如何在Fragments中实现OnClick和OnFocusChanged监听器

Question

我有一个带有ViewPager2和FragmentStateAdapter的MainActivity。在这个ViewPager中，我有5个具有不同布局的Fragments。我正在尝试在所述Fragments上实现一些EditTexts和Buttons。然而，没有一个监听器触发。当调试onCreate中的所有代码时，都会执行，但侦听器从未被触发。

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

我认为您需要了解Fragments的生命周期。生命周期中处理视图的部分位于onCreateView和onDestroyView之间。CCD_ 11在此之前发生。查看Android的指南。

此外，我对ViewBinding没有太多经验，但我认为你做得不对。

根据文件，你应该沿着以下路线做一些事情：

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
}
}