我展示一些碎片的活动。 活动视图只包含ViewPager定制FragmentPagerAdapter初始化。 该适配器提供中3个片段导航。

I have an activity showing a few fragments. Activity view contains only ViewPager initialized with custom FragmentPagerAdapter. This adapter provide navigation among 3 fragments.

一切似乎做工精细，除了行动吧。

All seems to work fine except Action bar.

我重写onCreateOptionsMenu（）方法，在我的片段创造任何片段单独行动起来吧：

I override onCreateOptionsMenu() method in my fragments to create individual Action bar for any fragment:

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
    {
        super.onCreateOptionsMenu(menu, inflater);
        menu.clear();

当我做轻扫，新片段出现，但操作栏保持不变，几秒钟。大概几秒钟后，该方法被调用，操作栏得到改变。

When I do swipe, new fragment appears, but Action bar stay the same for a few seconds. Probably after a few seconds this method are called and Action bar get changed.

这看起来pretty的不好的时候行动起来吧刷卡完成后，在一段时间内改变。 我怎么能马上重新行动起来吧，前刷一下么？

This looks pretty bad when action bar are changed in a while after swipe is finished. How can I recreate action bar immediately, before swipe begin?

推荐答案

您可以要求机器人来重新创建动作条才通过调用自动执行 invalidateOptionsMenu（）;

You can ask android to re-create the actionbar before it automatically does by calling invalidateOptionsMenu();

做到这一点的地方接近的地方，你改变片段，试图降低片段之间以及动作条改变'滞后'的地步。

Do this somewhere close to the point where you change fragments to try and decrease the 'lag' between the fragment and actionbar changing.

修改

一个完整的解决方案可能是这样的：

a complete solution may look like this:

class activity extends Activity{

private void switchFragment(){

...do fragment changing stuff

activity.invalidateOptionsMenu();

}

}

class someFragment extends Fragment{

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
{
    super.onCreateOptionsMenu(menu, inflater);
    menu.clear();


    //fragment specific menu creation
}

}

取片段是在开放的

whichever fragment is open during the

activity.invalidateOptionsMenu();

将调用其

 onCreateOptionsMenu

，你可以做片段特定的菜单创作在里面

and you can do fragment specific menu creation in there