Android Databinding onLongClick not working

Question

I have a text view to which I need to create a listener for onLongClick. Right now for the respective viewmodel it has a function sendLogs() which deals with the logic for onClick. If I change onClick to onLongClick function never get call. Is there any way to make it work for onLongClick?

onClick is directly linked to my model class function but not the onLongClick. So I think model class binding is correct but I may need some extra work here.

<data>
    <import type="android.view.View" />

    <variable
        type="com.aaa.bbb.viewmodel.SystemSettingsViewModel"
        name="systemSettings"
    </variable>
</data>

<TextView
    android:gravity="end"
    android:id="@+id/tv_logging"
    android:layout_centerVertical="true"
    android:layout_height="wrap_content"
    android:layout_marginRight="8dp"
    android:layout_width="wrap_content"
    android:onClick="@{() -> systemSettings.sendLogs()}"
    android:text="@string/enable_logs"
    android:textAlignment="viewEnd" />

@BurhanuddinRashidI added the binding part of the layout. That's all related to this issue. — M P Mathugama, Oct 11 '17 at 06:17
There was nothing that difficult you should have tried it, see my answer below. — Akshay Katariya, Oct 11 '17 at 06:21

M P Mathugama · Accepted Answer · 2017-10-13T09:14:18.023

52

I managed to work it correctly. I doubt this is properly documented.

In xml

android:onLongClick="@{(view) -> presenter.onLongClickOnHeading(view)}"

In presenter viewmodel class

public boolean onLongClickOnHeading(View v) { 
   //logic goes here
   return false; 
}

Note: this method signature should be exactly in this format. Otherwise biding errors will be thrown at runtime.

edited Oct 13 '17 at 09:14

answered Oct 13 '17 at 09:03

M P Mathugama

1,418
1
20
31

10

The return parameter for method signature must " boolean " – Jovin Jan 24 '18 at 14:02
2

This "must be boolean" is not the case for regular OnClick, and AS will not show that this is the cause in build fail. So be very aware of this. – MwBakker Dec 19 '18 at 08:52
Thanks for the return parameter for the method – Ho Luong Aug 15 '20 at 05:45
This post is still helpful in 2022 !! – Terry Wilkinson Jan 09 '22 at 01:10

score 5 · Answer 2 · answered Jul 27 '20 at 06:05

Here is the complete the code.

There is no such attribute for long click. So we have to create a binding adapter.

BindingUtils.kt

object BindingUtils {

    private const val ON_LONG_CLICK = "android:onLongClick"

    @JvmStatic
    @BindingAdapter(ON_LONG_CLICK)
    fun setOnLongClickListener(
        view: View,
        func : () -> Unit
    ) {
        view.setOnLongClickListener {
            func()
            return@setOnLongClickListener true
        }
    }
}

Layout

<androidx.constraintlayout.widget.ConstraintLayout
    android:background="?android:attr/selectableItemBackground"
    android:clickable="true"
    android:focusable="true"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:onLongClick="@{() -> vm.onLongClick()}"/>

At one .xml file i used the 'onLongClick' without this method and it worked with no problem but at the other it did not, showing strange compile error. It was resolved when using this method. Thx. — epic, Sep 12 '20 at 13:08

score 2 · Answer 3 · answered Feb 12 '18 at 01:39

For it to work, the part in parenthesis has to match the method signature from the interface View.OnLongClickListener which looks like this :

boolean onLongClick(View view);

So this is how I got it to work :

<View
...
android:onLongClick="@{(view) -> listener.onLongClick(view, viewmodel)}"/>
...

younes · Answer 4 · 2020-10-22T11:20:39.003

1

In the xml section, you must refer to the Boolean return function, such as the following code, so as not to get into trouble.in build project android studio

in xml

android:onLongClick="@{(view) -> presenter.onLongClick(view)}"

in java

  public boolean onLongClick(View v) {
    return false;
}

edited Oct 22 '20 at 11:20

answered Oct 22 '20 at 11:14

younes

742
7
8

score 0 · Answer 5 · answered Oct 12 '17 at 04:17

0

You should look into this document

OnLongClick is as easy as onClick

Within your SystemSettingsViewModel you can have

public boolean onLongClick(){}

and in xml

android:onLongClick="@{() -> presenter.onLongClick()}"

answered Oct 12 '17 at 04:17

Ravi

34,851
21
122
183

2

Yes it should be. I read that document & tried out earlier. But no result. Compiler failed to compile with android:onLongClick() – M P Mathugama Oct 13 '17 at 07:28
2

Dealtwith the same issue, also the debugger does not show the exact problem but 150 lines of emptiness untill it tells me "1 error" as summary My solution was that the method in the listener/handler MUST be a boolean – MwBakker Dec 19 '18 at 08:46

score 0 · Answer 6 · answered Oct 21 '19 at 06:25

As mentioned in the Google documentation Link there is no problem with what you wrote.

This is a sample of OnLongClick in XML:

android:onLongClick="@{(theView) -> presenter.onLongClick(theView, task)}"

class Presenter {
    fun onLongClick(view: View, task: Task): Boolean { }
}

Android Databinding onLongClick not working

6 Answers6