im.ene.lab.attiq.ui.fragment.RealmListFragment.java Source code

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Here is the source code for im.ene.lab.attiq.ui.fragment.RealmListFragment.java

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/*
 * Copyright 2016 eneim@Eneim Labs, nam@ene.im
 *
 * 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 im.ene.lab.attiq.ui.fragment;

import android.content.Context;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.support.v4.widget.SwipeRefreshLayout;
import android.view.View;
import de.greenrobot.event.EventBus;
import im.ene.lab.attiq.Attiq;
import im.ene.lab.attiq.data.api.ApiClient;
import im.ene.lab.attiq.ui.adapters.AttiqListAdapter;
import im.ene.lab.attiq.ui.adapters.AttiqRealmListAdapter;
import im.ene.lab.attiq.util.UIUtil;
import im.ene.lab.attiq.util.event.Event;
import im.ene.lab.attiq.util.event.ItemsEvent;
import io.realm.Realm;
import io.realm.RealmAsyncTask;
import io.realm.RealmChangeListener;
import io.realm.RealmObject;
import java.util.List;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

/**
 * Created by eneim on 12/13/15.
 */
public abstract class RealmListFragment<E extends RealmObject> extends ListFragment<E>
        implements SwipeRefreshLayout.OnRefreshListener, Handler.Callback, Callback<List<E>> {

    private static final String TAG = "RealmListFragment";

    protected Realm mRealm;
    protected RealmAsyncTask mTransactionTask;

    // User a handler to prevent too frequently calling of methods. For example Realm may trigger
    // #onChange a lot of time, since it doesn't support type-specific change event now. So we
    // should queue the Change event up, and remove the duplicated ones to save resources
    private Handler mHandler = new Handler(this);

    private RealmChangeListener mDataChangeListener = new RealmChangeListener() {
        @Override
        public void onChange() {
            mHandler.removeMessages(MESSAGE_UPDATE_DATA);
            mHandler.sendEmptyMessageDelayed(MESSAGE_UPDATE_DATA, 200);
        }
    };

    @Override
    protected void loadReload() {
        boolean isRefreshing = mSwipeRefreshLayout != null && mSwipeRefreshLayout.isRefreshing();
        boolean isLoadingMore = !isRefreshing;
        if (isLoadingMore) {
            mPage++;
        } else {
            mPage = DEFAULT_FIRST_PAGE;
        }

        // Show loading view only when we don't have any item and we want to renew the list
        if (isRefreshing && mAdapter.getItemCount() == 0) {
            mLoadingView.setVisibility(View.VISIBLE);
        }

        mAdapter.loadItems(isLoadingMore, mPage, DEFAULT_THRESHOLD, null, this);
    }

    @NonNull
    @Override
    protected AttiqListAdapter<E> createAdapter() {
        return createRealmAdapter();
    }

    @NonNull
    protected abstract AttiqRealmListAdapter<E> createRealmAdapter();

    @Override
    public void onRefresh() {
        if (mSwipeRefreshLayout != null) {
            mSwipeRefreshLayout.setRefreshing(true);
            mHandler.removeMessages(MESSAGE_LOAD_RELOAD);
            mHandler.sendEmptyMessageDelayed(MESSAGE_LOAD_RELOAD, 200);
        }
    }

    @Override
    public void onResponse(Call<List<E>> call, Response<List<E>> response) {
        if (response.code() != 200) {
            EventBus.getDefault().post(new ItemsEvent(eventTag(), false,
                    new Event.Error(response.code(), ApiClient.parseError(response).message), mPage));
        } else {
            final List<E> items = response.body();
            if (!UIUtil.isEmpty(items)) {
                mTransactionTask = Attiq.realm().executeTransaction(new Realm.Transaction() {
                    @Override
                    public void execute(Realm realm) {
                        realm.copyToRealmOrUpdate(items);
                    }
                }, new Realm.Transaction.Callback() {
                    @Override
                    public void onSuccess() {
                        EventBus.getDefault().post(new ItemsEvent(eventTag(), true, null, mPage));
                    }

                    @Override
                    public void onError(Exception e) {
                        EventBus.getDefault().post(new ItemsEvent(eventTag(), false,
                                new Event.Error(Event.Error.ERROR_UNKNOWN, e.getLocalizedMessage()), mPage));
                    }
                });
            } else {
                EventBus.getDefault().post(new ItemsEvent(eventTag(), true, null, mPage));
            }
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mRealm = Attiq.realm();
        mRealm.addChangeListener(mDataChangeListener);
    }

    @Override
    public void onDetach() {
        if (mRealm != null) {
            mRealm.removeChangeListener(mDataChangeListener);
            mRealm.close();
        }
        mDataChangeListener = null;
        super.onDetach();
    }

    @Override
    public void onPause() {
        super.onPause();
        if (mTransactionTask != null && !mTransactionTask.isCancelled()) {
            mTransactionTask.cancel();
        }
    }
}