Use Done button on Keyboard in Databinding

Question

I am trying to use the done button of the soft keyboard to activate a method via databinding. Just like onClick. Is there a way to do that?

example:

<EditText               
    android:id="@+id/preSignUpPg2EnterPhone"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"       
    onOkInSoftKeyboard="@{(v) -> viewModel.someMethod()}"
    />

onOkInSoftKeyboard doesn't exists... Is there something to create this behavior?

Thanks!

Answer 1

I won't claim to be an expert in onEditorAction() or soft keyboard. That said, assuming you use the solution to the stack overflow question Firoz Memon suggested, you can make it happen. Even if there is another solution that works better, this can give you an idea on how to add your own event handlers.

You'd need a binding adapter that takes some kind of handler. Let's assume you have an empty listener like this:

public class OnOkInSoftKeyboardListener {
    void onOkInSoftKeyboard();
}

Then you need a BindingAdapter:

@BindingAdapter("onOkInSoftKeyboard") // I like it to match the listener method name
public static void setOnOkInSoftKeyboardListener(TextView view,
        final OnOkInSoftKeyboardListener listener) {
    if (listener == null) {
        view.setOnEditorActionListener(null);
    } else {
        view.setOnEditorActionListener(new OnEditorActionListener() {
            @Override
            public void onEditorAction(TextView v, int actionId, KeyEvent event) {
                // ... solution to receiving event
                if (somethingOrOther) {
                    listener.onOkInSoftKeyboard();
                }
            }
        });
    }
}

Answer 2

Using Kotlin, kapt produces:

e: [kapt] An exception occurred: android.databinding.tool.util.LoggedErrorException: Found data binding errors.
****/ data binding error ****msg:Listener class kotlin.jvm.functions.Function1 with method invoke did not match signature of any method viewModel::signIn

(because viewModel::signIn is of type KFunction1) so we can't use a method reference. However, if we create a variable within the viewModel that is explicit about the type, then we can pass that variable as the binding's param. (or just use a class)

Bindings.kt:

@BindingAdapter("onEditorEnterAction")
fun EditText.onEditorEnterAction(f: Function1<String, Unit>?) {

    if (f == null) setOnEditorActionListener(null)
    else setOnEditorActionListener { v, actionId, event ->

        val imeAction = when (actionId) {
            EditorInfo.IME_ACTION_DONE,
            EditorInfo.IME_ACTION_SEND,
            EditorInfo.IME_ACTION_GO -> true
            else -> false
        }

        val keydownEvent = event?.keyCode == KeyEvent.KEYCODE_ENTER 
            && event.action == KeyEvent.ACTION_DOWN

        if (imeAction or keydownEvent)
            true.also { f(v.editableText.toString()) }
        else false
    }
}

MyViewModel.kt:

fun signIn(password: String) {
    Toast.makeText(context, password, Toast.LENGTH_SHORT).show()
}

val signIn: Function1<String, Unit> = this::signIn

layout.xml:

<EditText
    android:id="@+id/password"
    app:onEditorEnterAction="@{viewModel.signIn}"
    android:imeOptions="actionDone|actionSend|actionGo"
    android:singleLine="true"/>

Answer 3

Just as i was looking at this myself, here a simpler version where the function is directly called from the data binding:

In your ViewModel use this function:

 public boolean onEditorAction(TextView view, int actionId, KeyEvent event) {
return false; // if you want the default action of the actionNext or so on
return true; // if you want to intercept
}

And in the layout:

android:onEditorAction="@{(view,actionId,event) -> viewModel.onEditorAction(view,actionId,event)}"

Answer 4

Kotlin, without writing custom binding adapter

In Layout,

<EditText
    ...
    android:onEditorAction="@{(view, actionId, event) -> viewModel.onDoneClicked(view, actionId, event)}" />

ViewModel

fun onDoneClicked(view: View, actionId: Int, event: KeyEvent?): Boolean {
    if(actionId == EditorInfo.IME_ACTION_DONE) {
        // handle here
        return true
    }
    return false
}

Note: event can be null, so make KeyEvent nullable by putting ? there.

Answer 5

You can directly call login method what inside ViewModel by implementing setOnEditorActionListener to the Edittext, taking reference from binging class

loginFragmentBinding.etPassword.setOnEditorActionListener(TextView.OnEditorActionListener { _, actionId, _ ->
        if (actionId == EditorInfo.IME_ACTION_DONE) {
            loginViewModel.login()
            return@OnEditorActionListener true
        }
        false
    })

Answer 6

Android framework already have this implemented. Take a look at TextViewBindingAdapter

You'll see those attributes, the documentation kind of glosses over what this means, but in a nutshell:

• attribute = when this attribute appears in a layout file
• type = then look for the implementation in this class
• method = of a method with this name in the class defined in type

For more on this take a look at this blog post.