I need a help.

requireActivity().supportFragmentManager.beginTransaction() 　　　　.replace(R.id.nav_host_fragment, testFragment) 　　　　.addToBackStack(testFragment.tag) 　　　　.commit()

TestFragment.kt →worked

TestAdapter.kt →didn't work →requireActivity() seems to be unavailable.

What is the difference? And what should I do to display TestFragment in TestAdapter.kt? There is a button for click in TestAdapter.kt. That's why I need to do this.

CodePudding user response：

An Adapter is not a Fragment, so it doesn't have the same functions available that Fragment does. If you need an Activity reference inside an Adapter (which you shouldn't because that is poor design--poor encapsulation), you need to add a constructor parameter or property to your class that allows you to pass an Activity reference to your Adapter. For example:

class ExpandableListAdapter(val activity: Activity): ListAdapter { //...

and then when you create it in your Fragment, you could pass requireActivity() as a constructor parameter.

But like I said, this would be poor encapsulation. Maybe you just need a Context reference for when you're creating view holders? In that case, you can get it from the parent parameter:

override fun createViewHolder(parent: ViewGroup, viewType: Int) {
    val context = parent.context
    // use context to create view holder's layout
}