检查返回键为pressed android系统中？ [英] Check if back key was pressed in android?

问题描述

说我对我的主要活动，我开始一个新的活动

Say I'm on my main activity and I start a new activity

MainActivity > NewActivity

和从 NewActivity I preSS返回键

And from NewActivity I press the back key

MainActivity < NewActivity

我想 MainActivity 做一些事情，如果它被显示在 NewActivity 是封闭的，而不是在 MainActivity 的正常运行，首先运行应用程序时如。有谁知道这是可能的吗？

I want MainActivity to do something if it's being displayed after NewActivity is closed, but not when MainActivity is run normally, such as when first running the application. Does anyone know if this is possible?

推荐答案

一对夫妇的想法：

• 您可以只设置一个标志 MainActivity 时，它会调用 NewActivity 。
• 您可以致电 startActivityForResult 从 MainActivity 和安排 NewActivity 来设置的结果，您将收到 MainActivity.onActivityResult（）在 NewActivity 结束。

• You can just set a flag in MainActivity when it fires up NewActivity.
• You can call startActivityForResult from MainActivity and arrange for NewActivity to set a result, which you will receive in MainActivity.onActivityResult() when NewActivity finishes.

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