FragmentStatePagerAdapter 从 API 27 开始已弃用

FragmentStatePagerAdapter从 API 27 开始已弃用。替代方案是什么FragmentStatePagerAdapter?

private class MainPagerAdapter extends FragmentStatePagerAdapter {

    MainPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        Fragment result = new DummyFragment();
        return result;
    }

    @Override
    public int getCount() {
        return 5;
    }

}

上面的代码显示FragmentStatePagerAdapter, getItem(...) and super(...)已弃用。

切换到ViewPager2 https://developer.android.com/reference/androidx/viewpager2/widget/ViewPager2并使用片段状态适配器 https://developer.android.com/reference/androidx/viewpager2/adapter/FragmentStateAdapter反而。

从那里您可以使用 onPause 和 onResume 回调来确定哪个片段当前对用户可见。当片段变得可见时调用 onResume，当片段不再可见时调用 onPause。 ->阅读更多 https://stackoverflow.com/questions/10024739/how-to-determine-when-fragment-becomes-visible-in-viewpager/57888432#57888432

根据评论Eric https://stackoverflow.com/users/4233804/erik-jhordan-rey and Reejesh https://stackoverflow.com/users/14784590/reejesh.

旧答案（现在也已弃用）

以下构造函数执行相同的操作

super(@NonNull FragmentManager fm)
super(@NonNull FragmentManager fm, BEHAVIOR_SET_USER_VISIBLE_HINT)

Passing BEHAVIOR_SET_USER_VISIBLE_HINT已被弃用。你应该通过BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT反而。

通过这些的差异在中解释FragmentPagerAdapter:

 /**
 * Indicates that Fragment#setUserVisibleHint(boolean) will be 
 * called when the current fragment changes.
 */
@Deprecated
public static final int BEHAVIOR_SET_USER_VISIBLE_HINT = 0;

/**
 * Indicates that only the current fragment will be 
 * in the Lifecycle.State#RESUMED state. All other Fragments 
 * are capped at Lifecycle.State#STARTED.
 */
public static final int BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT = 1;