在片段中隐藏或显示操作栏 Kotlin

Question

I have to know the best way to deal with hiding or show Action Bar in Fragments. I figured out that it, not the same as in Activity where I could apply the style in Manifest. I have tried to apply the style in the Fragment XML file with no effect.

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".PreviewFragment"
    **style="@style/MyStyleHereNoActionBar"**>
</FrameLayout>

Another option that worked, but might be unstable is:

class PreviewFragment : Fragment() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        arguments?.let {

        }
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment

// hide action bar         (requireActivity() as AppCompatActivity).supportActionBar?.hide()
// show action bar         (requireActivity() as AppCompatActivity).supportActionBar?.show()

        return inflater.inflate(R.layout.fragment_preview, container, false)
    }

and the last one adding one or both methods:

override fun onResume() {
        super.onResume()
        (activity as AppCompatActivity?)!!.supportActionBar!!.hide()
    }

    override fun onStop() {
        super.onStop()
        (activity as AppCompatActivity?)!!.supportActionBar!!.show()
    }

So I love to know what I could do better or another way of doing it. Or rather a right way to do it.

And second how to apply custom styles to Fragments the right way.

Thank you.

Answer 1

You are adding fragments inside an activity and the activity has action bar. So in the specific fragment where you want to show the action bar get the activity and show the activity, and hide it where you don't want to show.

Or if you want to use action bar inside a fragment then just add a linear layout to the top of the fragment with height "?android:attr/actionBarSize" . I think this should do the job.