in androidx.fragment.app.Fragment，setUserVisibleHint（）is Deprecated，and not executed,why？

Solution 1:

They just changed API in Fragments.

If you use this method to limit fragments lifecycle:

You can now set a max Lifecycle state for a Fragment by calling setMaxLifecycle() on a FragmentTransaction. This replaces the now deprecated setUserVisibleHint().

Source: https://developer.android.com/jetpack/androidx/releases/fragment#1.1.0-alpha07 .

If you need this method because you try to detect which fragment is currently visible in ViewPager. You can now just use onResume and onPause methods instead but before that you should change default behaviour in FragmentPagerAdapter constructor.

Like this:

FragmentPagerAdapter(fragmentManager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT)

Edit: Because FragmentPagerAdapter is deprecated as well it is better to use ViewPager2 now. In case of ViewPager2 it is default behaviour and we can use onResume and onPause methods to know which fragment is currently visible.

Solution 2:

Now in AndroidX method setUserVisibleHint(boolean isVisibleToUser) is deprecated and if you take a look into documentation, it says:

You can now set a max Lifecycle state for a Fragment by calling setMaxLifecycle() on a FragmentTransaction. This replaces the now deprecated setUserVisibleHint(). FragmentPagerAdapter and FragmentStatePagerAdapter have a new constructor that allows you to switch to the new behavior.

So basically when you use this approach in FragmentTransaction:

.getSupportFragmentManager()
            .beginTransaction()
            .setMaxLifecycle(fragment, Lifecycle.State.STARTED);

would be equivalent to setUserVisibleHint(false) and:

.getSupportFragmentManager()
            .beginTransaction()
            .setMaxLifecycle(fragment, Lifecycle.State.RESUMED);

would be equivalent to: setUserVisibleHint(true)