rx-android - 在带有 JDK8 的 Android 上使用 RxJava2 启用登录按钮

Question

当用户名和密码足够长时，我想使用 RxJava2 启用登录按钮，但出现错误。

final Button loginButton = (Button) view.findViewById(R.id.loginbutton);
final TextView usernameField = (TextView) view.findViewById(R.id.username_logindialog);

Observable<Boolean> userNameValid = RxTextView.textChangeEvents(usernameField)
        .map(e -> e.text())
        .map(inputText -> inputText.length() > 4);

final TextView passwordField = (TextView) view.findViewById(R.id.password_logindialog);
Observable<Boolean> passwordValid = RxTextView.textChangeEvents(passwordField)
        .map(e -> e.text())
        .map(inputText -> inputText.length() > 7);

Observable<Boolean> registerEnabled =
        Observable.combineLatest(userNameValid, passwordValid, (a,b) -> a && b);
registerEnabled.registerObserver( enabled -> loginButton.setEnabled(enabled));

对于您看到的两个部分，map(inputText这是错误：

错误a && b是

还有其他错误，但我认为前两个错误是根本原因，但我不知道应该使用什么来代替Observable.combineLatest现在。

Answer 1

你可以用这个

emailChangeObservable = RxTextView.textChangeEvents(email);
passwordChangeObservable = RxTextView.textChangeEvents(password);

// force-disable the button
submitButton.setEnabled(false);

Observable.combineLatest(emailChangeObservable, passwordChangeObservable, 
                                        (emailObservable, passwordObservable) -> {
    boolean emailCheck = emailObservable.text().length() >= 3;
    boolean passwordCheck = passwordObservable.text().length() >= 3;
    return emailCheck && passwordCheck;
}).subscribe(aBoolean -> {
    submitButton.setEnabled(aBoolean);
});

// submit button will only be clickable if both forms have more than 3 characters each

检查这里的来源