AsyncLoader.java

/*
 *  Copyright (C) 2013-2016 Stichting Akvo (Akvo Foundation)
 *
 *  This file is part of Akvo Flow.
 *
 *  Akvo Flow is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Akvo Flow is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Akvo Flow.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.akvo.flow.data.loader.base;

import android.content.Context;
import android.support.v4.content.AsyncTaskLoader;

public abstract class AsyncLoader<T> extends AsyncTaskLoader<T> {
    private T mData;

    public AsyncLoader(Context context) {
        super(context);
    }
    
    @Override
    public void deliverResult(T data) {
        if (isReset()) {
            // An async query came in while the loader is stopped
            return;
        }

        this.mData = data;
        super.deliverResult(data);
    }

    @Override
    protected void onStartLoading() {
        if (mData != null) {
            deliverResult(mData);
        }

        if (takeContentChanged() || mData == null) {
            forceLoad();
        }
    }

    @Override
    protected void onStopLoading() {
        // Attempt to cancel the current load task if possible.
        cancelLoad();
    }

    @Override
    protected void onReset() {
        super.onReset();

        // Ensure the loader is stopped
        onStopLoading();

        mData = null;
    }
}