I read a few posts to convert from String to Integer and tried to do the same to convert string to double using two-way binding but was unable to do it.
SampleViewModel.kt
class SampleViewModel: ViewModel() {
val weight = MutableLiveData<Double>()
fun validateFields() {
Log.i("SAMPLE_VIEW_MODEL", "validateFields: ${weight.value}")
}
}
TypeConverters.kt
object TypeConverters {
#InverseMethod("stringToDouble")
#JvmStatic
fun doubleToString(value: Double?): String {
return value?.toString() ?: ""
}
#JvmStatic
fun stringToDouble(value: String): Double? {
if (TextUtils.isEmpty(value)) {
return null
}
return value.toDoubleOrNull()
}
}
fragment_sample.xml
<?xml version="1.0" encoding="utf-8"?>
<layout>
<data>
<variable
name="viewModel"
type="com.example.sampleapp.SampleViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
...
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/til_weight"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="#dimen/_10sdp"
android:hint="#string/hint_weight"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="#+id/tilName">
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/tiet_weight"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:text="#={TypeConverters.doubleToString(viewModel.weight)}"/>
</com.google.android.material.textfield.TextInputLayout>
...
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
The example above does not let me enter the proper value on UI like "56.78". I tried to follow this post but doesn't work for me. Another way is to take string value and then convert it into double and vice versa accordingly. I would like to know which is the correct way.
In your TextInputEditText, update this line
android:text="#={String.valueOf(viewModel.weight)}"
See Results
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/tiet_weight"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:text="#={String.valueOf(viewModel.weight)}"/>
I'm learning data binding, the following code is from the project.
The android:text in plain_activity_solution_3.xml bind to SimpleViewModel with name which is String.
The android:text in solution.xml bind to SimpleViewModelSolution with name which is LiveData<String>.
Why can either String or LiveData<string> be bind to android:text? In my mind , only one is allowed to be bind to android:text.
SimpleViewModel.kt
class SimpleViewModel : ViewModel() {
val name = "Grace"
val lastName = "Hopper"
var likes = 0
private set // This is to prevent external modification of the variable.
...
}
plain_activity_solution_3.xml
<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="viewmodel"
type="com.example.android.databinding.basicsample.data.SimpleViewModel"/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/plain_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="128dp"
android:text="#{viewmodel.name}"
...
}
SimpleViewModelSolution.kt
class SimpleViewModelSolution : ViewModel() {
private val _name = MutableLiveData("Ada")
private val _lastName = MutableLiveData("Lovelace")
private val _likes = MutableLiveData(0)
val name: LiveData<String> = _name
val lastName: LiveData<String> = _lastName
val likes: LiveData<Int> = _likes
...
}
solution.xml
<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="viewmodel"
type="com.example.android.databinding.basicsample.data.SimpleViewModelSolution"/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- A simple binding between a TextView and a string observable in the ViewModel -->
<TextView
android:id="#+id/name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="128dp"
android:text="#{viewmodel.name}"
...
}
As the document says:
Any plain-old object can be used for data binding, but modifying the object doesn't automatically cause the UI to update. Data binding can be used to give your data objects the ability to notify other objects, known as listeners, when its data changes.
LiveData<string> is observable, too.
This is by design, and discussed in documentation. The binder will accept either the native data type, or something that's "Observable", like LiveData. If an observable object is provided, the binder will subscribe to the object's changes and bind those to the view, saving you lines of code.
I am building an Android app.
I have a layout that contains a button 'saveButton'. When the user clicks the button, the onClick should call a function in my ViewModel, onSave(). This function requires 2 parameters: the text contents of 2 EditText views that are also present in the same layout.
Basically, the user has edited the name and/or the synopsis and now wants to have the ViewModel update the object's data in the database.
(Part of) my UI (.xml fragment layout):
<?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"
tools:context=".ui.CreateEditRelationFragment">
<data>
<variable
name="createEditRelationViewModel"
type="be.pjvandamme.farfiled.viewmodels.CreateEditRelationViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/saveButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/saveText"
android:onClick="#{() -> createEditRelationViewModel.onSave(relationNameEditText.getEditText().getText().toString(), relationSynopsisEditText.getEditText().getText().toString())}" />
<Button
android:id="#+id/cancelButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="32dp"
android:text="#string/cancelText"
android:onClick="#{() -> createEditRelationViewModel.onCancel()}" />
<EditText
android:id="#+id/relationSynopsisEditText"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:ems="10"
android:gravity="start|top"
android:inputType="textMultiLine" />
<EditText
android:id="#+id/relationNameEditText"
android:layout_width="#dimen/relationNameEditWidth"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="16dp"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
</androidx.constraintlayout.widget.ConstraintLayout>
(Part of) the ViewModel:
class CreateEditRelationViewModel (
private val relationKey: Long?,
val database: RelationDao,
application: Application
): AndroidViewModel(application){
private var viewModelJob = Job()
private val uiScope = CoroutineScope(Dispatchers.Main + viewModelJob)
private var relation = MutableLiveData<Relation?>()
private var _navigateToRelationDetail = MutableLiveData<Boolean>()
val navigateToRelationDetail: LiveData<Boolean>
get() = _navigateToRelationDetail
fun onSave(name: String, synopsis: String){
Timber.i("Got name: " + name + " and synopsis: " + synopsis)
if(relationKey == null){
uiScope.launch{
relation.value = Relation(0, name, synopsis, false)
insert(relation.value!!)
}
}
else{
uiScope.launch{
relation.value?.name = name
relation.value?.synopsis = synopsis
update(relation.value)
}
}
_navigateToRelationDetail.value = true
}
private suspend fun insert(newRelation: Relation){
withContext(Dispatchers.IO){
database.insert(newRelation)
}
}
private suspend fun update(relation: Relation?){
if(relation != null) {
withContext(Dispatchers.IO) {
database.update(relation)
}
}
}
}
I would want this thing to compile so that the onSave() function is called and the contents of the EditTexts passed as parameters.
I cannot manage to pass the text contents of these EditTexts. The compiler throws this error:
[databinding] {"msg":"cannot find method getEditText() in class android.widget.EditText","file":"D:\\ etc.
It does the same thing when I try to access using the .text property directly.
Does anyone know what I'm doing wrong? I'm tearing my hair out.
getEditText() method doesn't exist and you can remove it.
instead of;
relationNameEditText.getEditText().getText().toString()
you can do
relationNameEditText.getText().toString()`
i.e.
https://github.com/dgngulcan/droid-feed/blob/e0d0d5f4af07c5375d42b74e42c55b793319a937/app/src/main/res/layout/fragment_newsletter.xml#L120
What is the best approach to validate form data using ViewModel and Databinding?
I have a simple Sign-Up activity that links binding layout and ViewModel
class StartActivity : AppCompatActivity() {
private lateinit var binding: StartActivityBinding
private lateinit var viewModel: SignUpViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
viewModel = ViewModelProviders.of(this, SignUpViewModelFactory(AuthFirebase()))
.get(SignUpViewModel::class.java);
binding = DataBindingUtil.setContentView(this, R.layout.start_activity)
binding.viewModel = viewModel;
signUpButton.setOnClickListener {
}
}
}
ViewModel with 4 ObservableFields and signUp() method that should validate data before submitting data to the server.
class SignUpViewModel(val auth: Auth) : ViewModel() {
val name: MutableLiveData<String> = MutableLiveData()
val email: MutableLiveData<String> = MutableLiveData()
val password: MutableLiveData<String> = MutableLiveData()
val passwordConfirm: MutableLiveData<String> = MutableLiveData()
fun signUp() {
auth.createUser(email.value!!, password.value!!)
}
}
I guess we can add four boolean ObservableFields for each input, and in signUp() we can check inputs and change state of boolean ObservableField that will produce an appearing error on layout
val isNameError: ObservableField<Boolean> = ObservableField()
fun signUp() {
if (name.value == null || name.value!!.length < 2 ) {
isNameError.set(true)
}
auth.createUser(email.value!!, password.value!!)
}
But I am not sure that ViewModel should be responsible for validation and showing an error for a user and we will have boilerplate code
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<import type="android.view.View" />
<variable
name="viewModel"
type="com.maximdrobonoh.fitnessx.SignUpViewModel" />
</data>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorGreyDark"
android:orientation="vertical"
android:padding="24dp">
<TextView
android:id="#+id/appTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="#string/app_title"
android:textColor="#color/colorWhite"
android:textSize="12sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<LinearLayout
android:id="#+id/screenTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:orientation="horizontal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/appTitle">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="4dp"
android:text="#string/sign"
android:textColor="#color/colorWhite"
android:textSize="26sp"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/up"
android:textColor="#color/colorWhite"
android:textSize="26sp" />
</LinearLayout>
<LinearLayout
android:id="#+id/form"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:orientation="vertical"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/screenTitle">
<android.support.v7.widget.AppCompatEditText
style="#style/SignUp.InputBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/sign_up_name"
android:inputType="textPersonName"
android:text="#={viewModel.name}" />
<android.support.v7.widget.AppCompatEditText
style="#style/SignUp.InputBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/sign_up_email"
android:inputType="textEmailAddress"
android:text="#={viewModel.email}"
/>
<android.support.v7.widget.AppCompatEditText
style="#style/SignUp.InputBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/sign_up_password"
android:inputType="textPassword"
android:text="#={viewModel.password}" />
<android.support.v7.widget.AppCompatEditText
style="#style/SignUp.InputBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/sign_up_confirm_password"
android:inputType="textPassword"
android:text="#={viewModel.passwordConfirm}" />
<Button
android:id="#+id/signUpButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:background="#drawable/button_gradient"
android:text="#string/sign_up_next_btn"
android:textAllCaps="true"
android:textColor="#color/colorBlack" />
</LinearLayout>
</android.support.constraint.ConstraintLayout>
</layout>
There can be many ways to implement this. I am telling you two solutions, both works well, you can use which you find suitable for you.
I use extends BaseObservable because I find that easy than converting all fields to Observers. You can use ObservableFields too.
Solution 1 (Using custom BindingAdapter)
In xml
<variable
name="model"
type="sample.data.Model"/>
<EditText
passwordValidator="#{model.password}"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#={model.password}"/>
Model.java
public class Model extends BaseObservable {
private String password;
#Bindable
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
notifyPropertyChanged(BR.password);
}
}
DataBindingAdapter.java
public class DataBindingAdapter {
#BindingAdapter("passwordValidator")
public static void passwordValidator(EditText editText, String password) {
// ignore infinite loops
int minimumLength = 5;
if (TextUtils.isEmpty(password)) {
editText.setError(null);
return;
}
if (editText.getText().toString().length() < minimumLength) {
editText.setError("Password must be minimum " + minimumLength + " length");
} else editText.setError(null);
}
}
Solution 2 (Using custom afterTextChanged)
In xml
<variable
name="model"
type="com.innovanathinklabs.sample.data.Model"/>
<variable
name="handler"
type="sample.activities.MainActivityHandler"/>
<EditText
android:id="#+id/etPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:afterTextChanged="#{(edible)->handler.passwordValidator(edible)}"
android:text="#={model.password}"/>
MainActivityHandler.java
public class MainActivityHandler {
ActivityMainBinding binding;
public void setBinding(ActivityMainBinding binding) {
this.binding = binding;
}
public void passwordValidator(Editable editable) {
if (binding.etPassword == null) return;
int minimumLength = 5;
if (!TextUtils.isEmpty(editable.toString()) && editable.length() < minimumLength) {
binding.etPassword.setError("Password must be minimum " + minimumLength + " length");
} else {
binding.etPassword.setError(null);
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
ActivityMainBinding binding;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.setModel(new Model());
MainActivityHandler handler = new MainActivityHandler();
handler.setBinding(binding);
binding.setHandler(handler);
}
}
Update
You can also replace
android:afterTextChanged="#{(edible)->handler.passwordValidator(edible)}"
with
android:afterTextChanged="#{handler::passwordValidator}"
Because parameter are same of android:afterTextChanged and passwordValidator.
This approach uses TextInputLayouts, a custom binding adapter, and creates an enum for form errors. The result I think reads nicely in the xml, and keeps all validation logic inside the ViewModel.
The ViewModel:
class SignUpViewModel() : ViewModel() {
val name: MutableLiveData<String> = MutableLiveData()
// the rest of your fields as normal
val formErrors = ObservableArrayList<FormErrors>()
fun isFormValid(): Boolean {
formErrors.clear()
if (name.value?.isNullOrEmpty()) {
formErrors.add(FormErrors.MISSING_NAME)
}
// all the other validation you require
return formErrors.isEmpty()
}
fun signUp() {
auth.createUser(email.value!!, password.value!!)
}
enum class FormErrors {
MISSING_NAME,
INVALID_EMAIL,
INVALID_PASSWORD,
PASSWORDS_NOT_MATCHING,
}
}
The BindingAdapter:
#BindingAdapter("app:errorText")
fun setErrorMessage(view: TextInputLayout, errorMessage: String) {
view.error = errorMessage
}
The XML:
<layout>
<data>
<import type="com.example.SignUpViewModel.FormErrors" />
<variable
name="viewModel"
type="com.example.SignUpViewModel" />
</data>
<!-- The rest of your layout file etc. -->
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/text_input_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:errorText='#{viewModel.formErrors.contains(FormErrors.MISSING_NAME) ? "Required" : ""}'>
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:text="#={viewModel.name}"/>
</com.google.android.material.textfield.TextInputLayout>
<!-- Any other fields as above format -->
And then, the ViewModel can be called from activity/fragment as below:
class YourActivity: AppCompatActivity() {
val viewModel: SignUpViewModel
// rest of class
fun onFormSubmit() {
if (viewModel.isFormValid()) {
viewModel.signUp()
// the rest of your logic to proceed to next screen etc.
}
// no need for else block if form invalid, as ViewModel, Observables
// and databinding will take care of the UI
}
}
I've written a library for validating bindable fields of an Observable object.
Setup your Observable model:
class RegisterUser:BaseObservable(){
#Bindable
var name:String?=""
set(value) {
field = value
notifyPropertyChanged(BR.name)
}
#Bindable
var email:String?=""
set(value) {
field = value
notifyPropertyChanged(BR.email)
}
}
Instantiate and add rules
class RegisterViewModel : ViewModel() {
var user:LiveData<RegisterUser> = MutableLiveData<RegisterUser>().also {
it.value = RegisterUser()
}
var validator = ObservableValidator(user.value!!, BR::class.java).apply {
addRule("name", ValidationFlags.FIELD_REQUIRED, "Enter your name")
addRule("email", ValidationFlags.FIELD_REQUIRED, "Enter your email")
addRule("email", ValidationFlags.FIELD_EMAIL, "Enter a valid email")
addRule("age", ValidationFlags.FIELD_REQUIRED, "Enter your age (Underage or too old?)")
addRule("age", ValidationFlags.FIELD_MIN, "You can't be underage!", limit = 18)
addRule("age", ValidationFlags.FIELD_MAX, "You sure you're still alive?", limit = 100)
addRule("password", ValidationFlags.FIELD_REQUIRED, "Enter your password")
addRule("passwordConfirmation", ValidationFlags.FIELD_REQUIRED, "Enter password confirmation")
addRule("passwordConfirmation", ValidationFlags.FIELD_MATCH, "Passwords don't match", "password")
}
}
And setup your xml file:
<com.google.android.material.textfield.TextInputLayout
style="#style/textFieldOutlined"
error='#{viewModel.validator.getValidation("email")}'
android:layout_width="match_parent"
android:layout_height="wrap_content">
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/email"
style="#style/myEditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Your email"
android:imeOptions="actionNext"
android:inputType="textEmailAddress"
android:text="#={viewModel.user.email}" />
What you have in mind is right, actually. The viewmodel should not know anything about the android system and will only work with pure java/kotlin. Thus, doing what you are thinking of is right. ViewModel's shouldn't know about the android system as all view interactions should be handled on the View. But, their properties can be bounded to the view.
TL;DR
This will work
fun signUp() {
if (name.value == null || name.value!!.length < 2 ) {
isNameError.set(true)
}
auth.createUser(email.value!!, password.value!!)
}
Suggestion
I would suggest, if you would like to dig in deeper, you could use Custom Binding Adapters. This way you:
won't need additional variables to your view model
have a cleaner view model since the error handling is on the custom binding adapter
would easier read on your XML views as you could define there the validations you need
I'll let your imagination fly on how you could make the custom binding adapter only have the validations. For now, it's better to understand the basics of custom binding adapters.
Cheers
Yes, you can use your validation logic from ViewModel, because you're having your observable variables from ViewModel & your xml is also deriving data from ViewModel class also.
So, Solution :
You can create #BindingAdapter in ViewModel and bind your
button click with it. Check your validation there and do some other
stuffs also.
You can create Listener, and implement it on ViewModel to receive clicks from button and bind that listener to xml.
You can use Two-Way data binding also (Be aware of infinite loops though).
//Let's say it's your binding adapter from ViewModel
fun signUp() {
if (check validation logic) {
// Produce errors
}
// Further successful stuffs
}
I have the standard login form which has 2 edit text (one for email and other for password) and a button for log-in.
I want to send email and password to the server when the user clicks on login button.
activity_main.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">
<data class="ActivityMainBinding">
<variable
name="login"
type="com.example.itstym.reminder.loginViewModel" />
<variable
name="handler"
type="com.example.itstym.reminder.LoginHandler" />
</data>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.itstym.reminder.MainActivity">
<EditText
app:error="#{login.errorEmail}"
android:text="#{login.userEmailAddress}"
android:hint="Email Address"
android:id="#+id/email_address"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="24dp"/>
<EditText
app:error="#{login.errorPassword}"
android:text="#{login.userPassword}"
android:hint="Password"
android:id="#+id/user_password"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="0dp"
android:ems="10"
android:inputType="textPassword"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="#+id/email_address"
android:layout_marginTop="16dp"
app:layout_constraintTop_toBottomOf="#+id/email_address"/>
<Button
android:onClick="#{() -> handler.onLoginButtonClicked(login)}"
android:id="#+id/submit_button"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="24dp"
android:text="Sign In"
app:layout_constraintEnd_toEndOf="#+id/user_password"
app:layout_constraintStart_toStartOf="#+id/user_password"
app:layout_constraintTop_toBottomOf="#+id/user_password"/>
</android.support.constraint.ConstraintLayout>
</layout>
MainActivity.kt
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val binding=DataBindingUtil.setContentView<com.example.itstym.reminder.databinding.ActivityMainBinding>(this#MainActivity,R.layout.activity_main)
Log.i("Binding class ",binding.javaClass.simpleName.toString())
Log.i("type ",binding.javaClass.toString())
val login:loginViewModel=loginViewModel()
binding.login=login
val handler= LoginHandler()
binding.handler=handler
}
}
loginViewModel.kt
class loginViewModel(): BaseObservable() {
#Bindable
var userEmailAddress:String= String()
set(userEmailAddress){
field=userEmailAddress
notifyPropertyChanged(R.id.email_address)
/*to check Email for validation on every character inserted by user*/
notifyPropertyChanged(BR.errorEmail)
}
get() {
return field
}
#Bindable
var userPassword:String = String()
set(userPassword){
field=userPassword
notifyPropertyChanged(R.id.user_password)
notifyPropertyChanged(BR.errorPassword)
}
get() {
return field
}
}
//some code removed for readablitly purpose
LoginHandler.kt
class LoginHandler() {
fun onLoginButtonClicked(userInfo: loginViewModel){
Log.i("Button Clicked ","yup")
Log.i("Email is ",userInfo.userEmailAddress)
Log.i("Password is ",userInfo.userPassword)
}
}
Problem: I am not able to print the email address and password inside the written in onLoginButtonClicked(). Why??
Any lead will helpfull.
Before downvoting the question, add the comment that will helps in improving the question.
In your activity_main.xml file, you're only using One-Way Data Binding. If you want to use Two-Way Data Binding, you must use the equal sign after the at sign (#=) for example:
One-way Data Binding (Only update the view when the property change)
android:text="#{login.userEmailAddress}"
android:text="#{login.userPassword}"
Two-way Data Binding (Update the view when the property change and vice-versa)
android:text="#={login.userEmailAddress}"
android:text="#={login.userPassword}"
There is a great talk about Data Binding by Kevin Pelgrim if you want to go deeper with the topic.
Extra Resources:
Episode 057: Data Binding with GDE Lisa Wray - Fragmented Podcast
Episode 35: Data Bound - Android Developer Backstage
Hope it helps!