我有一个启动另一个活动的活动。 这是必须通过我指定的Andr​​oid清单父活动？ 我要问这个，因为可能还有其他的活动，将启动该之一，也是，所以我应该指定其中的呢？

 安卓parentActivityName =com.example.myfirstapp.MainActivity
 

解决方案

您只需指定，如果你打算使用最多导航（如按后退按钮而不是导航）。在其他情况下，你不需要它。

请在这里约了导航：http://developer.android.com/design/patterns/navigation.html

I have an activity that starts another activity. Is it mandatory that I specify the parent activity in the Android Manifest? Im asking this because there might be other activities that will start this one as well, so should I specify all of them?

    android:parentActivityName="com.example.myfirstapp.MainActivity" 

You only need to specify that if you're going to use up-navigation (as opposed to navigation by back button). In other cases, you don't need it.

Check in here about up-navigation: http://developer.android.com/design/patterns/navigation.html