Question

因此，我应该让用户输入他们的姓名和号码，并将其添加到列表中并显示在ScrollView中。但是，我不知道在显示它的最后一步中还要做什么。我有一个Main，Contact和ContactsManager类。

Button      contactButton;
EditText    nameText;
EditText    numberText;
ScrollView  scrollView;

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

    contactButton = findViewById(R.id.button);
    nameText = findViewById(R.id.editTextName);
    numberText = findViewById(R.id.editTextNumber);
    scrollView = findViewById(R.id.scrollView);
    final ContactsManager contactsManager = new ContactsManager();

    contactButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String enterText;
            String enterNumber;

            enterText = nameText.getText().toString();
            enterNumber = numberText.getText().toString();

            contactsManager.createContact(enterText, enterNumber);

            scrollView.getDisplay();
        }
    });
}

public class Contact {
    private String name;
    private String phoneNumber;

    public Contact(String nName, String NPhoneNumber) {
        this.name = nName;
        this.phoneNumber = NPhoneNumber;
    }

    public Contact() {
    }

    public String getName() {
        return name;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }
}

public class ContactsManager {

    private ArrayList<Contact> contacts;

    public Contact createContact(String name, String phoneNumber) {
        Contact contact = new Contact();
        this.contacts = new ArrayList<>();
        return contact;
    }
}

当我单击创建联系人的按钮时，没有任何显示。

Answer 1

您没有将新联系人正确添加到联系人管理器中。尝试类似的东西：

public class ContactsManager {

    private List<Contact> contacts;

    public ContactsManager() {
        contacts = new ArrayList<>(); // Initialise the list once.
    }
    public Contact createContact(String name, String phoneNumber) {
        Contact contact = new Contact(name, phoneNumber);
        contacts.add(contact); // Add the new contact to the list
        return contact;
    }
    // Use this to access all your contacts
    public List<Contact> getContacts() {
        return contacts;
    }
}

完成此操作后，您需要将显示内容与联系人列表相关联。

如何将ArrayList <contact>联系人显示到ScrollView？

1 个答案: