Android：何时设置工具栏标题表单片段？(Android: when to set Toolbar title form Fragment?)

Android：何时设置工具栏标题表单片段？(Android: when to set Toolbar title form Fragment?)

我有一个包含一些片段的ViewPager。

我需要在片段更改时更新活动工具栏上的标题。

我应该在Fragment的哪个生命周期方法中调用Activity来设置新标题？

使用setUserVisibleHint(true)会很好，但有时当Activity实际上没有准备好时它会被调用（Toolbar为null）。

此外，我需要管理配置更改，并需要确保工具栏中的标题是当前显示的片段之一。

谢谢

I have a ViewPager that contains some Fragments.

I need to update the title on the Activity Toolbar when the fragment changes.

In which lifecycle method of the Fragment should I call the Activity to set the new title?

It would be nice to use setUserVisibleHint(true), but sometimes it gets called when the Activity is not actually ready (Toolbar is null).

And additionally I need to manage the config change and need to makes sure that the title in the Toolbar is the one of the Fragment currently displayed.

Thanks

最满意答案

我认为更好的选择是在onPageSelected()做到这onPageSelected()

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { } @Override public void onPageScrollStateChanged(int state) { } });

I think the better option is do that in onPageSelected()

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { } @Override public void onPageScrollStateChanged(int state) { } });