Custom SeekBar listener databinding

Question

I'm trying to set listener on custom SeekBar (https://github.com/warkiz/IndicatorSeekBar) using Android Databinding. In standard SeekBar I'm setting onProgressChanged listener this way:
fragment's XML:

<SeekBar
    ...
    android:onProgressChanged="@{viewModel::seekBarStopTracking}"
    ... 
/>

Fragment's ViewModel:

public void seekBarStopTracking(SeekBar view, int progress, boolean fromUser) {
       
}

I'm trying to do the same with IndicatorSeekBar, however it has a bit different listeners:
Example from github:

seekBar.setOnSeekChangeListener(new OnSeekChangeListener() {
    @Override
    public void onSeeking(SeekParams seekParams) {
    }

    @Override
    public void onStartTrackingTouch(IndicatorSeekBar seekBar) {
    }

    @Override
    public void onStopTrackingTouch(IndicatorSeekBar seekBar) {
    }
});

XML:

<com.warkiz.widget.IndicatorSeekBar
    ...
    app:onSeeking="@{viewModel::seeking}"
    ...
/>

ViewModel:

public void seeking(SeekParams params){
    
}

also tried:

public void seeking(IndicatorSeekBar seekBar, SeekParams params){
    
}

But result is the same:

[databinding] {"msg":"Could not resolve viewModel::seeking as a listener.

What I'm doing wrong? Thanks

Answer 1

This is a custom view, so you need to write your own Binding Adapters. Here is the solution:

Step 1: Create a binding class

IndicatorSeekBarBindingAdapter.java

public class IndicatorSeekBarBindingAdapter {

    @BindingAdapter(value = {"app:onSeeking", "app:onStartTrackingTouch",
            "app:onStopTrackingTouch"}, requireAll = false)
    public static void setOnSeekBarChangeListener(IndicatorSeekBar seekBar,
                                                  final OnSeeking seeking,
                                                  final OnStartTrackingTouch start,
                                                  final OnStopTrackingTouch stop) {
        if (seeking != null || start != null || stop != null) {
            seekBar.setOnSeekChangeListener(new OnSeekChangeListener() {
                @Override
                public void onSeeking(SeekParams seekParams) {
                    if (seeking != null) {
                        seeking.onSeeking(seekBar, seekParams);
                    }
                }

                @Override
                public void onStartTrackingTouch(IndicatorSeekBar seekBar) {
                    if (start != null) {
                        start.onStartTrackingTouch(seekBar);
                    }
                }

                @Override
                public void onStopTrackingTouch(IndicatorSeekBar seekBar) {
                    if (stop != null) {
                        stop.onStopTrackingTouch(seekBar);
                    }
                }
            });
        }
    }

    public interface OnSeeking {
        void onSeeking(IndicatorSeekBar seekBar, SeekParams seekParams);
    }

    public interface OnStartTrackingTouch {
        void onStartTrackingTouch(IndicatorSeekBar seekBar);
    }

    public interface OnStopTrackingTouch {
        void onStopTrackingTouch(IndicatorSeekBar seekBar);
    }
}

Step 2: Add the following code into your view model class.

public class MyViewModel extends ViewModel {

    public void onSeeking(IndicatorSeekBar seekBar, SeekParams seekParams) {
        Log.i("TAG", "onSeeking: " + seekParams.progress);
    }

    public void onStartTrackingTouch(IndicatorSeekBar seekBar) {
        Log.i("TAG", "onStartTrackingTouch: " + seekBar.getProgress());
    }

    public void onStopTrackingTouch(IndicatorSeekBar seekBar) {
        Log.i("TAG", "onStopTrackingTouch: " + seekBar.getProgress());
    }
}

Step 3: Use it from layout xml file

<com.warkiz.widget.IndicatorSeekBar
    android:id="@+id/seekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:onSeeking="@{viewModel::onSeeking}"
    app:onStartTrackingTouch="@{viewModel::onStartTrackingTouch}"
    app:onStopTrackingTouch="@{viewModel::onStopTrackingTouch}" />