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使用RxJava2对ViewModel进行EditText验证

rx-binding rx-java2 rx-android android

davisjp · 技术社区 · 7 年前

我试图在单击按钮时使用RxJava对EditText执行验证,但我很难将验证移到ViewModel,这将使测试更容易。我正在使用Jake Wharton提供的RxBindings来获取UI输入和RxJava2的可流动性。当我单击AlertDialog上的按钮时,将ElateTest与PublishSubject组合以触发Flowable。以下是我目前得到的信息:

private Flowable<CharSequence> projectTitleObservable;
private final PublishSubject<CharSequence> createProjectClicked = PublishSubject.create();

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    final Context context = getActivity();

    View dialogView = LayoutInflater.from(context).inflate(R.layout.new_project, null);

    ButterKnife.bind(this, dialogView);

    projectTitleObservable = RxTextView.textChanges(projectNameEditText).toFlowable(BackpressureStrategy.LATEST);

    ConnectableFlowable <CharSequence> connectableFlowable = Flowable.combineLatest(createProjectClicked.toFlowable(BackpressureStrategy.LATEST), projectTitleObservable, (ignored, title) -> {
        boolean validTitle = !TextUtils.isEmpty(title);
        if (!validTitle) {
            projectNameEditText.setError("Project must have a name");
        }

        Timber.d("Hey, lambdas work! Look -> " + title);
        return title;
    })
            .publish();

    connectableFlowable.subscribe(test -> Timber.d(test.toString()));

    return new AlertDialog.Builder(context)
            .setTitle("Add new Project")
            .setView(dialogView)
            .setPositiveButton(android.R.string.ok, (dialogInterface, i) -> {
                Timber.d("Ok clicked!");
                createProjectClicked.onNext("It works!");
            })
            .setNegativeButton(android.R.string.cancel, (dialogInterface, i) -> Timber.d("Cancel clicked!"))
            .create();
}

我只是在同一个地方发布和订阅,以确保它在将ConnectableFlowable移动到ViewModel之前实际工作。我得到的唯一日志是“点击Ok!”对我来说,这意味着它从未被订阅过。知道为什么没有订阅吗?

2 回复 | 直到 7 年前

Leandro Borges Ferreira 6 年前

我可以使用平面图实现这种行为。下面是一个示例,说明如何在文本有效的情况下显示祝酒词:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val btnSubject = PublishSubject.create<Boolean>()
    val textObservable = RxTextView.textChangeEvents(editText)
            .filter { validateText(it.text().toString()) }

    btnSubject.flatMap { textObservable }
            .subscribe({
                Toast.makeText(this, "Text is correct", Toast.LENGTH_SHORT).show()
            })


    btn.setOnClickListener {
        btnSubject.onNext(true)
    }
}

private fun validateText(text: String) = text.length >= 5

如果需要在文本不正确时显示一些反馈,可以更改地图的过滤器并按如下方式使用:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val btnSubject = PublishSubject.create<Boolean>()
    val textObservable = RxTextView.textChangeEvents(editText)
            .map { validateText(it.text().toString()) }

    btnSubject.flatMap { textObservable }
            .subscribe({ isTextCorrect ->
                if (isTextCorrect) {
                    Toast.makeText(this, "Text is correct", Toast.LENGTH_SHORT).show()
                } else {
                    Toast.makeText(this, "Text NOT is correct", Toast.LENGTH_SHORT).show()
                }
            })


    btn.setOnClickListener {
        btnSubject.onNext(true)
    }
}

private fun validateText(text: String) = text.length >= 5

我刚刚测试了这段代码,效果很好。

快乐的代码!

davisjp 6 年前

Java版本:

private Observable<TextViewTextChangeEvent> taskTitleObservable;
private final PublishSubject<Boolean> createTaskClicked = PublishSubject.create();

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    ButterKnife.bind(this, view);

    taskTitleObservable = RxTextView.textChangeEvents(taskTitle)
    .filter(event -> validateText(event.text().toString()));

    createTaskClicked.flatMap(test -> taskTitleObservable).subscribe( aVoid -> {
        Toast.makeText(getActivity(), "Text is correct", Toast.LENGTH_SHORT).show();
    });

    RxView.clicks(fab).subscribe(aVoid -> {
        createTaskClicked.onNext(true);
    });
}

private Boolean validateText (String text) {
    return text.length() >= 5;
}

如果文本不正确,则反馈:

private Observable<Boolean> taskTitleObservable;
private final PublishSubject<Boolean> createTaskClicked = PublishSubject.create();

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    ButterKnife.bind(this, view);

    taskTitleObservable = RxTextView.textChangeEvents(taskTitle)
            .map(event -> validateText(event.text().toString()));

    createTaskClicked.flatMap(test -> taskTitleObservable).subscribe( isTextCorrect -> {
        if (isTextCorrect) {
            Toast.makeText(getActivity(), "Text is correct", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(getActivity(), "Text is incorrect", Toast.LENGTH_SHORT).show();
        }
    });

    RxView.clicks(fab).subscribe(aVoid -> {
        createTaskClicked.onNext(true);
    });
}

private Boolean validateText (String text) {
    return text.length() >= 5;
}