小编Abd*_*bri的帖子

据我所知,RxJava2 values.take(1)创建了另一个Observable,它只包含原始Observable中的一个元素.哪个不能抛出异常,因为它被take(1)第二次发生的效果过滤掉了.

如下面的代码片段所示

    Observable<Integer> values = Observable.create(o -> {
        o.onNext(1);
        o.onError(new Exception("Oops"));
    });

    values.take(1)
            .subscribe(
                    System.out::println,
                    e -> System.out.println("Error: " + e.getMessage()),
                    () -> System.out.println("Completed")
            );

产量

1
Completed
io.reactivex.exceptions.UndeliverableException: java.lang.Exception: Oops
    at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:366)
    at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onError(ObservableCreate.java:83)
    at ch02.lambda$main$0(ch02.java:28)
    at io.reactivex.internal.operators.observable.ObservableCreate.subscribeActual(ObservableCreate.java:40)
    at io.reactivex.Observable.subscribe(Observable.java:10841)
    at io.reactivex.internal.operators.observable.ObservableTake.subscribeActual(ObservableTake.java:30)
    at io.reactivex.Observable.subscribe(Observable.java:10841)
    at io.reactivex.Observable.subscribe(Observable.java:10827)
    at io.reactivex.Observable.subscribe(Observable.java:10787)
    at ch02.main(ch02.java:32)
Caused by: java.lang.Exception: Oops
    ... 8 more
Exception in thread "main" io.reactivex.exceptions.UndeliverableException: java.lang.Exception: Oops
    at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:366)
    at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onError(ObservableCreate.java:83)
    at ch02.lambda$main$0(ch02.java:28)
    at …

设想

当我点击ctrl+class name打开一个类的源代码时，android studio 通常会打开一个带有存根方法的虚拟实现。当我降低compileSdkVersion到29这些动作正常工作时。

问题

我Sources for Android 30在sdkmanager窗口找不到。

题

它会很快发布还是我错过了什么？

您好，我不知道如何在 jetpack compose 中制作切角菜单1.0.0-beta02。我尝试用表面包裹 while 菜单，但没有用。

    TopAppBar(
        modifier = Modifier
            .statusBarsPadding(),
        title = {
            Text(text = "Title")
        },
        actions = {
            var menuExpanded by remember { mutableStateOf(false) }

            IconButton(onClick = { menuExpanded = true }) {
                Icon(Icons.Default.MoreVert, contentDescription = null)
            }

            DropdownMenu(
                expanded = menuExpanded,
                onDismissRequest = {
                    menuExpanded = false
                },
            ) {
                DropdownMenuItem(onClick = {}) {
                    Text("Item 2")
                }
            }
        },
    )

这给了我

但我需要这样的东西，它是四舍五入的。