如何在viewModel中使用双向绑定

Question

我的片段中有一个EditText，我想将EditText的文本值与viewModel的变量双向绑定，这样我就可以在viewModel中获得这个文本值来做一些额外的工作。

视图模型：

class MyViewModel @ViewModelInject constructor(
private val myRepository: MyRepository,
private val myPreferences: MyPreferences
) : ViewModel() {
val name = myPreferences.getStoredName()
fun buttonSubmit() {
viewModelScope.launch(Dispatchers.IO) {
myPreferences.setStoredName(name)
val response = myRepository.doSomething(name)  // I can get the text value by name variable
}
}

xml:

<layout ...>
<data>
<variable
name="viewModel"
type=".MyViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
...>
<EditText
...
android:text="@={viewModel.name}" />  <!-- how to two-way binding name -->
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

Answer 1

您只需要将name定义为MutableLiveData。因此，EditText的所有文本更改都会反映到它上，您将能够读取buttonSubmit中的值，如下所示：(您的xml内容是正确的(

class MyViewModel @ViewModelInject constructor(
private val myRepository: MyRepository,
private val myPreferences: MyPreferences
) : ViewModel() {
val name = MutableLiveData(myPreferences.getStoredName())
fun buttonSubmit() {
viewModelScope.launch(Dispatchers.IO) {
myPreferences.setStoredName(name.value ?: "")
val response = myRepository.doSomething(name.value ?: "")
}
}
}