简体繁体 English

android第一次在ViewModel中初始化LiveData怎么办？使用哪个工厂？

[英]How to initialize the LiveData in ViewModel for the first time in android? and which factory to use?

原文 2020-07-29 09:48:55 2 1 android/ viewmodel

I want to initialize the LiveData value when the app is launched, not every time the orientation changes.我想在应用程序启动时初始化 LiveData 值，而不是每次方向改变时。 Can I use the constructor of the subclass of ViewModel for it?我可以使用 ViewModel 的子类的构造函数吗？

1 个解决方案

Instead of LiveData which pushes the last value to observers for every config change (like a RxJava BehaviourSubject ), you should use something which pushes the event once.而不是LiveData将最后一个值推送给每个配置更改的观察者（如 RxJava BehaviourSubject ），您应该使用将事件推送一次的东西。

You can use:您可以使用：

SingleLiveEvent : Send the event to only 1 observer, check here and here or alternatives here SingleLiveEvent ：仅将事件发送给 1 个观察者，检查此处和此处或此处的替代方案
LiveEvent : Send the event to all the observers, check here LiveEvent : 发送事件给所有观察者，勾选这里

Both of those approaches will not cache events, which means that an observer should be already observing the *LiveEvent to receive it这两种方法都不会缓存事件，这意味着观察者应该已经在观察*LiveEvent以接收它

You can find articles online about alternative approaches but the philosophy behind them is probably the same您可以在网上找到有关替代方法的文章，但它们背后的理念可能是相同的

稍后在 ViewModel 中初始化 LiveData - Initialize LiveData later in ViewModel

一段时间后如何使 ViewModel/LiveData 无效？ - How to invalidate ViewModel/LiveData after some time?

如何在 ViewModel 中为数据类参数 LiveData 设置初始化和设置值 - How to set initialize and set value to data class parameter LiveData in ViewModel

如何将WearableActivity与LiveData和ViewModel结合使用 - How can I use WearableActivity with LiveData and ViewModel

如何在多个Activity中使用ViewModel和LiveData观察器？ - How use a ViewModel & LiveData observer in multiple Activity?

如何将 livedata 和 viewmodel 与 Viewholder 作为生命周期所有者一起使用？ - How to use livedata and viewmodel with a viewholder as Lifecycle Owner?

如何在 Room 中将 SearchView 与 LiveData 和 ViewModel 一起使用 - How to use SearchView with LiveData and ViewModel in Room

android中的ViewModel LiveData不起作用 - ViewModel LiveData in android not working

Android ViewModel LiveData 观察 - Android ViewModel LiveData observe

Android ViewModel LiveData 文档 - Android ViewModel LiveData Documentation

暂无

暂无

声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.

相关问题 稍后在 ViewModel 中初始化 LiveData - Initialize LiveData later in ViewModel 一段时间后如何使 ViewModel/LiveData 无效？ - How to invalidate ViewModel/LiveData after some time? 如何在 ViewModel 中为数据类参数 LiveData 设置初始化和设置值 - How to set initialize and set value to data class parameter LiveData in ViewModel 如何将WearableActivity与LiveData和ViewModel结合使用 - How can I use WearableActivity with LiveData and ViewModel 如何在多个Activity中使用ViewModel和LiveData观察器？ - How use a ViewModel & LiveData observer in multiple Activity? 如何将 livedata 和 viewmodel 与 Viewholder 作为生命周期所有者一起使用？ - How to use livedata and viewmodel with a viewholder as Lifecycle Owner? 如何在 Room 中将 SearchView 与 LiveData 和 ViewModel 一起使用 - How to use SearchView with LiveData and ViewModel in Room android中的ViewModel LiveData不起作用 - ViewModel LiveData in android not working Android ViewModel LiveData 观察 - Android ViewModel LiveData observe Android ViewModel LiveData 文档 - Android ViewModel LiveData Documentation

相关标签

粤ICP备18138465号 © 2020-2024 STACKOOM.COM