问题描述
我试图使用 requestWindowFeature（）函数来设置一个列表活动自定义标题视图。该方法正常工作与一种观点认为，只有子类活动，但每当我试图用 ListActivity 子类相同的方法，它的错误，给我一个NullPointerException异常，当我尝试以编程方式修改标题视图。
I'm trying to use the requestWindowFeature() function to set a custom title view on a list activity. The method works fine with a view that only subclasses Activity, but whenever I try the same method with a ListActivity subclass, it errors, giving me a NullPointerException when I try to programmatically modify the title view.
我认为这个问题涉及到 requestWindowFeature（）之前需要的setContentView被称为事实（）。因为 ListActivity 负责设置内容视图为你，我不知道被调用时。有没有人有什么建议？感谢您的帮助。
I believe the problem pertains to the fact that requestWindowFeature() needs to be called before setContentView(). Because ListActivity takes care of setting the content view for you, I don't know when that is being called. Does anyone have any suggestions? Thanks for the help.
推荐答案
当你与List交互，例如调用的GetList（）或listactivity setAdapter（）的setContentView被调用。请参阅<一个href=\"http://www.grep$c$c.com/file/repository.grep$c$c.com/java/ext/com.google.android/android/2.3.4_r1/android/app/ListActivity.java#ListActivity\"相对=nofollow> listactivity源
setContentView is called whenever you interact with the List, for example calling getList() or setAdapter() on listactivity. See the source of listactivity
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