databinding: Add an adapter for the KeyedObservableList

This adapter actually finally implements stable IDs correctly.

Signed-off-by: Samuel Holland <samuel@sholland.org>
This commit is contained in:
Samuel Holland 2018-01-06 03:58:43 -06:00
parent e24654ce7c
commit c73287f64b

View File

@ -0,0 +1,127 @@
package com.wireguard.android.databinding;
import android.content.Context;
import android.databinding.DataBindingUtil;
import android.databinding.ObservableList;
import android.databinding.ViewDataBinding;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import com.wireguard.android.BR;
import com.wireguard.android.util.Keyed;
import com.wireguard.android.util.KeyedObservableList;
import java.lang.ref.WeakReference;
/**
* A generic {@code ListAdapter} backed by a {@code KeyedObservableList}.
*/
class KeyedObservableListAdapter<K, E extends Keyed<? extends K>> extends BaseAdapter {
private final OnListChangedCallback<E> callback = new OnListChangedCallback<>(this);
private final int layoutId;
private final LayoutInflater layoutInflater;
private KeyedObservableList<K, E> list;
KeyedObservableListAdapter(final Context context, final int layoutId,
final KeyedObservableList<K, E> list) {
this.layoutId = layoutId;
layoutInflater = LayoutInflater.from(context);
setList(list);
}
@Override
public int getCount() {
return list != null ? list.size() : 0;
}
@Override
public E getItem(final int position) {
if (list == null || position < 0 || position >= list.size())
return null;
return list.get(position);
}
@Override
public long getItemId(final int position) {
final K key = getKey(position);
return key != null ? key.hashCode() : -1;
}
private K getKey(final int position) {
final E item = getItem(position);
return item != null ? item.getKey() : null;
}
@Override
public View getView(final int position, final View convertView, final ViewGroup parent) {
ViewDataBinding binding = DataBindingUtil.getBinding(convertView);
if (binding == null)
binding = DataBindingUtil.inflate(layoutInflater, layoutId, parent, false);
binding.setVariable(BR.collection, list);
binding.setVariable(BR.key, getKey(position));
binding.setVariable(BR.item, getItem(position));
binding.executePendingBindings();
return binding.getRoot();
}
@Override
public boolean hasStableIds() {
return true;
}
void setList(final KeyedObservableList<K, E> newList) {
if (list != null)
list.removeOnListChangedCallback(callback);
list = newList;
if (list != null) {
list.addOnListChangedCallback(callback);
}
notifyDataSetChanged();
}
private static final class OnListChangedCallback<E extends Keyed<?>>
extends ObservableList.OnListChangedCallback<ObservableList<E>> {
private final WeakReference<KeyedObservableListAdapter<?, E>> weakAdapter;
private OnListChangedCallback(final KeyedObservableListAdapter<?, E> adapter) {
weakAdapter = new WeakReference<>(adapter);
}
@Override
public void onChanged(final ObservableList<E> sender) {
final KeyedObservableListAdapter adapter = weakAdapter.get();
if (adapter != null)
adapter.notifyDataSetChanged();
else
sender.removeOnListChangedCallback(this);
}
@Override
public void onItemRangeChanged(final ObservableList<E> sender, final int positionStart,
final int itemCount) {
onChanged(sender);
}
@Override
public void onItemRangeInserted(final ObservableList<E> sender, final int positionStart,
final int itemCount) {
onChanged(sender);
}
@Override
public void onItemRangeMoved(final ObservableList<E> sender, final int fromPosition,
final int toPosition, final int itemCount) {
onChanged(sender);
}
@Override
public void onItemRangeRemoved(final ObservableList<E> sender, final int positionStart,
final int itemCount) {
onChanged(sender);
}
}
}