In my application i want show message when fragment has show.
I used viewPager and BottomNavBar for show 4 fragments!
I want when click on BottomNavBar items show fragment and i want when visibility fragment show message.
I write below codes :
class HomeRegisteredFragment : Fragment() {
lateinit var toolbarTile: TextView
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_home_registered, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//Initialize
activity?.let {
toolbarTile = it.findViewById(R.id.homePage_toolbarTitle)
}
//Set title
toolbarTile.text = resources.getString(R.string.registered)
context?.let { ContextCompat.getColor(it, R.color.blue_active) }?.let {
toolbarTile.setTextColor(it)
}
}
override fun setUserVisibleHint(isVisibleToUser: Boolean) {
super.setUserVisibleHint(isVisibleToUser)
if (isVisibleToUser) {
Log.e("showFragLog", "Show")
context?.let { Toast.makeText(it, "Show", Toast.LENGTH_SHORT).show() }
}
}
}
In my above codes, when click on my BottomNavBar for show fragment, show me Log message but not show Toast message.
When click on another BottomNavBar items and again click on previous BottomNavBar item, then show Toast message.
I think in first time not initialize context in setUserVisibleHint method.
How can i initialize context for show Toast in every time?
I changed your codes with below codes :
class HomeRegisteredFragment : Fragment() {
lateinit var toolbarTile: TextView
lateinit var handler: Handler
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_home_registered, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//Initialize
activity?.let {
toolbarTile = it.findViewById(R.id.homePage_toolbarTitle)
}
}
override fun setUserVisibleHint(isVisibleToUser: Boolean) {
super.setUserVisibleHint(isVisibleToUser)
if (isVisibleToUser) {
//Initialize
handler = Handler()
//Set delay
handler.postDelayed({
Toast.makeText(requireContext(),"Show",Toast.LENGTH_SHORT).show()
}, 10)
}
}
}
First you should use requireContext() instead of context() for avoid from memory leak.
For show Toast for every time, you can initialize handler in setUserVisibleHint , then after some delay run your code!
I hope help you
Storing context in a variable is a horrible practive and most of the times leads to memory leaks, use requireContext() this method was introduced in Support Library 27.1.0. Nowdays most likely you will have a newer version or even using androidx so there is no excuse for storing a context
If you are looking for application context to show the toast message, try the below way and see if it works. Also, initialize it onCreate method so you have the activity context at that point.
val appContext = context!!.applicationContext
O have a similar trouble here. I have one Activity with multiple Fragments, and I need a ListView to show some employes.
But when I call the Adapter class, I don't know how to pass the context variable:
binding.listviewCoordenacoes.isClickable = true
binding.listviewCoordenacoes.adapter = CoordenadorAdapter(requireContext().applicationContext as Activity, arrayListCoordenador)
binding.listviewCoordenacoes.setOnClickListener{}
In the examples in general, it works in Activities. If not possible, I will create an Activity and put it in that.
Related
I have been doing a tutorial that is a bit out of date and uses synthetics rather than bindings. I am trying to use bindins. I am trying to set up a listener in a fragment (AddEditFragment.kt). It's using a callback to MainActivity.onSaveClicked.
In AddEditFragment I use an import for the binding
import com.funkytwig.tasktimer.databinding.FragmentAddEditBinding
I have a lateinit on the first line of the class defenition
class AddEditFragment : Fragment() {
private lateinit var binding: FragmentAddEditBinding
I am initializing the bunding in onActivityCreated and setting up the listner. I can use findViewById to get the ID
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val addEditSave = view?.findViewById(R.id.addEditSave) as Button
addEditSave.setOnClickListener { listener?.onSaveClicked() }
}
And this works fine but if I try to use the binding
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
binding.addEditSave.setOnClickListener { listener?.onSaveClicked() }
}
The code does not show any errrors but it does not seem to create the listner. I have a Log.d in the onSaveClicked callback function and when I use the first (findViewById) version of the function it works (it calles onSaveClicked) but with the second version (using bindings) onSaveClicked does not get called when I click the Button.
I Cant figre out why the second version does not work, I thought the two versions of onActivityCreated should do the same thing.
The interface in AddEditFragment.kt is
interface OnSaveClicked {
fun onSaveClicked()
}
In fragment you should add your view in onCreateView or in OnViewCreated not in onActivityCreated
Please refer link for more details.
private var _binding: FragmentAddEditBinding? = null
// This property is only valid between onCreateView and
// onDestroyView.
private val binding get() = _binding!!
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
_binding = FragmentAddEditBinding.inflate(inflater, container, false)
val view = binding.root
binding.addEditSave.setOnClickListener { listener?.onSaveClicked() }
return view
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
OK, thanks for all the help. turned out I was doing the inflate wrong.
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
Log.d(TAG, "onCreateView")
binding = FragmentAddEditBinding.inflate(layoutInflater, container, false)
return binding.root
}
I was doing
binding = FragmentAddEditBinding.inflate(layoutInflater)
I missed out on the last 2 args as I was taking the code from the inflate when I am in an Activity, not a Fragment. I think it is to do with the layout effecticly being in the parent.
In my application I have some fragments and for show this fragments I want use NavigationComponent.
I have one problem. When click on BottomNavigationItems and change fragments, run again fragment code!
I want just run codes just for first time!
My codes (for one of fragments) :
#AndroidEntryPoint
class HomeNewFragment : Fragment(), HomeContracts.View {
//Binding
private lateinit var binding: FragmentHomeNewBinding
#Inject
lateinit var presenter: HomePresenter
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
binding = FragmentHomeNewBinding.inflate(layoutInflater)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//InitViews
binding.apply {
//Call apis
presenter.callApi()
}
}
}
For example when click on items, every time call this code : presenter.callApi()
Or when go to DetailFragment and when click on back, again call presenter.callApi()
How can I fix it?
You should replace your presenter.callApi() with fun onFragmentCreated triggered in your Presenter(ViewModel).
All you need is a boolean var to check its first time or not cause your Presenter(ViewModel) attatched to the activity, not the fragment so it can store your state.
Presenter {
fun onFragmentCreated() {
if(firstTime) callApi()
I have a fragment that I want to display as an embedded fragment in a ViewPager and as a Bottom Sheet. I followed this https://developer.android.com/reference/android/app/DialogFragment#DialogOrEmbed and created a DialogFragment
private val mViewModel: CardPricesViewModel by viewModels()
private val binding by viewBinding(FragmentCardDetailPricesBinding::inflate)
companion object {
// This is the same value as the navArg name so that the SavedStateHandle can acess from either
const val ARG_SKU_IDS = "skuIds"
fun newInstance(skus: List<Long>?) =
CardDetailPricesFragment().apply {
arguments = Bundle().apply {
putLongArray(ARG_SKU_IDS, skus?.toLongArray())
}
}
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
}
}
However, when it gets inflated in a ViewPager the background dims as though it is a BottomSheetDialogFragment
However, when I manually do it with
supportFragmentManager
.beginTransaction()
.replace(binding.cardPricesFragmentContainer.id, cardDetailPricesFragment)
.commit()
It works fine. I see that the FragmentStateAdapter uses FragmentViewHolders instead of the using transactions directly (?), so I am not sure how to resolve this issue. I see that onCreateDialog() is being called, so if I call dismiss() after onViewCreated(), it works properly, but I am not sure if this a workaround
After some digging, I found the DialogFragment.setShowsDialog(boolean) method that you can use to disable the dialog being created.
I know there is a lateinit or lazy keyword in Kotlin to prevent indiscriminate initialization and thus minimize wasted resources.
I wanted to use the lazy keyword to use findViewById when necessary events occur.
However, if I use the lazy keyword, nothing happens. It doesn't even cause an error.
Conversely, when findViewId is normally used in onCreateView, click event occurs normally.
Why doesn't lazy work?
class BodyPartDialogFragment : DialogFragment(), View.OnClickListener{
private val ll: LinearLayout? by lazy { view?.findViewById(R.id.ll_body_part) }
// private lateinit var button: Button
private val button: Button? by lazy { view?.findViewById(R.id.start) }
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view: View = inflater.inflate(R.layout.fragment_body_part_dialog, container, false)
// ll = view.findViewById(R.id.ll_body_part)
// button = view.findViewById(R.id.start)
ll?.apply { clipToOutline = true }
button?.setOnClickListener { // Nothing Happened
Toast.makeText(context, "Noting Selected", Toast.LENGTH_SHORT).show()
}
return view
}
getView() that is behind the view property returns whatever you returned from onCreateView(). When you access view inside onCreateView(), it hasn't yet returned anything and hence a null is returned, and your ?. safecall becomes a no-op.
You can use a lazy approach like this after onCreateView(), such as in onViewCreated().
It looks like you may be initializing things in the wrong order.
Consider that renaming a local variable always preserves semantics, so let's modify your code a little:
private val ll: LinearLayout? by lazy { view?.findViewById(R.id.ll_body_part) }
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val someRandomView: View = inflater.inflate(R.layout.fragment_body_part_dialog, container, false)
ll?.apply { clipToOutline = true }
button?.setOnClickListener { // Nothing Happened
Toast.makeText(context, "Noting Selected", Toast.LENGTH_SHORT).show()
}
return someRandomView
}
Do you see the issue? ll is being initialized with a view that hasn't been assigned yet in onCreateView.
view (or really getView()) is the view that is returned from onCreateView(). You're trying to access that before you have returned from onCreateView() so it returns null, and your lazy value is then also null. You can make this work by accessing it later, ie. in onViewCreated()
class BodyPartDialogFragment : DialogFragment(), View.OnClickListener{
private val ll: LinearLayout? by lazy { view?.findViewById(R.id.ll_body_part) }
// private lateinit var button: Button
private val button: Button? by lazy { view?.findViewById(R.id.start) }
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view: View = inflater.inflate(R.layout.fragment_body_part_dialog, container, false)
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
ll?.apply { clipToOutline = true }
button?.setOnClickListener { // Nothing Happened
Toast.makeText(context, "Noting Selected", Toast.LENGTH_SHORT).show()
}
}
}
This is more clear if you use requireView() since it returns a non-null View and rather throws an exception, so your app would have crashed with the error message did not return a View from onCreateView() or this was called before onCreateView().
You can do this to get access to View in the future using 'by lazy'
private val previewImage by lazy { requireActivity().findViewById<ImageView>(R.id.ivImage) }
Then you can use it like
previewImage.setImageURI(imageUri)
I am developing an app with Firebase. But whenever I use the onViewCreated method, the button does not respond to any clicks. But when I use the onCreateView, it works.
Here is my LoginFragment (Button does not respond to clicks):
class LoginFragment : Fragment(R.layout.fragment_login) {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
val binding = FragmentLoginBinding.inflate(layoutInflater)
binding.buttonGoogleSignin.setOnClickListener {
toast("THIS IS NOT WORKING")
Authentication.getInstance().signIn(context!!, getString(R.string.default_web_client_id)) {
startActivityForResult(mGoogleClient.signInIntent, RC_GOOGLE_SIGN_IN)
}
}
}
}
In this code, my button responds to clicks:
class LoginFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInFlater,
container: ViewGroup?,
savedInstanceState: Bundle?
) {
val view = inflater.inflate(R.layout.fragment_login, container, false)
val binding = FragmentLoginBinding.bind(view)
binding.buttonGoogleSignin.setOnClickListener {
toast("THIS IS WORKING")
Authentication.getInstance().signIn(context!!, getString(R.string.default_web_client_id)) {
startActivityForResult(mGoogleClient.signInIntent, RC_GOOGLE_SIGN_IN)
}
}
return view
}
}
Can someone explain to me why the first approach did not work?
The problem is in the fact that in onViewCreated you are creating a binding object with FragmentLoginBinding.inflate(layoutInflater) but you are not connecting that binding to the view, so whatever you do with that object will not have effect on the view.
FragmentLoginBinding.inflate(layoutInflater) creates a new binding object and also inflate a new view to which it is connected. But you are not using that view in your fragment, so using that method is not the correct choice.
So you can do something like:
val binding = FragmentLoginBinding.bind(getView())
inside onViewCreated if you really want, and that will create a binding with the view you have in your fragment.
Said that, creating the binding already in onCreateView is actually recommended by the Android documentation.