Develop Reference

Duplicate and overlapping text in TextView when using LiveData or StateFlow

To be as clear as possible, I'm going to show the problem with a gif.
As you can see, the text is overlapping in my emulator and I don't know how to solve it, I don't know what I'm doing wrong.
It should be displayed correctly without overlapping. What I'm doing is subscribing to changes in both LiveData and StateFlow. When I press the button, I make it change the value, but instead of changing, it seems to return both values at once (Default and Hello). Could it be that the view is not refreshing? Or could it be a problem with my emulator?
Anyway, I'll leave all the code here in case you can figure it out.
FlowsFragment.kt
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.View
import androidx.fragment.app.viewModels
import androidx.lifecycle.lifecycleScope
import com.rr.stateflow_livedata_flow_sharedflow.databinding.FragmentFlowsBinding
import kotlinx.coroutines.flow.collectLatest
class FlowsFragment : Fragment(R.layout.fragment_flows) {
private lateinit var binding: FragmentFlowsBinding
private val viewModel: FlowsViewModel by viewModels()
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding = FragmentFlowsBinding.bind(view)
binding.btnLiveData.setOnClickListener {
viewModel.triggerLiveData()
}
binding.btnStateFlow.setOnClickListener {
viewModel.triggerStateFlow()
}
subscribeToObservables()
}
private fun subscribeToObservables() {
viewModel.liveData.observe(viewLifecycleOwner) {
binding.tvLiveData.text = it
}
lifecycleScope.launchWhenStarted {
viewModel.stateFlow.collectLatest {
binding.tvStateFlow.text = it
}
}
}
}
FlowsViewModel.kt
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import kotlinx.coroutines.flow.*
class FlowsViewModel : ViewModel() {
private val _liveData = MutableLiveData("Default LiveData")
val liveData: LiveData<String> = _liveData
private val _stateFlow = MutableStateFlow("Default StateFlow")
val stateFlow: StateFlow<String> = _stateFlow.asStateFlow()
fun triggerLiveData() {
_liveData.value = "Hello LiveData!"
}
fun triggerStateFlow() {
_stateFlow.value = "Hello StateFlow!"
}
}
fragment_flows.xml
<?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"
tools:context=".FlowsFragment">
<TextView
android:id="#+id/tvLiveData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/btnLiveData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="LIVEDATA"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvLiveData" />
<TextView
android:id="#+id/tvStateFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnLiveData" />
<Button
android:id="#+id/btnStateFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="STATEFLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvStateFlow" />
<TextView
android:id="#+id/tvFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.504"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnStateFlow" />
<Button
android:id="#+id/btnFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="FLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvFlow" />
<TextView
android:id="#+id/tvSharedFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnFlow" />
<Button
android:id="#+id/btnSharedFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="SHAREDFLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvSharedFlow" />
</androidx.constraintlayout.widget.ConstraintLayout>
I hope that the text doesn't overlap and returns the latest value of LiveData and StateFlow.
Edit with more info: The application displays the view directly from the fragment, MainActivity only has a fragment container that I show below.
MainActivity.kt
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.add
import androidx.fragment.app.commit
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
supportFragmentManager.commit {
setReorderingAllowed(true)
add<FlowsFragment>(R.id.mainActivityFragmentContainer)
}
}
}
activity_main.xml
<?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"
tools:context=".MainActivity">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/mainActivityFragmentContainer"
android:name="com.rr.stateflow_livedata_flow_sharedflow.FlowsFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:layout="#layout/fragment_flows" />
</androidx.constraintlayout.widget.ConstraintLayout>

EDIT This is not the solution, it's a bad way to solve the problem.
I just have to add this line of code in fragment_flows.xml.
android:background="#color/white"
Just by setting the background of the fragment to white, the text is no longer duplicated and overlapping.
Does anyone know why this happens? Why does what is drawn on the screen stick to the background if there is no background in the fragment layout?

Populate UI from a ViewModel in Kotlin

This is the first time I am using Android Architecture. I have decided to go with MVVM structure but I am stuck at the point where I have no idea how to set the textViews in my XML with the data I pull from the database.
Checking the logs, I have seen that the function calls to my database (Firestore) does retrieve the correct data documents. Do I set the UI elements from the Activity,ViewModel or the Fragment? (Please note that I'm using a Navigation bar and controller)
Please assist me, my code is as follows:
My Single Activity:
class HomeActivity : AppCompatActivity() {
// Create the three objects for the fragments
lateinit var homeFragment: HomeFragment
lateinit var visitsFragment: VisitsFragment
lateinit var profileFragment: ProfileFragment
// ViewModels
lateinit var customerViewModel: CustomerViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_home)
// Initialize the bottom nav bar and navigation controller and then merge them
val bottomNavigationView = findViewById<BottomNavigationView>(R.id.btm_nav)
val navigationController = findNavController(R.id.fragmentHost)
bottomNavigationView.setupWithNavController(navigationController)
// Create app bar config object so that you can rename the bar ontop with the tab name
val appBarConfiguration = AppBarConfiguration(setOf(R.id.homeFragment,R.id.visitsFragment,R.id.profileFragment))
setupActionBarWithNavController(navigationController,appBarConfiguration)
// View Model
customerViewModel = ViewModelProvider(this).get(CustomerViewModel::class.java)
customerViewModel.retrieveCustomer().observe(this, Observer { it })
}
// This function creates the menu object by inflating it with the resource we gave it (menu resource).
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menuInflater.inflate(R.menu.menu_main,menu);
return true
}
// This function checks which menu item was selected and performs the task associated with the item selected.
override fun onOptionsItemSelected(item: MenuItem): Boolean {
val id = item.itemId;
// If Log Out menu item was selected
if (id == R.id.menuLogOut){
// Sign the user out
FirebaseAuth.getInstance().signOut()
// Finish this activity
finish()
// Start the initial activity
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
// Display the message to the user
Toast.makeText(this, "Successfully Signed Out", Toast.LENGTH_SHORT).show()
return true
}
return super.onOptionsItemSelected(item)
}
}
My View Model:
class CustomerViewModel: ViewModel() {
val TAG = "CustomerViewModel"
var db = Firebase.firestore
var user = FirebaseAuth.getInstance().currentUser
var liveData = MutableLiveData<List<Customer>>()
var cusArray = arrayListOf<Customer>()
var docRef = user?.uid
fun retrieveCustomer(): MutableLiveData<List<Customer>>
{
db.collection("users").document(docRef.toString())
.get()
.addOnSuccessListener { document ->
if (document != null)
{
val data = document
// Set the data
val name = data.get("name") as String
val surname = data.get("surname") as String
val email = data.get("email") as String
val contactNo = data.get("contact no") as String
val customer = Customer(name, surname, email, contactNo)
cusArray.add(customer)
liveData.value = cusArray
Log.d(TAG, "DocumentSnapshot data: ${document.data}")
}
else
{
Log.d(TAG, "No such document")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "get failed with " + exception.message, exception)
}
return liveData
}
}
My Object Class
package com.CleanWheels.cleanwheels.DataClasses
data class Customer(
val name: String?,
val surname: String?,
val email: String?,
val contactNo: String?
)
My XML file (profile_fragment):
<?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"
tools:context=".Fragments.ProfileFragment">
<TextView
android:id="#+id/banner"
android:layout_width="499dp"
android:layout_height="290dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginStart="-6dp"
android:layout_marginTop="0dp"
android:layout_marginEnd="0dp"
android:background="#color/colorPrimary"
android:layout_marginLeft="-6dp"
android:layout_alignParentRight="true"
android:layout_alignParentLeft="true"
android:layout_marginRight="0dp" />
<ImageView
android:id="#+id/image"
android:layout_width="154dp"
android:layout_height="159dp"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="53dp"
android:layout_marginEnd="132dp"
android:layout_marginRight="132dp"
android:layout_marginBottom="78dp"
android:src="#drawable/ic_action_profile" />
<LinearLayout
android:id="#+id/layout_1"
android:layout_width="280dp"
android:layout_height="40dp"
android:layout_below="#id/banner"
android:layout_marginLeft="80dp"
android:layout_marginTop="100dp"
android:layout_marginRight="20dp"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Name:"
android:textSize="18sp"/>
<TextView
android:id="#+id/profileNameUI"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="18sp"/>
</LinearLayout>
<LinearLayout
android:id="#+id/layout_2"
android:layout_width="280dp"
android:layout_height="40dp"
android:layout_below="#id/layout_1"
android:layout_marginLeft="80dp"
android:layout_marginTop="20dp"
android:layout_marginRight="20dp"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Surname:"
android:textSize="18sp"/>
<TextView
android:id="#+id/profileSurnameUI"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="18sp"/>
</LinearLayout>
<LinearLayout
android:id="#+id/layout_3"
android:layout_width="280dp"
android:layout_height="40dp"
android:layout_below="#id/layout_2"
android:layout_marginLeft="80dp"
android:layout_marginTop="20dp"
android:layout_marginRight="20dp"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Email Address:"
android:textSize="18sp"/>
<TextView
android:id="#+id/profileEmailUI"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="18sp"/>
</LinearLayout>
<LinearLayout
android:id="#+id/layout_4"
android:layout_width="280dp"
android:layout_height="40dp"
android:layout_below="#id/layout_3"
android:layout_marginLeft="80dp"
android:layout_marginBottom="50dp"
android:layout_marginTop="20dp"
android:layout_marginRight="20dp"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Contact No:"
android:textSize="18sp" />
<TextView
android:id="#+id/profileContactUI"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="18sp" />
</LinearLayout>
<LinearLayout
android:id="#+id/layout_5"
android:layout_width="65dp"
android:layout_height="220dp"
android:layout_below="#id/banner"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_marginStart="0dp"
android:layout_marginLeft="0dp"
android:layout_marginTop="90dp"
android:orientation="vertical">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="0dp"
android:layout_marginBottom="5dp"
android:layout_weight="1"
android:src="#drawable/ic_action_profile_name_ui"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp"
android:layout_weight="1"
android:src="#drawable/ic_action_profile_surname_ui"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp"
android:layout_weight="1"
android:src="#drawable/ic_action_profile_email_ui"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:layout_marginBottom="0dp"
android:layout_weight="1"
android:src="#drawable/ic_action_profile_contact_ui"/>
</LinearLayout>
The profile_fragment class file:
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"
/**
* A simple [Fragment] subclass.
* Use the [ProfileFragment.newInstance] factory method to
* create an instance of this fragment.
*/
class ProfileFragment : Fragment() {
// TODO: Rename and change types of parameters
private var param1: String? = null
private var param2: String? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
arguments?.let {
param1 = it.getString(ARG_PARAM1)
param2 = it.getString(ARG_PARAM2)
}
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_profile, container, false)
}
companion object {
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment ProfileFragment.
*/
// TODO: Rename and change types and number of parameters
#JvmStatic
fun newInstance(param1: String, param2: String) =
ProfileFragment().apply {
arguments = Bundle().apply {
putString(ARG_PARAM1, param1)
putString(ARG_PARAM2, param2)
}
}
}
}
Then finally, the View I am trying to populate

You need to move all the logic to ProfileFragment once you navigate to ProfileFragment data will be set.
Example:
ProfileFragment
class ProfileFragment : Fragment() {
private val customerViewModel: CustomerViewModel by viewModels()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val view = inflater.inflate(R.layout.fragment_profile, container, false)
val name = view.findViewById<TextView>(R.id.name)
val surname = view.findViewById<TextView>(R.id.surname)
val email = view.findViewById<TextView>(R.id.email)
val contact = view.findViewById<TextView>(R.id.contact)
//calling initially here
customerViewModel.retrieveCustomer()
customerViewModel.liveData.observe(viewLifecycleOwner, Observer {
//customer index at 0
val customer = it[0]
name.text = customer.name
surname.text = customer.surname
email.text = customer.email
contact.text = customer.contactNo
})
return view
}
CustomerViewModel.kt
class CustomerViewModel(application: Application) : AndroidViewModel(application) {
var liveData = MutableLiveData<List<Customer>>()
fun retrieveCustomer(){
//Your logic to get data from Firebase or any remote or db
val listOfCustomer = mutableListOf<Customer>()
val customer = Customer("name", "surname","email", "contqct")
listOfCustomer.add(customer)
liveData.postValue(listOfCustomer)
}
}
fragment_profile.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:padding="8dp"
android:textSize="24dp"
/>
<TextView
android:id="#+id/surname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Surname"
android:padding="8dp"
android:textSize="24dp"
/>
<TextView
android:id="#+id/email"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:padding="8dp"
android:textSize="24dp"
/>
<TextView
android:id="#+id/contact"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:padding="8dp"
android:textSize="24dp"
/>
</LinearLayout>

BindingImpl class for fragment not generated when using data binding onClick expression

In my Fragments layout I have a button which is using the XML onClick expression to call a method in the corresponding ViewModel.
The problem is that upon building the project, the compiler throws following error:
error: cannot find symbol
import com.aresid.myapp.databinding.FragmentLoginBindingImpl;
^
symbol: class FragmentLoginBindingImpl
location: package com.aresid.myapp.databinding
The thing is that, when I remove the parameters from the functions signature and the functions call in the XML, the app builds without problems.
My expectation is that, when I click the login button, the method in the ViewModel would be called, logging the emailField.text and passwordField.text.
The layout file:
<?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"
>
<data>
<variable
name="loginViewModel"
type="com.aresid.myapp.login.LoginViewModel"
/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/fragmentPaddingMedium"
tools:context=".login.LoginFragment"
>
<ImageView
android:id="#+id/app_logo"
android:layout_width="#dimen/imageViewAppLogoSize"
android:layout_height="#dimen/imageViewAppLogoSize"
android:layout_marginTop="4dp"
android:contentDescription="#string/my_app_logo"
android:src="#drawable/my_app_logo_144"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/email_field_layout"
style="#style/Widget.MyApp.TextInputLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:errorEnabled="true"
app:layout_constraintTop_toBottomOf="#+id/app_logo"
>
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/email_field"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/email"
android:inputType="textEmailAddress"
android:maxLines="1"
android:singleLine="true"
/>
</com.google.android.material.textfield.TextInputLayout>
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/password_field_layout"
style="#style/Widget.MyApp.TextInputLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:errorEnabled="true"
app:layout_constraintTop_toBottomOf="#+id/email_field_layout"
app:passwordToggleEnabled="true"
>
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/password_field"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/password"
android:imeActionId="6"
android:imeActionLabel="#string/common_signin_button_text"
android:imeOptions="actionUnspecified"
android:inputType="textPassword"
android:maxLines="1"
android:singleLine="true"
/>
</com.google.android.material.textfield.TextInputLayout>
<com.google.android.material.button.MaterialButton
android:id="#+id/login_button"
style="#style/Widget.MyApp.ContainedButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/log_in"
android:onClick="#{() -> loginViewModel.onLoginButtonClicked(emailField.text, passwordField.text)}"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/password_field_layout"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="13dp"
android:text="#string/sign_up_using_these_colon"
android:textAlignment="center"
app:layout_constraintBottom_toTopOf="#+id/signup_button_container"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
<LinearLayout
android:id="#+id/signup_button_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="13dp"
android:gravity="center"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
>
<androidx.appcompat.widget.AppCompatImageButton
android:id="#+id/email_signup_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="6.5dp"
android:background="#drawable/round_button_background"
android:src="#drawable/ic_email_24dp"
/>
<androidx.appcompat.widget.AppCompatImageButton
android:id="#+id/google_signup_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="6.5dp"
android:background="#drawable/round_button_background"
android:src="#drawable/ic_google_favicon_24dp"
/>
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
The corresponding ViewModel:
package com.aresid.myapp.login
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import timber.log.Timber
/**
* Created on: 27/04/2020
* For Project: MyApp
* Author: René Spies
* Copyright: © 2020 ARES ID
*/
class LoginViewModel: ViewModel() {
// LiveData for the login email
private val _email = MutableLiveData<String>()
val email: LiveData<String>
get() = _email
// LiveData for the login password
private val _password = MutableLiveData<String>()
val password: LiveData<String>
get() = _password
// LiveData for the login button
private val _wantLogin = MutableLiveData<Boolean>()
val wantLogin: LiveData<Boolean>
get() = _wantLogin
init {
Timber.d("init: called")
// TODO: init: init objects here
// Init email LiveData
_email.value = ""
// Init password LiveData
_password.value = ""
// Init wantLogin LiveData
_wantLogin.value = false
}
fun onLoginButtonClicked(email: String, password: String) {
Timber.d("onLoginButtonClicked: called")
Timber.d("email = $email\npassword = $password")
// TODO: onLoginButtonClicked: log in user
}
}
And the Fragments onCreateView():
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
Timber.d("onCreateView: called")
// Define LoginViewModel
loginViewModel = ViewModelProvider(this).get(LoginViewModel::class.java)
// Define FragmentLoginBinding and inflate the layout
binding = FragmentLoginBinding.inflate(inflater, container, false)
// TODO: onCreateView: code goes here
// Let the data binder know about the LoginViewModel
binding.loginViewModel = loginViewModel
// Return the inflated layout
return binding.root
}

Try this:
Use Two-way Databinding for your e-mail and password. By this your ViewModel fields will change automatically after user changes them in UI:
android:text="#={viewmodel.password}"
Your function "onLoginButtonClicked" can now be declared without parameters (these values are hold now as fields of ViewModel so you can get them freely inside function).
In your xml change the onClick as well:
android:onClick="#{() -> loginViewModel.onLoginButtonClicked()}"

LinearLayout Add multiple items

I faced a strange problem : I can't add more than one object dynamically on a LinearLayout , if they were already things , that works, So That can display multiple views
I tried with different views , there is only problems when i try to push one after the other
(there is two buttons in index 0 and 1 to test for multiple objects on the layout)
CODE :
val view = layoutInflater.inflate(R.layout.sensor_item, container, false)
val view2 = layoutInflater.inflate(R.layout.nosensor_item, container, false)
val insertPoint = viewOfLayout.findViewById(R.id.box_Parent) as LinearLayout
insertPoint.addView(view, 2)
//insertPoint.addView(view2, 3) //works
This Works too :
//insertPoint.addView(view, 3)
insertPoint.addView(view2, 2) //works
This doesn't works :
insertPoint.addView(view, 2)
insertPoint.addView(view2, 3) //doesn't works
Full Code (fragments.kt):
package com.corrupted.radheat.TEMPER
import android.os.Bundle
import android.support.v4.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.*
import kotlinx.android.synthetic.main.sensor_item.view.*
class EditFragment : Fragment() {
lateinit var option : Spinner
lateinit var result : TextView
private lateinit var viewOfLayout: View
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
viewOfLayout = inflater.inflate(R.layout.edit_fragment, container, false)
//create a view to inflate the layout_item (the xml with the textView created before)
val view = layoutInflater.inflate(R.layout.sensor_item, container, false)
val view2 = layoutInflater.inflate(R.layout.nosensor_item, container, false)
val insertPoint = viewOfLayout.findViewById(R.id.box_Parent) as LinearLayout
insertPoint.addView(view, 2)
insertPoint.addView(view2, 3)
option = view.spinner as Spinner
result = view.textView7 as TextView
val options = arrayOf("A","V")
option.adapter = ArrayAdapter<String>(activity,android.R.layout.simple_list_item_1,options)
option.onItemSelectedListener = object : AdapterView.OnItemSelectedListener{
override fun onNothingSelected(parent: AdapterView<*>?) {
result.text = "0"
}
override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
result.text = options[position]
}
}
return viewOfLayout
}
class InfoFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.info_fragment, container, false)
}
}
class ParamsFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.parameters_fragment, container, false)
}
}
Code of the fragment :
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
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/scrollView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:id="#+id/box_Parent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="#+id/button3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button" />
<Button
android:id="#+id/button4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button" />
</LinearLayout>
Code of the added view :
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:fillViewport="true"
android:id="#+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent">
<android.support.constraint.ConstraintLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="12dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="12dp"
android:background="#color/background_Item_light"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="#+id/textView9"
android:layout_width="wrap_content"
android:layout_height="24dp"
android:text=".0 C°"
android:textColor="#color/Text_Color_Light"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/textView8"
app:layout_constraintStart_toEndOf="#+id/textView8"
app:layout_constraintTop_toTopOf="#+id/textView8"
app:layout_constraintVertical_bias="0.625" />
<TextView
android:id="#+id/textView7"
android:layout_width="wrap_content"
android:layout_height="24dp"
android:layout_marginStart="4dp"
android:text=".0 C°"
android:textColor="#color/Text_Color_Light"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/textView5"
app:layout_constraintStart_toEndOf="#+id/textView5"
app:layout_constraintTop_toTopOf="#+id/textView5"
app:layout_constraintVertical_bias="0.79" />
<TextView
android:id="#+id/textView8"
android:layout_width="wrap_content"
android:layout_height="56dp"
android:layout_marginStart="10dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:text="00"
android:textColor="#color/Text_Color_Light"
android:textSize="36sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="#+id/imageButton"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.937" />
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="4dp"
android:layout_marginTop="4dp"
android:text="#string/ROOMtext"
android:textColor="#color/Text_Color_Light"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Spinner
android:id="#+id/spinner"
android:layout_width="45dp"
android:layout_height="43dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="24dp"
android:layout_marginBottom="8dp"
android:background="#color/UI_ITEM_OVERLAP_LIGHT"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/imageButton"
android:layout_width="40dp"
android:layout_height="36dp"
android:layout_marginStart="8dp"
android:layout_marginTop="6dp"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.4"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_keyboard_arrow_up_black_24dp" />
<ImageButton
android:id="#+id/imageButton3"
android:layout_width="40dp"
android:layout_height="36dp"
android:layout_marginStart="8dp"
android:layout_marginTop="2dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="6dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.4"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageButton"
app:srcCompat="#drawable/ic_keyboard_arrow_down_black_24dp" />
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="24dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:text="00"
android:textColor="#color/Text_Color_Light"
android:textSize="36sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.652" />
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
MainActivity.kt :
package com.corrupted.radheat.TEMPER
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.support.design.widget.BottomNavigationView
import android.support.v4.app.Fragment
import android.widget.*
class MainActivity : AppCompatActivity() {
private val fragmentManager = supportFragmentManager
private val fragmentTransaction = fragmentManager.beginTransaction()
private val editfragment = EditFragment()
private val infofragment = InfoFragment()
private val parametersfragment = ParamsFragment()
private fun showFragment(fragment: Fragment) {
val fragmentManager = supportFragmentManager
fragmentManager.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit()
}
private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.action_edit -> {
showFragment(editfragment)
return#OnNavigationItemSelectedListener true
}
R.id.action_info-> {
showFragment(infofragment)
return#OnNavigationItemSelectedListener true
}
R.id.action_Settings-> {
showFragment(parametersfragment)
return#OnNavigationItemSelectedListener true
}
}
false
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
fragmentTransaction.add(R.id.fragment_container, infofragment)
fragmentTransaction.commit()
setContentView(R.layout.activity_main)
val navigation = findViewById<BottomNavigationView>(R.id.activity_main_bottom_navigation)
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener)
// Create a GLSurfaceView instance and set it
// as the ContentView for this Activity.
}
}
Pic of it working : https://imgur.com/gallery/mLb4G5b
Thanks

Android LinearLayout Gone don't update automatically

I have a form that it could be submitted and send the data to an API, so when I receive the callback of request done I would like to hide the form and show a view of thanks.
This is my layout :
<?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:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"
android:animateLayoutChanges="true">
<LinearLayout
android:id="#+id/thank_you_layout_rate"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:visibility="gone"
tools:ignore="UseCompoundDrawables">
<ImageView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_marginTop="20dp"
android:src="#drawable/ic_check_circle_green_800_48dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_marginTop="5dp"
android:fontFamily="#font/roboto_medium"
android:gravity="center"
android:text="#string/thank_you_for_rating"
android:textAppearance="#android:style/TextAppearance.Material.Large"
android:textColor="#color/DarkBlue"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:id="#+id/form_rating"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:visibility="visible">
<TextView
android:id="#+id/textView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="5dp"
android:layout_weight="0.1"
android:fontFamily="#font/roboto_medium"
android:gravity="center"
android:text="#string/rate_our_app"
android:textAppearance="#android:style/TextAppearance.Material.Large"
android:textColor="#color/DarkBlue"
android:textStyle="bold" />
<RatingBar
android:id="#+id/ratingbar_rate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="5dp"
android:isIndicator="false"
android:numStars="5"
android:rating="4"
android:stepSize="1" />
<View
android:id="#+id/divider"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="10dp"
android:background="?android:attr/listDivider" />
<EditText
android:hint="#string/rate_our_app"
android:id="#+id/comment_rate"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.8"
android:inputType="textMultiLine"
android:textAppearance="#android:style/TextAppearance.Material.Large"
android:textColor="#color/DarkBlue"
/>
<Button
android:id="#+id/save_rate"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginEnd="30dp"
android:layout_marginStart="30dp"
android:layout_marginTop="10dp"
android:layout_marginBottom="15dp"
android:layout_weight="0.1"
android:background="#color/DecathlonBlue"
android:fontFamily="#font/roboto_medium"
android:gravity="center"
android:text="#string/save"
android:textAlignment="center"
android:textAppearance="#android:style/TextAppearance.Material.Large"
android:textColor="#color/LightGrey"
android:textAllCaps="true"/>
</LinearLayout>
</LinearLayout>
and this is my fragment :
class RateFragment : Fragment(), RateFragmentListener {
private lateinit var mLoginManager: LoginManager
private lateinit var loadingDialog: LoadingDialog
private lateinit var ratePresenter: RatePresenter
private lateinit var mView: View
private lateinit var rateNotAllowed: LinearLayout
private lateinit var formRating: LinearLayout
companion object {
fun newInstance(loginManager: LoginManager): Fragment {
val currentFragment = RateFragment()
currentFragment.mLoginManager = loginManager
return currentFragment
}
}
override fun onResume() {
this.stopLoadingDialog()
super.onResume()
}
/**
*
* #param inflater LayoutInflater
* #param container ViewGroup?
* #param savedInstanceState Bundle?
* #return View?
*/
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
mView = inflater.inflate(R.layout.rate_fragment, container, false)
val saveButton = mView.findViewById<Button>(R.id.save_rate)
val starBar = mView.findViewById<RatingBar>(R.id.ratingbar_rate)
val commentRate = mView.findViewById<EditText>(R.id.comment_rate)
rateNotAllowed = mView.findViewById(R.id.thank_you_layout_rate)
formRating = mView.findViewById(R.id.form_rating)
loadingDialog = LoadingDialog(context!!)
startLoadingDialog()
initPresenter(activity as Activity, this)
saveButton.setOnClickListener {
this.startLoadingDialog()
ratePresenter.sendRating(
commentRate.text.toString(),
starBar.rating
)
}
return mView
}
/**
*
* #param activity Activity
*/
private fun initPresenter(
activity: Activity,
rateFragment: RateFragment
) {
ratePresenter = RatePresenter(activity, mLoginManager, rateFragment)
}
/**
* Loading dialog, block the UI
*/
override fun stopLoadingDialog() {
loadingDialog.dismiss()
}
/**
* Loading dialog, block de UI
*/
override fun startLoadingDialog() {
loadingDialog.show()
}
override fun rateSent() {
stopLoadingDialog()
}
override fun rateError() {
activity!!.toast("error on sending the rating")
stopLoadingDialog()
}
override fun rateNotAllowed() {
formRating.visibility = View.GONE
rateNotAllowed.visibility = View.VISIBLE
}
}
But the update of the view isn't done automatically only if I change the vie and come back to it ( there is an if inside the presenter that check if a note is sent or not ).
Thank you, regards