CODEWITHSUNDEEP
androidandroid-databinding
houman.sanati
houman.sanati

Reputation: 1074

binding onTextChanged for edit text

I am trying to bind edittext onTextChanged to the viewmodel.

this is my XML:

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>

        <variable
            name="viewmodel"
            type="mvvm.f4wzy.com.samplelogin.ui.login.viewmodel.LoginViewModel" />
    </data>

    <EditText
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:inputType="text"
        android:onTextChanged="@{viewmodel.onEmailChanged}"
        android:paddingStart="5dp"
        android:textColor="#383838"
        android:textSize="20sp"/>
</layout>

LoginViewModel.kt

class LoginViewModel(application: Application) : AndroidViewModel(application) {


    fun onEmailChanged(s: CharSequence) {
        //some code

    }

}

kapt gives me an error for on text changed and it says:

[kapt] An exception occurred: android.databinding.tool.util.LoggedErrorException: Found data binding errors. ****/ data binding error ****msg:Cannot resolve type for viewmodel.onEmailChanged

I have tried android:onTextChanged="@{(s) -> viewmodel.onEmailChanged}" and android:onTextChanged="@{viewmodel::onEmailChanged}" but still same error.

any help?

Upvotes: 1

Views: 4618

Answers (1)

Julio E. Rodr&#237;guez Caba&#241;as
Julio E. Rodr&#237;guez Caba&#241;as

Reputation: 2129

Why don't you just use two-way binding with a LiveData property?

First, add the new email property to your viewmodel and subscribe to it to receive the changes:

class LoginViewModel(application: Application) : AndroidViewModel(application) {

    val email = MutableLiveData<String>()

    // This observer will invoke onEmailChanged() when the user updates the email
    private val emailObserver = Observer<String> { onEmailChanged(it) }

    init {
        email.observeForever(emailObserver)
    }

    override fun onCleared() {
        email.removeObserver(emailObserver)
    }

    fun onEmailChanged(newEmail: String) {
        // Some code
    }
}

Then, update the view to create a two-way binding between the EditText and the property email of your viewmodel:

<EditText
    ...
    android:text="@={viewModel.email}" />

Thanks to the two-way binding, whenever the user updates the text in the view, your viewmodel property will update (and vice versa).

This should hopefully do the trick!

Upvotes: 5

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