android - 如何在 fragment 中实现OnClick和OnFocusChanged监听器

Question

我有一个MainActivity和ViewPager2和FragmentStateAdapter。在这个ViewPager中，我有5种不同布局的Fragments。我正在尝试在所说的EditTexts上实现一些Buttons和Fragments。但是，没有任何侦听器触发器。
调试时，将执行onCreate中的所有代码，但永远不会触发监听器。

这是我的片段:

class SearchFragment : Fragment() {


private lateinit var searchBinding: FragmentSearchBinding

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    searchBinding = FragmentSearchBinding.inflate(layoutInflater)



    var test = activity?.findViewById<TabLayout>(R.id.tab_layout)

    searchBinding.testButton.setOnClickListener{
        v -> Toast.makeText(context,"This is a test",Toast.LENGTH_SHORT).show()
    }

    searchBinding.searchBar.setOnFocusChangeListener{view, hasFocus ->
        if (hasFocus){
            if (test != null) {
                test.isVisible = false
            }
            Log.d("SearchFragment", "onFocus")
        }else{
            if (test != null) {
                test.isVisible = true
            }
        }

    }

}

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_search, container, false)


}

override fun onClick(v: View) {
    when (v.id) {
        R.id.search_bar -> {
            Toast.makeText(v.context, "This is a test", Toast.LENGTH_SHORT)
        }
    }
}

}

这是我的ViewPager适配器:

private const val NUM_PAGES = 5


class ViewPagerFragmentAdapter(fragmentActivity: FragmentActivity) : FragmentStateAdapter (
    fragmentActivity
)
{



override fun getItemCount(): Int {
    return NUM_PAGES
}

override fun createFragment(position: Int): Fragment {
    when (position) {
        0 -> return RankingFragment()
        1 -> return RateFragment()
        2 -> return ProfileFragment()
        3 -> return SearchFragment()
        4 -> return ChatFragment()
    }
    return ProfileFragment()
}

}

Answer 1

我认为您需要阅读有关片段的生命周期的信息。处理View的生命周期部分介于onCreateView和onDestroyView之间。 onCreate在此之前发生。 Check out the guide from Android。

另外，我对ViewBinding的经验也不多，但是我认为您做的不正确。

根据documentation，您应该按照以下方式进行操作:

class SearchFragment : Fragment() {


  private var _binding: FragmentSearchBinding? = null
  // This property is only valid between onCreateView and
  // onDestroyView.
  private val searchBinding get() = _binding!!

  override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
  ): View? {
    _binding = FragmentSearchBinding.inflate(inflater, container, false)
    val view = searchBinding.root

    var test = activity?.findViewById<TabLayout>(R.id.tab_layout)

    searchBinding.testButton.setOnClickListener{
        v -> Toast.makeText(context,"This is a test",Toast.LENGTH_SHORT).show()
    }

    searchBinding.searchBar.setOnFocusChangeListener{view, hasFocus ->
        if (hasFocus){
            if (test != null) {
                test.isVisible = false
            }
            Log.d("SearchFragment", "onFocus")
        }else{
            if (test != null) {
                test.isVisible = true
            }
        }

    }

    return view
  }

  override fun onDestroyView() {
    _binding = null
  }

}