eu.monniot.memoArcher.loaders.SimpleCursorLoader.java Source code

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Here is the source code for eu.monniot.memoArcher.loaders.SimpleCursorLoader.java

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/*
* Copyright 2012 CodeSlap - Cristian Castiblanco
*
* 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 eu.monniot.memoArcher.loaders;

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

/**
* Used to write apps that run on platforms prior to Android 3.0. When running
* on Android 3.0 or above, this implementation is still used; it does not try
* to switch to the framework's implementation. See the framework SDK
* documentation for a class overview.
*
* This was based on the CursorLoader class
*
* @author cristian
*/
public abstract class SimpleCursorLoader extends AsyncTaskLoader<Cursor> {
    private Cursor mCursor;

    public SimpleCursorLoader(Context context) {
        super(context);
    }

    /* Runs on a worker thread */
    @Override
    public abstract Cursor loadInBackground();

    /* Runs on the UI thread */
    @Override
    public void deliverResult(Cursor cursor) {
        if (isReset()) {
            // An async query came in while the loader is stopped
            if (cursor != null)
                cursor.close();

            return;
        }

        Cursor oldCursor = mCursor;
        mCursor = cursor;

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

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

    /**
    * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks
    * will be called on the UI thread. If a previous load has been completed and is still valid
    * the result may be passed to the callbacks immediately.
    * <p/>
    * Must be called from the UI thread
    */
    @Override
    protected void onStartLoading() {
        if (mCursor != null)
            deliverResult(mCursor);

        if (takeContentChanged() || mCursor == null)
            forceLoad();
    }

    /**
    * Must be called from the UI thread
    */
    @Override
    protected void onStopLoading() {
        // Attempt to cancel the current load task if possible.
        cancelLoad();
    }

    @Override
    public void onCanceled(Cursor cursor) {
        if (cursor != null && !cursor.isClosed())
            cursor.close();
    }

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

        // Ensure the loader is stopped
        onStopLoading();

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