I'm just a hack and a newbie...I've received a lot of good information on this site but can't seem to find the answer to setting the max life cycle of a fragment, such that when it is selected, the onResume() for that fragment is executed.
I've created a simple 3-tab application from the help of youTube videos and haven't figured out to properly set the lifecycle. I'm not sure how much information I should include, so i'll start with this:
val tabLayout: TabLayout = findViewById(R.id.tab_layout)
val viewPager: ViewPager = findViewById(R.id.view_pager)
val viewPagerAdpater = ViewPagerAdapter(supportFragmentManager)
viewPagerAdpater.addFragment(SummaryFragment(), "Summary")
viewPagerAdpater.addFragment(BoxFragment(), "Box")
viewPagerAdpater.addFragment(SettingsFragment(), "Settings")
viewPager.adapter = viewPagerAdpater
tabLayout.setupWithViewPager(viewPager)
I've tried this, which crashes:
supportFragmentManager.beginTransaction().setMaxLifecycle(viewPagerAdpater.getItem(1),Lifecycle.State.RESUMED)
There is also this code:
internal class ViewPagerAdapter(fragmentManager: FragmentManager) : FragmentPagerAdapter(fragmentManager) {
private val fragments: ArrayList<Fragment>
private val titles: ArrayList<String>
init{
fragments = ArrayList<Fragment>()
titles = ArrayList<String>()
}
override fun getItem(position: Int): Fragment {
return fragments[position]
}
override fun getCount(): Int {
return fragments.size
}
fun addFragment(fragment: Fragment, title: String){
fragments.add(fragment)
titles.add(title)
}
override fun getPageTitle(i: Int): CharSequence? {
return titles[i]
}
}
Thanks and let me know if more information is required...
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I got crazy ı am not able find solution. Please help me. 2 days ı am looking for solution. I clearly watn that if I click any recylerView Item starting a new activity. Each item has to own its activity.How to implement codes?. Thanks in advance.
My adapter code:
class CustomAdapter(private val mList: List<ItemsViewModel>) : RecyclerView.Adapter<CustomAdapter.ViewHolder>() {
// create new views
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
// inflates the card_view_design view
// that is used to hold list item
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.card_view_design, parent, false)
return ViewHolder(view)
}
// binds the list items to a view
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val ItemsViewModel = mList[position]
// sets the image to the imageview from our itemHolder class
holder.imageView.setImageResource(ItemsViewModel.image)
// sets the text to the textview from our itemHolder class
holder.textView.text = ItemsViewModel.text
holder.itemView.setOnClickListener {
}
}
// return the number of the items in the list
override fun getItemCount(): Int {
return mList.size
}
// Holds the views for adding it to image and text
class ViewHolder(ItemView: View) : RecyclerView.ViewHolder(ItemView) {
val imageView: ImageView = itemView.findViewById(R.id.imageview)
val textView: TextView = itemView.findViewById(R.id.textView)
}
}
My recyclerview.kt :
class recyclerView : AppCompatActivity() {
private lateinit var binding: ActivityRecyclerViewBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityRecyclerViewBinding.inflate(layoutInflater)
setContentView(binding.root)
supportActionBar?.hide()
// getting the recyclerview by its id
val recyclerview = findViewById<RecyclerView>(R.id.recyclerview)
// this creates a vertical layout Manager
binding.recyclerview.layoutManager = LinearLayoutManager(this)
// ArrayList of class ItemsViewModel
val data = ArrayList<ItemsViewModel>()
data.add(ItemsViewModel(R.drawable.jumping_jack, "Jumping Jack"))
data.add(ItemsViewModel(R.drawable.jumping_aquats, "Jumping Squat"))
// This will pass the ArrayList to our Adapter
val adapter = CustomAdapter(data)
// Setting the Adapter with the recyclerview
recyclerview.adapter = adapter
}
}
If you put a list object to adapter like param, you can get position of item, and use this position to start activity you want.
something like this:
add listener in your adapter
class CustomAdapter(
private val mList: List<ItemsViewModel>,
val clickListener: RecycleViewOnClickListener
) : RecyclerView.Adapter<CustomAdapter.ViewHolder>() {
...
}
in your bindViewHolder:
override fun onBindViewHolder(holder:
RecyclerView.ViewHolder,position: Int) {
holder.itemView.setOnClickListener {
clickListener.onItemClick(position)
}
}
and add simple interface:
interface RecycleViewOnClickListener {
fun onItemCLick(position: Int)
}
in your activity, get model from list with your position:
class recyclerView : AppCompatActivity(), RecycleViewOnClickListener {
override fun onItemClick(pos: Int) {
val model = yourList[pos]
//start new activity
}
}
then when you init adapter:
// This will pass the ArrayList to our Adapter
val adapter = CustomAdapter(data, this)
You can do this by using high order function it will be easy
In you adapter class (pass list and high order function as callback)
class YourAdapter(private val itemList: List<Model>, private val onItemClicked: (item) -> Unit) :
RecyclerView.Adapter<RecyclerView.ViewHolder>() {
// your code
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
onItemClicked(itemList[position])
}
In your activity/Fragment where you are assigning adapter assign in this way.
whenever item is clicked it will land here, and you can start your activity, you will get item also from adapter on which user clicked
YourAdapter(list) { item ->
//start activity
}
Note: Always write some code with question, it will be easy for us to answer you and guide you what is wrong in your code.
Happy Coding!
I'm having trouble binding my ViewHolder, and I've got two warning that I believe are related. I am trying to use Hilt to create a clickable ViewHolder, so in my SessionAdapter I am using an inner class to bind my SessionViewHolder to my RecyclerView.
First, I am struggling to understand what to return for the inner class SessionViewHolder fun bind(session: Session) { ...}. Android Studio is telling me function "bind" is never used, but I thought I used it in my onBindViewHolder?
Secondly, in my override onBindViewHolder I don't understand how I should use val session?
#AndroidEntryPoint
class SessionFragment : Fragment() {
var adapter: SessionAdapter = SessionAdapter()
private val sessionAdapter = SessionListAdapter(this::onSessionClicked)
private fun onSessionClicked(session: Session): Session {
return(session)
}
class SessionAdapter {
fun setOnClickListener() {
return(addSessionToItinerary())
}
private fun addSessionToItinerary() {
return addSessionToItinerary()
}
}
class SessionListAdapter(
private val onSessionCLicked: (Session) -> Unit,
) : ListAdapter<Session, SessionListAdapter.SessionViewHolder>(SessionItemCallback) {
inner class SessionViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun bind() {
val textView = itemView.findViewById<TextView>(0)
fun bind(session: Session) {
textView.text = session.title
itemView.setOnClickListener {
onSessionCLicked(session)
return#setOnClickListener
}
}
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SessionViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val itemView = layoutInflater.inflate(R.layout.fragment_session_list, parent, false)
return SessionViewHolder(itemView)
}
override fun onBindViewHolder(holder: SessionViewHolder, position: Int) {
val session = getItem(position)
holder.bind()
}
}
Thank you in advance for you help. I have gotten myself confused with the recurrence of bind and session throughout my adapter.
See here in this code, you have defined two bind functions, but one is nested inside the other so it is unusable:
fun bind() {
val textView = itemView.findViewById<TextView>(0)
fun bind(session: Session) {
textView.text = session.title
itemView.setOnClickListener {
onSessionCLicked(session)
return#setOnClickListener
}
}
}
The outer bind() function is the one you are calling, and it doesn't make sense to bind nothing. This function gets a reference to a TextView, and it creates a function that is never used.
Another problem is that you are passing 0 to findViewById. There is never going to be a view with an ID of 0. You need to pass R.id.whateverYourTextViewIsNamedInYourXml.
Side note, return#onClickListener is unnecessary. If a function doesn't return anything, putting a return statement on the last line doesn't do anything.
To make it work, you should replace the above code with something like this, but replace the name of the text view with whatever ID you assigned it in your XML:
fun bind(session: Session) {
val textView = itemView.findViewById<TextView>(R.id.myTextView)
textView.text = session.title
itemView.setOnClickListener {
onSessionCLicked(session)
}
}
and then pass the session to this function when you call it.
Side note, your SessionAdapter class doesn't make any sense at all, but you're not using it for anything anyway. I would delete that.
I want to set the adapter of ViewPager2 to FragmentStatePagerAdapter but I get this error:
Type mismatch. Required: (RecyclerView.Adapter<RecyclerView.ViewHolder!>?..RecyclerView.Adapter<*>?) Found: ViewPager2Adapter
My ViewPagerAdapter class is
class ViewPager2Adapter(fm:FragmentManager) :FragmentStatePagerAdapter(fm) {
override fun getItem(position: Int): Fragment {
return when(position) {
0 -> {
MyScansListFragment()
}
1 -> {
PurchasedItemsFragment()
}
else -> {
Fragment()
}
}
}
override fun getCount(): Int {
return 2
}
override fun getItemPosition(`object`: Any): Int {
return POSITION_NONE
}}
And in the oncreateView() :
val viewPager2Adapter = ViewPager2Adapter(activity?.supportFragmentManager!!)
binding!!.viewPager.adapter = viewPager2Adapter
okay, let's change the code a little bit.
First of all, FragmentStatePagerAdapter has been deprecated.
FragmentStatePagerAdapter & FragmentPagerAdapter have been recently deprecated, and your code must look something like this. FragmentStatePagerAdapter and if you get your cursor over it and see details, there will be a statement "Deprecated Switch to androidx.viewpager2.widget.ViewPager2 and use androidx.viewpager2.adapter.FragmentStateAdapter instead."
try the following code.
class ViewPager2Adapter(private val listFragment: ArrayList<Fragment>,
fm: FragmentManager,
lifecycle: Lifecycle) : FragmentStateAdapter(fm, lifecycle) {
override fun getItemCount(): Int {
return listFragment.size
}
override fun createFragment(position: Int): Fragment {
return listFragment[position]
}
}
so, this is now kind of your universal viewpager adapter.
The next thing is we require fragments to be passed in here.
//I don't think you need Fragment() but since it's there in your list.
val fragmentList = listOf(MyScansListFragment(), PurchasedItemsFragment(),Fragment())
val viewPager2Adapter = ViewPager2Adapter(fragmentList, activity?.supportFragmentManager!!, lifecycle)
binding!!.viewPager.adapter = viewPager2Adapter
I have created a simple notes app that uses some of the Android Architecture components. I am using dataBinding to set data to my recycler view. One of the functionalities is bookmarking a note and displaying it in the Bookmarks fragment. In the Bookmarks fragment a user can tap the 'unbookmark' icon to remove a bookmarked note. I have used a simple on click listener on the icon inside my Bookmarks Recycler View Adapter to achieve this. I have a boolean property in my notes entity. Inside the Bookmarks fragment I update the bookmarks boolean value to false when the user taps the icon so that it changes to a false value(meaning it's not bookmarked and does not appear in the bookmarks fragment). However, when I click the 'unbookmark' icon the recycler view still displays the notes removed from the bookmarks.
Here is my Bookmarks Adapter :
class BookmarksAdapter(private var bookmarksList: List<Note>, var context: Context):
RecyclerView.Adapter<BookmarksAdapter.BookmarkViewHolder>(), CoroutineScope {
private lateinit var job: Job
var deletedId : Int? = null
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BookmarkViewHolder {
val layoutItemBinding: BookmarksLayoutItemBinding = DataBindingUtil.inflate(
LayoutInflater.from(parent.context),
R.layout.bookmarks_layout_item,
parent,
false)
job = Job()
return BookmarkViewHolder(layoutItemBinding.root)
}
override fun onBindViewHolder(holder: BookmarkViewHolder, position: Int) {
val bookmarkNote: Note = bookmarksList.get(position)
holder.bookmarkBinding?.setVariable(BR.bookmarkItem, bookmarkNote)
holder.bookmarkBinding?.executePendingBindings()
holder.bookmarkBinding?.imageRemoveBookmark?.setOnClickListener {
removeBookmark(bookmarkNote, position)
}
}
override fun getItemCount(): Int {
return bookmarksList.size
}
inner class BookmarkViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var bookmarkBinding: BookmarksLayoutItemBinding? = DataBindingUtil.bind(itemView)
}
override val coroutineContext: CoroutineContext
get() = job + Dispatchers.Main
fun deleteNote(note : Note) {
launch(Dispatchers.IO) {
note.isBookmarked = false
NotesDatabase(context).getDao().updateNote(note)
}
val pos = bookmarksList.toMutableList().indexOf(note)
bookmarksList.toMutableList().removeAt(pos)
notifyItemRemoved(pos)
}
// Remove a bookmark
fun removeBookmark(bookmarkNote: Note, removedPos: Int) {
bookmarkNote.isBookmarked = false
launch (Dispatchers.IO){
NotesDatabase(context).getDao().updateNote(bookmarkNote)
withContext(Dispatchers.Main) {
bookmarksList.toMutableList().removeAt(removedPos)
notifyItemRemoved(removedPos)
notifyItemRangeChanged(removedPos, 1)
}
}
}
}
Below is my Bookmarks View Model:
class BookmarksViewModel(application: Application) : AndroidViewModel(application) {
val myContext: Context = application.applicationContext
private var _bookmarksList = MutableLiveData<List<Note>>()
val bookmarksList : LiveData<List<Note>>
get() = _bookmarksList
init{
viewModelScope.launch {
_bookmarksList.value = getNotes()
}
}
suspend fun getNotes() : List<Note> = NotesDatabase(myContext).getDao().getBookmarkedNotes()
}
Here is my Bookmarks Fragment:
class BookmarksFragment : BaseFragment(){
private lateinit var bookmarksBinding: FragmentBookmarksBinding
private lateinit var bookmarksViewModel: BookmarksViewModel
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
bookmarksBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_bookmarks, container, false)
bookmarksViewModel = ViewModelProvider(this).get(BookmarksViewModel::class.java)
// Observe the list of bookmarks
bookmarksViewModel.bookmarksList.observe(viewLifecycleOwner, { bList ->
bookmarksBinding.listOfBookmarks = bList
})
return bookmarksBinding.root
}
}
Here is my Notes Entity:
val bookmarkSate: Boolean
get() = true
#Entity
data class Note(
val title : String,
val note : String,
var isBookmarked : Boolean = false
) : Serializable{
#PrimaryKey(autoGenerate = true)
var noteID : Int = 0
}
Here is my Notes DAO:
#Dao
interface NoteDao {
#Insert
suspend fun saveNote(note : Note)
#Query("SELECT * FROM note ORDER BY noteID DESC")
suspend fun getAllNotes() : List<Note>
#Query("SELECT * FROM note WHERE isBookmarked")
suspend fun getBookmarkedNotes() : List<Note>
// add multiple notes
#Insert
suspend fun addMultipleNotes(vararg note: Note)
#Update
suspend fun updateNote(note: Note)
#Delete
suspend fun deleteNote(note : Note)
}
I am stuck on how to achieve the desired functionality of 'unbookmarking' a note and making it 'disappear 'from the bookmarks fragment. Kindly anyone who can help out?
There are a few problems and possible solutions I see here:
1-) In your adapter, in your delete method, you have this piece of code:
val pos = bookmarksList.toMutableList().indexOf(note)
bookmarksList.toMutableList().removeAt(pos)
notifyItemRemoved(pos)
The problem here is that toMutableList() doesn't change your bookmarksList as mutable, it returns a new mutable list filled with the items in your bookmarkList, a mutable version of your list, but a new list! So you remove the item from this new list, and not from the original list. Simply correcting this could fix the problem. (You can define the bookmarksList as a mutable list from the beginning)
2-) You seem to observe the list from your viewmodel, it is livedata in your viewmodel. But it is not defined as livedata in your dao. So you are not observing the changes in the database. So an alternative solution could be to observe the changes from the database by wrapping your list within a livedata in your dao.
#Query("SELECT * FROM note WHERE isBookmarked")
suspend fun getBookmarkedNotes() : LiveData<List<Note>>
But this second one would require some additional changes in your code.
I want to get input from the user using EditText and pass it to server and show the response to the user. I do this simply without any architecture but I would like to implement it in MVVM.
this is my repository code:
class Repository {
fun getData(context: Context, word: String): LiveData<String> {
val result = MutableLiveData<String>()
val request = object : StringRequest(
Method.POST,
"https://jsonplaceholder.typicode.com/posts",
Response.Listener {
result.value = it.toString()
},
Response.ErrorListener {
result.value = it.toString()
})
{
#Throws(AuthFailureError::class)
override fun getParams(): MutableMap<String, String> {
val params = HashMap<String, String>()
params["word"] = word
return params
}
}
val queue = Volley.newRequestQueue(context)
queue.add(request)
return result
}
}
and these are my View Model codes:
class ViewModel(application: Application) : AndroidViewModel(application) {
fun getData(word: String): LiveData<String> {
val repository = Repository()
return repository.getData(getApplication(), word)
}
}
and my mainActivity would be like this:
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val model = ViewModelProviders.of(this).get(ViewModel::class.java)
model.getData("test").observe(this, Observer {
Log.i("Log", "activity $it")
})
}
}
My layout has an EditText which I want to get user input and pass it to the server, how should i do that?
Here how i did it in my projet.
You can probably use android annotations.
It's gonna requiere you to put some dependencies and maybe change the class a bit, but then you gonna link your Viewmodel with your repository and then you gonna have to program the setter of the variable to do a notifyChange() by making the class herited from BaseObservable. Then in the xml, if you did the correctly, you should be able to do a thing like text:"#={model.variable}" and it should be updating at the same time.
A bit hard and explain or to show for me sorry, but i would look into Android Annotations with #DataBinding, #DataBound :BaseObservable
https://github.com/androidannotations/androidannotations/wiki/Data-binding-support
Hope that can help a bit!