Develop Reference

Fragment incide AppCompatDialog

I have simple DialogWindow
XML:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="300dp"
android:layout_height="150dp"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<fragment
android:id="#+id/nav_host_fragment_activity_main"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="#navigation/navigation"/>
</LinearLayout>
Code:
class DialogWindowBuyingStock(context: Context, private val viewModel: MainViewModel, private val stock: Stock) : AppCompatDialog(context) {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
supportRequestWindowFeature(Window.FEATURE_NO_TITLE)
setContentView(R.layout.buy_stock_dialogwindow)
}
}
In which i have some fragments for example the Main one:
class MainFragment : Fragment() {
private var _binding: MainFragmentBinding? = null
private val binding get() = _binding!!
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
val homeViewModel =
ViewModelProvider(this)[MainFragmentViewModel::class.java]
_binding = MainFragmentBinding.inflate(inflater, container, false)
val root: View = binding.root
return root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
main_buy_button.setOnClickListener {
Navigation.findNavController(view).navigate(R.id.action_mainFragment_to_buyFragment)
}
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
}
It works perfectly for the first time i start Dialog Window, but when i close it and start again, i got this llegalArgumentException: Binary XML file line #20: Duplicate id 0x7f080136, tag null, or parent id 0xffffffff with another fragment for androidx.navigation.fragment.NavHostFragment
How can i fix that?

Android Buttons in Fragments to not get triggered

Why do buttons in Fragments to not get triggered? I've already spent about 5 hours on this, but no onClick / onFocusListener will trigger
Edit: Code
So this Fragment(s) is on a ViewPager2 on my MainActivity and
it just wont trigger any Callback Methods. I have also tried to but those onClick initializations everywhere
Fragment:
class SearchFragment : Fragment() {
private lateinit var searchBinding: FragmentSearchBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
searchBinding = FragmentSearchBinding.inflate(layoutInflater)
interface OnSearch {
fun onArticleSelected(position: Int)
}
}
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 onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
var test = activity?.findViewById<TabLayout>(R.id.tab_layout)
searchBinding.searchBar.setOnFocusChangeListener{view, hasFocus ->
if (hasFocus){
if (test != null) {
test.isVisible = false
}
Log.d("SearchFragment", "onFocus")
}else{
if (test != null) {
test.isVisible = true
}
}
}
}
}
XML:
<?xml version="1.0" encoding="utf-8"?>
<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=".ui.main.search.SearchFragment"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.google.android.material.button.MaterialButton
android:id="#+id/testButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<EditText
android:id="#+id/search_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="20sp"
android:hint="Search"
android:focusedByDefault="true"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/searchRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
</FrameLayout>

Try something like this
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) {
super.onCreateView(view, savedInstanceState)
val binding = FragmentSearchBinding.inflate(inflater, container, false);
val view = binding.root
// Set binding
return view;
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
view.findViewById(R.id.searchBar).setOnFocusChangeListener { view, hasFocus ->
}
}

On click of the Button I want Fragment 1 layout to be replaced with Fragment 2 layout but its throwing: java.lang.NullPointerException

First Fragment's code
class MainFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val mainInflater = inflater.inflate(R.layout.fragment_main, container, false)
return mainInflater
}
fun thisdata():String{
return "Hello from MainFragment"
}
}
First Fragment XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".MainFragment">
<EditText
android:id="#+id/etSavedData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="60dp"
android:hint="Enter the Text"/>
<Button
android:id="#+id/btnSaveData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="120dp"
android:text="Save"/>
</RelativeLayout>
Main Activity's code
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
//Set replace Main Activity content with the Fragment1 content
val mainFragment = MainFragment()
supportFragmentManager.beginTransaction().add(R.id.contain_fragment, mainFragment).commit()
val thedata = mainFragment.thisdata()
Log.e("Main Frag to Activity", thedata)
btnSaveData.setOnClickListener {
val secondFragment = SecondFragment()
supportFragmentManager.beginTransaction().add(R.id.contain_fragment, secondFragment).commit()
}
}
}
Main Activity XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/contain_fragment"
tools:context=".MainActivity">
</RelativeLayout>
Second Fragment's code
class SecondFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val secondInflater = inflater.inflate(R.layout.fragment_second, container, false)
return secondInflater
}
}
Second Fragment XML
<?xml version="1.0" encoding="utf-8"?>
<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"
android:background="#android:color/holo_blue_dark"
tools:context=".SecondFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:id="#+id/tvDisplayText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:text="Text displayed here." />
</FrameLayout>
Following Exception showing up in Logcat
Caused by: java.lang.NullPointerException: Attempt to invoke virtual
method 'void
android.widget.Button.setOnClickListener(android.view.View$OnClickListener)'
on a null object reference
at com.example.demo2.MainActivity.onCreate(MainActivity.kt:22)*

You either need to move your btnSaveData button into the MainActivity, or you should move the onClickListener into the MainFragment, along with some other changes. Something like:
class MainFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val mainInflater = inflater.inflate(R.layout.fragment_main, container, false)
btnSaveData.setOnClickListener {
val secondFragment = SecondFragment()
activity.supportFragmentManager.beginTransaction().add(R.id.contain_fragment, secondFragment).commit()
}
return mainInflater
}
fun thisdata():String{
return "Hello from MainFragment"
}
}

**Thanks Tash, that actually make sense, unfortunately it was still showing the same exception but I finally manage to resolve the issue by doing the following. **
class MainFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val mainInflater = inflater.inflate(R.layout.fragment_main, container, false)
mainInflater.btnSaveData.setOnClickListener {
val secondFragment = SecondFragment()
secondFragment?.let {
activity?.supportFragmentManager?.beginTransaction()?.replace(R.id.contain_fragment, secondFragment)?.commit()
}
}
return mainInflater
}
fun thisdata():String{
return "Hello from MainFragment"
}
}

Tablayout doesn't work in Fragment in Android kotlin

I'm trying to add tablayout in one of my fragments.
tablayout in mainActivity works well, but tablayout in fragment doesn't work.
Tab menu shows well, but nothing comes up in my viewPager.
I want to make like this.
and it's my app
HomeDetailFragment.kt
class HomeDetailFragment : Fragment() {
lateinit var homeDetailRecyclerViewAdapter : HomeDetailRecyclerViewAdapter
private val myContext = FragmentActivity()
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_home_detail, container, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
configureTopNavigation()
}
private fun configureTopNavigation(){
vp_home_detail.adapter = HomeDetailPagerAdapter(myContext.supportFragmentManager, 5)
vp_home_detail.offscreenPageLimit = 5
tl_home_detail_bar.setupWithViewPager(vp_home_detail)
}
}
HomeDetailPagerAdapter.kt
class HomeDetailPagerAdapter (fm : FragmentManager, val fragmentCount : Int): FragmentStatePagerAdapter(fm){
private val fragmentTitleList = mutableListOf("전체", "요가","발레", "태권도", "헬스")
override fun getItem(position:Int): Fragment{
when(position){
0-> return HomeFragment()
1-> return WholeFragment()
2-> return YogaFragment()
3-> return BalletFragment()
4-> return TakFragment()
else -> return HomeFragment()
}
}
override fun getPageTitle(position: Int):CharSequence?{
return fragmentTitleList[position]
}
override fun getCount(): Int = fragmentCount
}
fragment_home_detail.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#f2f7ff"
tools:context=".ui.home.HomeDetailFragment">
<com.google.android.material.tabs.TabLayout
android:id="#+id/tl_home_detail_bar"
android:layout_width="match_parent"
android:layout_height="48dp"
android:background="#ffffff"
app:tabIndicatorColor="#2c77f1"
android:layout_alignParentTop="true"
android:theme="#style/HomeDetailTab"
android:elevation="5dp" />
<androidx.viewpager.widget.ViewPager
android:id="#+id/vp_home_detail"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/tl_home_detail_bar"/>

Use childFragmentManager instead of myContext.supportFragmentManager
vp_home_detail.adapter = HomeDetailPagerAdapter(childFragmentManager, 5)

ViewPager is not working correctly after device rotation

After rotation, one old page is displayed, followed by new pages.
Before rotation 1.
After rotation 2.
Layout with ViewPager:
<RelativeLayout ...
<androidx.viewpager.widget.ViewPager
android:id="#+id/pager"
android:overScrollMode="never"
android:layout_marginStart="16dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="10dp"
android:layout_height="match_parent"
android:layout_width="match_parent">
</RelativeLayout>
Fragment with this layout:
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
val view = inflater.inflate(layoutId(), container, false)
view.findViewById<ViewPager>(R.id.pager).adapter = TextPagerAdapter(activity!!.supportFragmentManager, listOf())
return view
}
TextPagerAdapter:
override fun getItem(position: Int): Fragment = PageFragment.newInstance("sssssss ssss $position")
override fun getCount() = 5//pageText.size
}
PageFragment:
override fun onCreateView(inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?): View? {
val view = inflater.inflate(layoutId(), container, false)
view.findViewById<TextView>(R.id.page_content_textView).text = arguments!!.getCharSequence(PAGE_TEXT)
return view
}

I forgot to check if the content fragment is already created.
The solution is to check if the savedInstanceState == null. And create new fragment if that condition is true.
In MyActivity:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
if(savedInstanceState == null) this.supportFragmentManager.beginTransaction()
.add(containerViewId, CollectionDemoFragment()).commit()
}