com.granita.tasks.groupings.cursorloaders.CustomCursorLoader.java Source code

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Here is the source code for com.granita.tasks.groupings.cursorloaders.CustomCursorLoader.java

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/*
 * Copyright (C) 2013 Marten Gajda <marten@dmfs.org>
 *
 * 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 com.granita.tasks.groupings.cursorloaders;

import android.content.Context;
import android.database.Cursor;
import android.support.v4.content.Loader;

/**
 * A very simple {@link Loader} that returns the {@link Cursor} from a {@link AbstractCustomCursorFactory}.
 * 
 * @author Marten Gajda <marten@dmfs.org>
 */
public class CustomCursorLoader extends Loader<Cursor> {
    /**
     * The current Cursor.
     */
    private Cursor mCursor;

    /**
     * The factory that creates our Cursor.
     */
    private final AbstractCustomCursorFactory mCursorFactory;

    public CustomCursorLoader(Context context, AbstractCustomCursorFactory factory) {
        super(context);

        mCursorFactory = factory;
    }

    @Override
    public void deliverResult(Cursor cursor) {
        if (isReset()) {
            // An async query came in while the loader is stopped
            if (cursor != null && !cursor.isClosed()) {
                cursor.close();
            }
            return;
        }
        Cursor oldCursor = mCursor;
        mCursor = cursor;

        if (isStarted()) {
            super.deliverResult(cursor);
        }

        if (oldCursor != null && oldCursor != cursor && !oldCursor.isClosed()) {
            oldCursor.close();
        }
    }

    @Override
    protected void onStartLoading() {
        if (mCursor == null || takeContentChanged()) {
            // deliver a new cursor, deliverResult will take care of the old one if any
            deliverResult(mCursorFactory.getCursor());
        } else {
            // just deliver the same cursor
            deliverResult(mCursor);
        }
    }

    @Override
    protected void onForceLoad() {
        // just create a new cursor, deliverResult will take care of storing the new cursor and closing the old one
        deliverResult(mCursorFactory.getCursor());
    }

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

        onStopLoading();

        // ensure the cursor is closed before we release it
        if (mCursor != null && !mCursor.isClosed()) {
            mCursor.close();
        }

        mCursor = null;
    }
}