How to make `onClick()` in xml call two methods?

Question

I want to make onClick() in my layout xml trigger two methods from two viewmodels.

Code:

<Button
    android:onClick="@{() -> model.onButtonClick()}"
    ... />

The above code calls one method, I want it to call another one in from a different viewmodel.
Function call I want to add: model2.onButtonClick()

Is it possible? If yes, kindly add an minimal example. (Expecting a xml solution)

Note: Viewmodels are passed as arguments in xml. (data-binding variables)

Edit 1: Both functions are in two different view models. So I (after some research) know that using/declaring/initializing one view model inside another is not a good practise.

I could create a click listener inside my fragment and call both functions there. But I want to eliminate click listener in fragments (views as per MVVM).

I am not looking for some possible way. I am searching for a best practise method, where I intend to implement MVVM, seperation of concerns and data-binding.

Why u won't call the second function inside first ? – Edhar Khimich Jul 14 '19 at 04:49 — Edhar Khimich, Jul 14 '19 at 04:49
@EdgarKhimich Please check the edited question. – Abhimanyu Jul 14 '19 at 04:59 — Abhimanyu, Jul 14 '19 at 04:59

score 5 · Answer 1 · answered Sep 24 '19 at 13:53

5

I've found solution. Maybe stupid but genius in the simplicity:

app:onRefreshListener="@{() -> dashboardVM.onRefresh() != homeVM.onRefresh()}"

method needs to return true/false -> no matter.

For any other number of methods use OR and return always false.

Correct solution shall be implemented via converter. But it takes a lot of code.

answered Sep 24 '19 at 13:53

user2239604

71
2
7

that's brilliant !! soo clean and obvious when you know it :) cool! – Filipkowicz Jan 26 '21 at 22:40
Wow This is really cool:) But I think it's hard to use, because there could be misunderstanding. – Isaac Lee Nov 03 '21 at 06:23

Chrisvin Jem · Answer 2 · 2019-07-14T04:59:55.810

1

You have two options,

Call the second method in the first method.

fun method1() {
//do stuff 
method2() 
} 
fun method2() {
//do more stuff
}

In case you don't want to mess up your existing code structure, Create a separate function that calls the two functions.

fun onClickMethod () {
method1() 
method2() 
} 
fun method1() {
//do stuff  
} 
fun method2() {
//do stuff
}

edited Jul 14 '19 at 04:59

answered Jul 14 '19 at 04:51

Chrisvin Jem

3,940
1
8
24

You could try to set up a basic subscriber model, wherein the viewmodels subscribe their function to be called on a button onClick. I've never done that before, but I've seen a colleague set up something similar before. Not sure if it's a good practice or not though. – Chrisvin Jem Jul 14 '19 at 05:14

score 0 · Answer 3 · answered Jul 14 '19 at 05:06

0

In your xml import two view models and pass them as params in your custom method which will call each method from the view models.

I have never try that before but it should work. Let me know if you don't understand

answered Jul 14 '19 at 05:06

Edhar Khimich

1,468
1
17
20

It does work. But it introduces coupling, which I am trying to eliminate. – Abhimanyu Jul 14 '19 at 16:56
Why you call it coupling ? It will do the logic that you will want to integrate – Edhar Khimich Jul 14 '19 at 18:53

score 0 · Answer 4 · answered Oct 22 '20 at 06:57

Using a Higher-order function we can achieve trigger two methods at the same time

  <?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">
    
        <data>
    
            <import type="android.view.View" />
    
            <variable
                name="cartViewModel"
                type="com.rizek.android.users.ui.cart.CartViewModel" />
    
            <variable
                name="product"
                type="com.rizek.android.users.model.productlist.Product" />
    
            <variable
                name="productInteractionListener"
                type="com.rizek.android.users.adapters.recyclerview.cart.ProductListAdapter.ProductInteractionListener" />
        </data>
    
        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">
    
            <TextView
                style="@style/text_medium"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:drawablePadding="8dp"
                android:onClick="@{()->
                productInteractionListener.onItemStateChanged(product,cartViewModel.addProduct(product))
                }"
                android:padding="8dp"
                android:text="Add to basket"
                android:textColor="@color/blue"
                android:textSize="14sp"
                app:drawableStartCompat="@drawable/ic_add_circle"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />
    
        </androidx.constraintlayout.widget.ConstraintLayout>
    </layout>

ProductInteractionListener

interface ProductInteractionListener {
           fun onItemStateChanged(product: Product, action: () -> Unit)
        }

score 0 · Answer 5 · answered Mar 17 '22 at 16:20

0

This work for me:

<Button
    android:onClick="@{() -> model.onButtonClick() ? model2.onButtonClick() : void}"
    ... />

In fun onButtonClick() you must return True. From Google developer

answered Mar 17 '22 at 16:20

Eneka

1
1

How to make `onClick()` in xml call two methods?

5 Answers5