adapter for observe added

src/main/java/ru/touchin/roboswag/components/listing/adapters/ObservableCollectionAdapter.java

@@ -0,0 +1,164 @@
+/*
+ *  Copyright (c) 2015 RoboSwag (Gavriil Sitnikov, Vsevolod Ivanov)
+ *
+ *  This file is part of RoboSwag library.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+
+package ru.touchin.roboswag.components.listing.adapters;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v7.widget.RecyclerView;
+import android.view.ViewGroup;
+
+import java.util.List;
+
+import ru.touchin.roboswag.components.R;
+import ru.touchin.roboswag.components.utils.UiUtils;
+import ru.touchin.roboswag.core.log.Lc;
+import ru.touchin.roboswag.core.observables.collections.Change;
+import ru.touchin.roboswag.core.observables.collections.ObservableCollection;
+import ru.touchin.roboswag.core.observables.collections.ObservableList;
+import ru.touchin.roboswag.core.utils.ShouldNotHappenException;
+import rx.Subscription;
+import rx.android.schedulers.AndroidSchedulers;
+import rx.functions.Actions;
+
+/**
+ * Created by Gavriil Sitnikov on 20/11/2015.
+ * TODO: fill description
+ */
+public abstract class ObservableCollectionAdapter<TItem, TViewHolder extends RecyclerView.ViewHolder>
+        extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
+
+    private static final int PRE_LOADING_COUNT = 10;
+
+    private static final int LOADED_ITEM_TYPE = R.id.LOADED_ITEM_TYPE;
+
+    @Nullable
+    private OnItemClickListener<TItem> onItemClickListener;
+    @Nullable
+    private ObservableCollection<TItem> observableCollection;
+    @Nullable
+    private Subscription itemsProviderSubscription;
+
+    protected long getItemClickDelay() {
+        return UiUtils.RIPPLE_EFFECT_DELAY;
+    }
+
+    public void setItems(@NonNull final List<TItem> items) {
+        setObservableCollection(new ObservableList<>(items));
+    }
+
+    @Nullable
+    public ObservableCollection<TItem> getObservableCollection() {
+        return observableCollection;
+    }
+
+    protected int itemsOffset() {
+        return 0;
+    }
+
+    public void setObservableCollection(@Nullable final ObservableCollection<TItem> observableCollection) {
+        if (itemsProviderSubscription != null) {
+            itemsProviderSubscription.unsubscribe();
+            itemsProviderSubscription = null;
+        }
+        this.observableCollection = observableCollection;
+        notifyDataSetChanged();
+        if (this.observableCollection != null) {
+            itemsProviderSubscription = this.observableCollection.observeChanges()
+                    .observeOn(AndroidSchedulers.mainThread())
+                    .subscribe(this::onItemsChanged);
+        }
+    }
+
+    protected void onItemsChanged(@NonNull final Change change) {
+        switch (change.getType()) {
+            case INSERTED:
+                notifyItemRangeInserted(change.getStart() + itemsOffset(), change.getCount());
+                break;
+            case CHANGED:
+                notifyItemRangeChanged(change.getStart() + itemsOffset(), change.getCount());
+                break;
+            case REMOVED:
+                notifyItemRangeRemoved(change.getStart() + itemsOffset(), change.getCount());
+                break;
+            default:
+                Lc.assertion("Not supported " + change.getType());
+                break;
+        }
+    }
+
+    public void setOnItemClickListener(@Nullable final OnItemClickListener<TItem> onItemClickListener) {
+        this.onItemClickListener = onItemClickListener;
+        notifyDataSetChanged();
+    }
+
+    @Override
+    public int getItemViewType(final int position) {
+        return LOADED_ITEM_TYPE;
+    }
+
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
+        return onCreateItemViewHolder(parent, viewType);
+    }
+
+    public abstract TViewHolder onCreateItemViewHolder(final ViewGroup parent, final int viewType);
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
+        final TItem item = getItem(position);
+        if (observableCollection == null) {
+            Lc.assertion(new ShouldNotHappenException("Item at" + position + " should not be null"));
+            return;
+        }
+        onBindItemToViewHolder((TViewHolder) holder, position, item);
+        observableCollection.loadRange(Math.max(0, position - PRE_LOADING_COUNT), position + PRE_LOADING_COUNT).first()
+                .subscribe(Actions.empty(), Actions.empty());
+        if (onItemClickListener != null && !isOnClickListenerDisabled(item)) {
+            UiUtils.setOnRippleClickListener(holder.itemView, () -> onItemClickListener.onItemClicked(item, position), getItemClickDelay());
+        }
+    }
+
+    protected abstract void onBindItemToViewHolder(@NonNull final TViewHolder holder, final int position, @NonNull TItem item);
+
+    @NonNull
+    public TItem getItem(final int position) {
+        if (observableCollection == null) {
+            throw new ShouldNotHappenException();
+        }
+        return observableCollection.get(position);
+    }
+
+    @Override
+    public int getItemCount() {
+        return observableCollection != null ? observableCollection.size() : 0;
+    }
+
+    public boolean isOnClickListenerDisabled(@NonNull final TItem item) {
+        return false;
+    }
+
+    public interface OnItemClickListener<TItem> {
+
+        void onItemClicked(@NonNull TItem item, int position);
+
+    }
+
+}