Android SavedStateHandle 不保存在 ViewModel 中

问题描述

我有一个带有 SavedStateHandle 参数的 ViewModel.我正在像这样保存一个字符串:

 私人乐趣 saveString(str: String) {state.set(KEY_STRING, str)}

然后我强制关闭我的应用程序并重新启动它，并想像这样检索保存的字符串:

有趣的 getSavedString():字符串?{返回 state.get(KEY_String)}

然而，它总是返回 null.任何想法如何正确使用 SavedStateHandle?

解决方案

然后我强制关闭我的应用并重新启动它.."

我猜你完全杀死了应用 =)

重现saveState案例的方法之一:

1. 启用开发者模式并检查不要保留活动
2. 进程限制 ->无后台进程
3. 在后台向您发送应用程序(SavedStateHandle 将保存)
4. 从后台恢复应用程序或点击应用程序图标(SavedStateHandle 将恢复)

另一种最简单的方法:

1. 在后台向您发送应用
2. 点击终止 (Logcat)

1. 从后台恢复应用或点击应用图标

如果你想，你也应该使用 SavedStateViewModelFactory在 ViewModel

中接收 SavedStateHandle

I have a ViewModel which takes a SavedStateHandle parameter. I am saving a String in there like this:

    private fun saveString(str: String) {
        state.set(KEY_STRING, str)
    }

Then I force-close my app and relaunch it, and want to retrieve the saved string like this:

fun getSavedString(): String? {
        return state.get<String>(KEY_String)
    }

However, it always returns null. Any ideas how to use SavedStateHandle correctly?

解决方案

"Then I force-close my app and relaunch it.."

I guess you kill the app completely =)

One of the way for reproducing saveState case you need:

1. Enable developers mode and check Don't keep activities
2. Process limit -> No background processes
3. Send you app in background (SavedStateHandle will saved)
4. Restore app from background or tap on the icon of app (SavedStateHandle will restored)

Another the easiest way:

1. Send you app in background
2. Tap terminate (Logcat)

1. Restore app from background or tap on the icon of app

这篇关于Android SavedStateHandle 不保存在 ViewModel 中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！