我如何崩溃＆QUOT;儿童活动＆QUOT;？ [英] How do I collapse "child activities"?

问题描述

例子：我有一个具有以下行为3活动Android应用程式：

Example: I have an android app with 3 activities that has the following behaviors:

A (Home) -> B -> C

Activity A launches Activity B
Activity B launches Activity C

When user is on Activity B and they hit the Back button, it takes them Activity A
When user is on Activity C and they hit the Back button, it takes them Activity B

我想，当用户在活动C，如果他们打出了我的根活动按钮，它会带他们到活动A无添加活动A的新实例向后退堆栈中。

What I would like is when user is on Activity C, if they hit the "My Root Activity" button, it will take them to Activity A without adding a new instance of Activity A to the back stack.

所以我不希望有：

 1) A
 2) A-B
 3) A-B-C
 4) A-B-C-A

我想的是：

 1) A
 2) A-B
 3) A-B-C
 4) A

我怎样才能做到这一点？

How can I do this?

推荐答案

我有每个孩子的活动扩展基地的活动。在基础活性，我所限定的的onActivityResult（），这将施加面漆（）如果在堆栈设置特定的结果code的顶部的活性。所以，如果他们打的活动C中的我的根活动按钮，将递归地卷起到活动A.后退按钮保持它的功能。

I have each child activity extend a base activity. In the base activity, I defined an onActivityResult() which will impose a finish() if the activity at the top of the stack set a specific resultCode. So if they hit the "My Root Activity" button on Activity C, it will recursively roll up to Activity A. The Back button maintains it's functionality.

这是一种罕见的情况下，我会用singleTask，但在启动活动A涉及重新加载它，我不想情侣活动的C依赖。

This is a rare scenario as I would have used "singleTask" but launching Activity A involves reloading it's dependencies which I don't want to couple of Activity C.

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