属性更改时 UI 不更新

Question

当我从 MainActivity 更新 LoginViewModel 中的 User 属性时，我的 UI 没有改变。（卡在这个问题上 2 天了，找不到解决方案）

我的 User 类扩展了 BaseObservable（添加了 @Bindable 和 notificationPropertyChanged()），但我不知道我还应该做什么。

这些是课程：

用户：

public class User extends BaseObservable {

    protected String  userName;

    protected String lastName;

    public User(String userName, String lastName) {

        this.userName = userName;

        this.lastName = lastName;

        notifyPropertyChanged(BR._all);

    }

    @Bindable

    public String getUserName() {

        return userName;

    }

    public void setUserName(String userName) {

        this.userName = userName;

        notifyPropertyChanged(BR.userName);

    }

    @Bindable

    public String getLastName() {

        return lastName;

    }

    public void setLastName(String lastName) {

        this.lastName = lastName;

        notifyPropertyChanged(BR.lastName);

    }

}

视图模型：

public class LoginViewModel extends ViewModel {

    private User user;

    public LoginViewModel() {

        user = new User("Pero","Peric");

    }

    public User getUser() {

        return user;

    }

    public void setUser(User user) {

        this.user = user;

    }

    public String getUserName()

    {

        return user.getUserName();

    }

    public void setUserName(String userName)

    {

        user.setUserName(userName);

    }

    public String getLastName()

    {

        return user.getLastName();

    }

    public void setLastName(String lastName)

    {

        user.setUserName(lastName);

    }

}

Answer 1

问题是我：a)hadnt implement Observerble interface to ViewModel(I susspect that DataBinding     adds/removes his listener through that methods)b)made get methods @Bindable,and notify notifyPropertyChanged() in seters,c)add property in ViewModel of type PropertyChangeRegistryd)add notifyPropertyChanged(int fieldID) method视图模型：public class LoginViewModel extends ViewModel implements Observable {    private User user;    private PropertyChangeRegistry callbacks;    public LoginViewModel() {        user = new User("Karlo","maricevic");        callbacks = new PropertyChangeRegistry();    }    public User getUser() {        return user;    }    public void setUser(User user) {        this.user = user;    }    @Bindable    public String getUserName()    {        return user.getUserName();    }    public void setUserName(String userName)    {        user.setUserName(userName);        notifyPropertyChanged(BR.userName);    }    @Bindable    public String getLastName()    {        return user.getLastName();    }    public void setLastName(String lastName)    {        user.setUserName(lastName);    }    @Override    public void addOnPropertyChangedCallback(OnPropertyChangedCallback callback) {        callbacks.add(callback);    }    @Override    public void removeOnPropertyChangedCallback(OnPropertyChangedCallback callback) {        //callbacks.remove(callback);    }    void notifyPropertyChanged(int fieldId)    {        callbacks.notifyCallbacks(this,fieldId,null);    }}PS：在这个例子的小实验之后，你不需要用户扩展 BaseObservable 来从 ViewModel 更新 UI