user = (User) adapterView.getSelectedItem();
                DisplayUserData(user);
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });

    }

    public void on_btn_submit(View view) {
        User user = (User) spinner.getSelectedItem();
        DisplayUserData(user);
    }

    private void DisplayUserData(User user) {
        int id = user.getId();
        String name = user.getName();
        String email = user.getEmail();
        int age = user.getAge();

        String sql = "";
        sql += "\nID : " + id;
        sql += "\nName : " + name;
        sql += "\nEmail : " + email;
        sql += "\nAge : " + age;

        Toast.makeText(MainActivity.this, ""+sql, Toast.LENGTH_SHORT).show();
    }

}