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/*
* Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.android.databinding;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import com.wireguard.android.BR;
import com.wireguard.android.util.ObservableKeyedList;
import com.wireguard.util.Keyed;
import com.wireguard.util.NonNullForAll;
import java.lang.ref.WeakReference;
import androidx.annotation.Nullable;
import androidx.databinding.DataBindingUtil;
import androidx.databinding.ObservableList;
import androidx.databinding.ViewDataBinding;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.Adapter;
/**
* A generic {@code RecyclerView.Adapter} backed by a {@code ObservableKeyedList}.
*/
@NonNullForAll
public class ObservableKeyedRecyclerViewAdapter<K, E extends Keyed<? extends K>> extends Adapter<ObservableKeyedRecyclerViewAdapter.ViewHolder> {
private final OnListChangedCallback<E> callback = new OnListChangedCallback<>(this);
private final int layoutId;
private final LayoutInflater layoutInflater;
@Nullable private ObservableKeyedList<K, E> list;
@Nullable private RowConfigurationHandler rowConfigurationHandler;
ObservableKeyedRecyclerViewAdapter(final Context context, final int layoutId,
final ObservableKeyedList<K, E> list) {
this.layoutId = layoutId;
layoutInflater = LayoutInflater.from(context);
setList(list);
}
@Nullable
private E getItem(final int position) {
if (list == null || position < 0 || position >= list.size())
return null;
return list.get(position);
}
@Override
public int getItemCount() {
return list != null ? list.size() : 0;
}
@Override
public long getItemId(final int position) {
final K key = getKey(position);
return key != null ? key.hashCode() : -1;
}
@Nullable
private K getKey(final int position) {
final E item = getItem(position);
return item != null ? item.getKey() : null;
}
@SuppressWarnings("unchecked")
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
holder.binding.setVariable(BR.collection, list);
holder.binding.setVariable(BR.key, getKey(position));
holder.binding.setVariable(BR.item, getItem(position));
holder.binding.executePendingBindings();
if (rowConfigurationHandler != null) {
final E item = getItem(position);
if (item != null) {
rowConfigurationHandler.onConfigureRow(holder.binding, item, position);
}
}
}
@Override
public ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
return new ViewHolder(DataBindingUtil.inflate(layoutInflater, layoutId, parent, false));
}
void setList(@Nullable final ObservableKeyedList<K, E> newList) {
if (list != null)
list.removeOnListChangedCallback(callback);
list = newList;
if (list != null) {
list.addOnListChangedCallback(callback);
}
notifyDataSetChanged();
}
void setRowConfigurationHandler(final RowConfigurationHandler rowConfigurationHandler) {
this.rowConfigurationHandler = rowConfigurationHandler;
}
public interface RowConfigurationHandler<B extends ViewDataBinding, T> {
void onConfigureRow(B binding, T item, int position);
}
private static final class OnListChangedCallback<E extends Keyed<?>>
extends ObservableList.OnListChangedCallback<ObservableList<E>> {
private final WeakReference<ObservableKeyedRecyclerViewAdapter<?, E>> weakAdapter;
private OnListChangedCallback(final ObservableKeyedRecyclerViewAdapter<?, E> adapter) {
weakAdapter = new WeakReference<>(adapter);
}
@Override
public void onChanged(final ObservableList<E> sender) {
final ObservableKeyedRecyclerViewAdapter 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);
}
}
public static class ViewHolder extends RecyclerView.ViewHolder {
final ViewDataBinding binding;
public ViewHolder(final ViewDataBinding binding) {
super(binding.getRoot());
this.binding = binding;
}
}
}
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