Develop Reference

move Constraint Layout programmatically

I want to move a ConstraintLayout programmatically. I looked through some solutions on stack overflow but they didn't work for me.
There are two ConstraintLayouts placed vertically. When the code goes into else if("android.permission.CAMERA" in permissionList.toString(), the above constraint layout (layoutLocation) will be invisible and the below constraint layout (layoutCamera) will come up and take its position. I mark where I should use declare it with 'want to use here'.
Code (apology to not ba able to post the whole code due to patent reason)
class SplashFragment : Fragment() {
private lateinit var mContext: MainActivity
private lateinit var binding : FragmentSplashBinding
private val viewModel : SplashViewModel by inject()
private val getPermissionUseCase : GetPermissionUseCase by inject()
override fun onAttach(context: Context) {
super.onAttach(context)
mContext = context as MainActivity
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
): View {
binding = DataBindingUtil.inflate(inflater, R.layout.fragment_splash, container, false)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.viewModel = viewModel
binding.lifecycleOwner = viewLifecycleOwner
}
private fun actionApplicationSetting(permissionList : List<String>) {
val layoutInflater = LayoutInflater.from(context)
val view = layoutInflater.inflate(R.layout.dialog_splash, null)
val alertDialog = AlertDialog.Builder(requireContext(), R.style.CustomAlertDialog).setView(view).create()
val layoutLocation : ConstraintLayout = view.findViewById(R.id.layout_box_location)
val layoutCamera : ConstraintLayout = view.findViewById(R.id.layout_box_camera)
for(permission in permissionList) {
if("android.permission.CAMERA" in permissionList.toString() && "android.permission.ACCESS_COARSE_LOCATION" in permissionList.toString()) {
layoutLocation.background = AppCompatResources.getDrawable(mContext, R.drawable.auth_level_blue)
layoutCamera.background = AppCompatResources.getDrawable(mContext, R.drawable.auth_level_blue)
}else if("android.permission.ACCESS_COARSE_LOCATION" in permissionList.toString()) {
layoutLocation.background = AppCompatResources.getDrawable(mContext, R.drawable.auth_level_blue)
}else if("android.permission.CAMERA" in permissionList.toString()) {
layoutLocation.visibility = View.INVISIBLE
// want to use here
}
}
alertDialog.show()
}
}
XML
<?xml version="1.0" encoding="utf-8"?>
<layout 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">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/layout_main"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="wrap_content"
android:layout_height="60dp"
android:layout_marginStart="70dp"
android:layout_marginBottom="10dp"
app:layout_constraintBottom_toBottomOf="#+id/layout_wrapper"
app:layout_constraintEnd_toEndOf="#+id/layout_wrapper"
app:layout_constraintStart_toStartOf="#+id/layout_wrapper">
</androidx.constraintlayout.widget.ConstraintLayout>
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/layout_wrapper"
android:layout_width="match_parent"
android:layout_height="180dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/layout_box_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/layout_box_camera"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/layout_box_location" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

Instead of layoutLocation.visibility = View.INVISIBLE try layoutLocation.visibility = View.GONE

creating bottom sheet dialog with ConstraintLayout

I am trying to create modal bottom sheet dialog to show a list of items which will be scrollable.
dialog_bottom_example.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/white"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:id="#+id/container"
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="vertical"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Items in LinearLayout is getting added dynamically based on list size as below:
ExampleDialogBottom:
class ExampleDialogBottom: BottomSheetDialogFragment() {
private lateinit var binding: DialogExampleBinding
private var skusItems = mutableListOf<SkuItem>();
companion object {
internal const val TAG = "ExampleDialogBottom"
#JvmStatic
fun newInstance(nonEligibleErxItem: NonEligibleErxItem) = NonEligibleBottomDialog
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
binding = DialogExampleBinding.inflate(inflater, container, false)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
configureSkuItems()
}
private fun configureSkuItems() {
if (!skuItems.isNullOrEmpty()) {
val inflater = LayoutInflater.from(context)
for (sku in skuItems) {
val skuItemView = SingleSkuItemViewBinding.inflate(inflater, null, false)
skuItemView.skuImage.setImageWithVisibility(sku.imageUrl)
skuItemView.skuTitle.setTextWithVisibility(sku.name)
binding.container.addView(skuItemView.root)
}
binding.container.visibility = View.VISIBLE
} else {
binding.container.visibility = View.GONE
}
}
ExmpaleActivity:
button.setOnClickListener {
ExampleDialogBottom.newInstance().show(getSupportFragmentManager(),
ExampleDialogBottom.TAG);
}
However, when I click on button, a transparent dialog shows up, no content is showing.
When I removed match-contraint and changed it match-parent or wrap-content, it's working as expected.
It would be great if someone could help? Thanks in advance.

Trouble with Recyclerview. recyclerview.xml must no be null

i have the xml with recyclerview, id = list_chat
<androidx.constraintlayout.widget.ConstraintLayout
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.chats.ChatsFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/list_chat"
android:layout_width="match_parent"
android:layout_height="match_parent">
</androidx.recyclerview.widget.RecyclerView>
</androidx.constraintlayout.widget.ConstraintLayout>
my Fragment where will be recyclerview with function uploadList which put data in my array for recyclerView
class ChatsFragment : Fragment() {
var list: MutableList<Chat> = ArrayList()
lateinit var adapter: ChatListAdapter
lateinit var manager: RecyclerView.LayoutManager
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
uploadList()
Log.e("TAG", list.toString())
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view: View = inflater.inflate(R.layout.fragment_chats, container, false)
uploadList()
manager = LinearLayoutManager(activity)
list_chat.layoutManager = manager
adapter = ChatListAdapter(list)
list_chat.adapter = adapter
return view
}
private fun uploadList(){
list.add(Chat("11111", "11111"))
list.add(Chat("11222221", "133311"))
list.add(Chat("1122221", "114444411"))
list.add(Chat("112222211", "5555555"))
}
}
xml with item for list. ImageView is no matter for now. Need only two textView
<?xml version="1.0" encoding="utf-8"?>
<layout
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout
android:id="#+id/item_list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<de.hdodenhof.circleimageview.CircleImageView
android:id="#+id/chatImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#mipmap/ic_launcher"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginStart="5sp">
<TextView
android:id="#+id/nameChat"
android:text="2222222222222"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="#+id/infoChat"
android:text="11111111"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
</LinearLayout>
</layout>
and my custom Adapter
class ChatListAdapter(private val myDataset: MutableList<Chat>) :RecyclerView.Adapter<ChatListAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
.inflate(R.layout.item_list, parent, false)
return ViewHolder(layoutInflater)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.bind(myDataset[position])
}
override fun getItemCount() = myDataset.size
class ViewHolder(v: View) : RecyclerView.ViewHolder(v){
private val nameChat: TextView = itemView.findViewById(R.id.nameChat)
private val infoChat: TextView = itemView.findViewById(R.id.infoChat)
fun bind(chat: Chat){
nameChat.text = chat.name
infoChat.text = chat.info
}
}
}
and i catch java.lang.IllegalStateException: list_chat must not be null here list_chat.layoutManager = manager
help me with it, i have list_chat only in fragment_chats, so it is right recyclerview.
Because help me pls, I dont know what is the problem

Initialize layout manager and adapter in onViewCreated() Method
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
uploadList()
manager = LinearLayoutManager(activity)
list_chat.layoutManager = manager
adapter = ChatListAdapter(list)
list_chat.adapter = adapter
})

Are you using kotlinx.android.synthetic to find your views? If so, these are not valid until after onCreateView() returns, and so you cannot use them within onCreateView().
Move your code to onViewCreated(), or switch to manually calling view.findViewById() from inside onCreateView().

Approach 1 :
Create a recyclerview object :
val rv = view.findViewById(your rv id)
and assign the layout manager and adapter to it.
Approach 2 :
In your layout file, in recyclerview add this line :
<androidx.recyclerview.widget.RecyclerView
<!-- your default lines -->
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
/>
and assign the adapter in onViewCreated method.

RecyclerView not showing in Layout

I want to achieve a layout as shown in the Android Studio preview (left). However if executed in the emulator, only the button is visible and the RecyclerView is not visible/populated (right).
The XML code:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
style="#style/AppTheme">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/list"
android:name="com.example.app.ItemFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:layoutManager="LinearLayoutManager"
tools:context=".ItemFragment"
tools:listitem="#layout/fragment_item"
android:scrollbars="vertical"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/floatingActionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:layout_margin="#dimen/fab_margin"
android:clickable="true"
android:focusable="true"
android:src="#android:drawable/ic_input_add"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
However if the RecyclerView is alone in the fragment the list is populated (but of course the action button is not showing). Code see below. And yes, my list which should be shown is not empty.
<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView 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:id="#+id/list"
android:name="com.example.app.ItemFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
app:layoutManager="LinearLayoutManager"
tools:context=".ItemFragment"
tools:listitem="#layout/fragment_item" >
</androidx.recyclerview.widget.RecyclerView>
I have already tried using RelativeLayout and FrameLayout, but I still get the same result. The same behavior occurs if I use e.g. a TextView instead of the action button.
--- Requested additional info ---
Adapter class (automatically generated by Android Studio, template):
class MyItemRecyclerViewAdapter(
private val mValues: List<DummyItem>,
private val mListener: OnListFragmentInteractionListener?
) : RecyclerView.Adapter<MyItemRecyclerViewAdapter.ViewHolder>() {
private val mOnClickListener: View.OnClickListener
init {
mOnClickListener = View.OnClickListener { v ->
val item = v.tag as DummyItem
// Notify the active callbacks interface (the activity, if the fragment is attached to
// one) that an item has been selected.
mListener?.onListFragmentInteraction(item)
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.fragment_item, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val item = mValues[position]
holder.mIdView.text = item.id
holder.mContentView.text = item.content
with(holder.mView) {
tag = item
setOnClickListener(mOnClickListener)
}
}
override fun getItemCount(): Int = mValues.size
inner class ViewHolder(val mView: View) : RecyclerView.ViewHolder(mView) {
val mIdView: TextView = mView.item_number
val mContentView: TextView = mView.content
override fun toString(): String {
return super.toString() + " '" + mContentView.text + "'"
}
}
}
List fragment (automatically generated by Android Studio, template):
class ItemFragment : Fragment() {
// TODO: Customize parameters
private var columnCount = 1
private var listener: OnListFragmentInteractionListener? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
arguments?.let {
columnCount = it.getInt(ARG_COLUMN_COUNT)
}
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_item_list, container, false)
// Set the adapter
if (view is RecyclerView) {
with(view) {
layoutManager = when {
columnCount <= 1 -> LinearLayoutManager(context)
else -> GridLayoutManager(context, columnCount)
}
adapter = MyItemRecyclerViewAdapter(DummyContent.ITEMS, listener)
}
}
return view
}
override fun onAttach(context: Context) {
super.onAttach(context)
if (context is OnListFragmentInteractionListener) {
listener = context
} else {
throw RuntimeException(context.toString() + " must implement OnListFragmentInteractionListener")
}
}
override fun onDetach() {
super.onDetach()
listener = null
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
*
*
* See the Android Training lesson
* [Communicating with Other Fragments](http://developer.android.com/training/basics/fragments/communicating.html)
* for more information.
*/
interface OnListFragmentInteractionListener {
// TODO: Update argument type and name
fun onListFragmentInteraction(item: DummyItem?)
}
companion object {
// TODO: Customize parameter argument names
const val ARG_COLUMN_COUNT = "column-count"
// TODO: Customize parameter initialization
#JvmStatic
fun newInstance(columnCount: Int) =
ItemFragment().apply {
arguments = Bundle().apply {
putInt(ARG_COLUMN_COUNT, columnCount)
}
}
}
}

Try this for your layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
style="#style/AppTheme"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/list"
android:name="com.example.app.ItemFragment"
android:layout_width="0dp"
android:layout_height="0dp"
android:scrollbars="vertical"
app:layoutManager="LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:context=".ItemFragment"
tools:listitem="#layout/fragment_item" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/floatingActionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:layout_margin="#dimen/fab_margin"
android:clickable="true"
android:focusable="true"
android:src="#android:drawable/ic_input_add"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Inside ItemFragment.kt replace onCreateView with
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(R.layout.fragment_item_list, container, false)
}
After that go ahead and implement onViewCreated as such
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
with(list) {
layoutManager = when {
columnCount <= 1 -> LinearLayoutManager(requireContext())
else -> GridLayoutManager(requireContext(), columnCount)
}
adapter = MyItemRecyclerViewAdapter(DummyContent.ITEMS)
}
}
This should fix your problem because the AS template is assuming that the rootview will be a RecyclerView and is treating the whole layout as such.

How to implement RecyclerViewPager in kotlin?

I am trying to implement RecyclerViewPagerIndicator in my project, but I can't get it to work.
I work with Kotlin and AndroidX
I expect send a array with text and images from database and show in RecyclerViewPager, something like tinder.

I would suggest you to use dotsIndicator, since it
supports ViewPager 2 which is based on RecyclerView
is maintained, one you picked is not (project seems abandoned)
is written in Kotlin
Example:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
android:gravity="center"
tools:context=".MainActivity">
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/view_pager_2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<com.tbuonomo.viewpagerdotsindicator.WormDotsIndicator
android:id="#+id/dots_indicator"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"/>
</LinearLayout>
MainActivity.kt
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setupViewPager2()
}
private fun setupViewPager2() {
val viewPager2 = findViewById<ViewPager2>(R.id.view_pager_2)
val dotsIndicator = findViewById<WormDotsIndicator>(R.id.dots_indicator)
viewPager2.adapter = PagerAdapter(this)
dotsIndicator.setViewPager2(viewPager2)
}
}
PagerAdapter.kt
class PagerAdapter(fa:FragmentActivity): FragmentStateAdapter(fa) {
override fun getItemCount(): Int = 3
override fun createFragment(position: Int): Fragment {
return when(position){
0 -> SampleFragment.newInstance("One", "desc 1")
1 -> SampleFragment.newInstance("Two", "desc 2")
2 -> SampleFragment.newInstance("Three", "desc 3")
else -> throw Exception("No such position")
}
}
}
fragment_sample.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
android:gravity="center"
tools:context=".SampleFragment">
<TextView
android:id="#+id/txt_header"
tools:text="Header 1"
android:textAlignment="center"
android:textSize="24sp"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="#+id/txt_desc"
tools:text="Desc 1"
android:textAlignment="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
SampleFragment.kt
class SampleFragment : Fragment() {
private var header: String? = null
private var desc: String? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
arguments?.let {
header = it.getString(ARG_Header)
desc = it.getString(ARG_Desc)
}
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_sample, container, false)
setView(view)
return view
}
private fun setView(view:View){
val headerText = view.findViewById<TextView>(R.id.txt_header)
headerText.text = header
val descText = view.findViewById<TextView>(R.id.txt_desc)
descText.text = desc
}
companion object {
#JvmStatic
fun newInstance(param1: String, param2: String) =
SampleFragment().apply {
arguments = Bundle().apply {
putString(ARG_Header, param1)
putString(ARG_Desc, param2)
}
}
}
}