Android BindingAdapter execution order?

Question

I need to understand how the data binding library determines the execution order for its BindingAdapters. If I have two BindingAdapters for the view, and if the view has both attributes corresponding to these BindingAdapters, how will it determine which adapter will be executed first? I ask because execution order matters in my case.

I have the following BindingAdapter / s:

public class SpinnerBindingAdapter {

    @BindingAdapter(value = {"entries"})
    public static void setEntries(Spinner spinner, List<? extends SpinnerItem> spinnerItems) {

        for (int i = 0; i < spinnerItems.size(); i++) {
            spinnerItems.get(i).setIndex(i);
        }
        ArrayAdapter<? extends SpinnerItem> adapter =
                new ArrayAdapter<>(spinner.getContext(), R.layout.spinner_item, spinnerItems);
        spinner.setAdapter(adapter);
    }

    @InverseBindingAdapter(attribute = "selectedItem", event = "selectedItemAttrChanged")
    public static Object getSelectedItem(Spinner spinner) {

        Object selectedItem = spinner.getSelectedItem();

        return selectedItem;
    }

    @BindingAdapter(value = {"selectedItem"})
    public static void setSelectedItem(Spinner spinner, SpinnerItem spinnerItem) {
        if (spinner.getAdapter() == null) {
            return;
        }
        // Other code omitted for simplicity
    }

    @BindingAdapter(value = {"selectedItemAttrChanged"}, requireAll = false)
    public static void setOnItemSelectedListener(Spinner spinner, final InverseBindingListener selectedItemChange) {
        if (selectedItemChange == null) {
            spinner.setOnItemSelectedListener(null);
        } else {
            spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

                @Override
                public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                    selectedItemChange.onChange();
                }

                @Override
                public void onNothingSelected(AdapterView<?> parent) {

                }
            });
        }
    }
}

And this is how I populate Spinner and set the selection:

<Spinner
    android:id="@+id/spinner_system_activity_edit_tracker_unit"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="fill_horizontal"
    app:entries="@{DatabaseModel.queryForAll()}"
    app:selectedItem="@={object.selectedItem}"/>

DatabaseModel.queryForAll is a static method that queries the database and returns a list of objects that are then passed to the BindingAdapter. The BindingAdapter takes this list, updates each of its elements with an index, and sets it as an adapter for the counter.

- , " " setSelectedItem . , . , spinner.getAdapter() null setSelectedItem. , .

Answer 1

Android . - , . selectedItem .

@BindingAdapter(value = {"selectedItem", "entries"}, requireAll = false)
public static void setSelectedItem(Spinner spinner, SpinnerItem spinnerItem,
        List<? extends SpinnerItem> spinnerItems) {
    // Set entries attribute when provided
    if (spinnerItems != null) {
        for (int i = 0; i < spinnerItems.size(); i++) {
            spinnerItems.get(i).setIndex(i);
        }
        ArrayAdapter<? extends SpinnerItem> adapter =
            new ArrayAdapter<>(spinner.getContext(), R.layout.spinner_item, spinnerItems);
        spinner.setAdapter(adapter);
    }
    // set selectedItem attribute when provided
    if (spinnerItem != null) {
        if (spinner.getAdapter() == null) {
            return;
        }
        // Other code omitted for simplicity
    }
}