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/*
* Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.android.databinding;
import androidx.databinding.DataBindingUtil;
import androidx.databinding.ObservableList;
import androidx.databinding.ViewDataBinding;
import androidx.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.wireguard.android.BR;
import java.lang.ref.WeakReference;
import java.util.Objects;
/**
* Helper class for binding an ObservableList to the children of a ViewGroup.
*/
class ItemChangeListener<T> {
private final OnListChangedCallback<T> callback = new OnListChangedCallback<>(this);
private final ViewGroup container;
private final int layoutId;
private final LayoutInflater layoutInflater;
@Nullable private ObservableList<T> list;
ItemChangeListener(final ViewGroup container, final int layoutId) {
this.container = container;
this.layoutId = layoutId;
layoutInflater = LayoutInflater.from(container.getContext());
}
private View getView(final int position, @Nullable final View convertView) {
ViewDataBinding binding = convertView != null ? DataBindingUtil.getBinding(convertView) : null;
if (binding == null) {
binding = DataBindingUtil.inflate(layoutInflater, layoutId, container, false);
}
Objects.requireNonNull(list, "Trying to get a view while list is still null");
binding.setVariable(BR.collection, list);
binding.setVariable(BR.item, list.get(position));
binding.executePendingBindings();
return binding.getRoot();
}
void setList(@Nullable final ObservableList<T> newList) {
if (list != null)
list.removeOnListChangedCallback(callback);
list = newList;
if (list != null) {
list.addOnListChangedCallback(callback);
callback.onChanged(list);
} else {
container.removeAllViews();
}
}
private static final class OnListChangedCallback<T>
extends ObservableList.OnListChangedCallback<ObservableList<T>> {
private final WeakReference<ItemChangeListener<T>> weakListener;
private OnListChangedCallback(final ItemChangeListener<T> listener) {
weakListener = new WeakReference<>(listener);
}
@Override
public void onChanged(final ObservableList<T> sender) {
final ItemChangeListener<T> listener = weakListener.get();
if (listener != null) {
// TODO: recycle views
listener.container.removeAllViews();
for (int i = 0; i < sender.size(); ++i)
listener.container.addView(listener.getView(i, null));
} else {
sender.removeOnListChangedCallback(this);
}
}
@Override
public void onItemRangeChanged(final ObservableList<T> sender, final int positionStart,
final int itemCount) {
final ItemChangeListener<T> listener = weakListener.get();
if (listener != null) {
for (int i = positionStart; i < positionStart + itemCount; ++i) {
final View child = listener.container.getChildAt(i);
listener.container.removeViewAt(i);
listener.container.addView(listener.getView(i, child));
}
} else {
sender.removeOnListChangedCallback(this);
}
}
@Override
public void onItemRangeInserted(final ObservableList<T> sender, final int positionStart,
final int itemCount) {
final ItemChangeListener<T> listener = weakListener.get();
if (listener != null) {
for (int i = positionStart; i < positionStart + itemCount; ++i)
listener.container.addView(listener.getView(i, null));
} else {
sender.removeOnListChangedCallback(this);
}
}
@Override
public void onItemRangeMoved(final ObservableList<T> sender, final int fromPosition,
final int toPosition, final int itemCount) {
final ItemChangeListener<T> listener = weakListener.get();
if (listener != null) {
final View[] views = new View[itemCount];
for (int i = 0; i < itemCount; ++i)
views[i] = listener.container.getChildAt(fromPosition + i);
listener.container.removeViews(fromPosition, itemCount);
for (int i = 0; i < itemCount; ++i)
listener.container.addView(views[i], toPosition + i);
} else {
sender.removeOnListChangedCallback(this);
}
}
@Override
public void onItemRangeRemoved(final ObservableList<T> sender, final int positionStart,
final int itemCount) {
final ItemChangeListener<T> listener = weakListener.get();
if (listener != null) {
listener.container.removeViews(positionStart, itemCount);
} else {
sender.removeOnListChangedCallback(this);
}
}
}
}
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