BaseLoader.java

public abstract class AbstractNetService<K> extends AsyncTaskLoader<K> {

    private Bundle bundle;
    private K mData;

    public AbstractNetService(Context context, Bundle bundle) {
        super(context);
        this.bundle = bundle;
        onContentChanged();
    }

    @Override
    protected void onStartLoading() {
        if (mData != null) {
            // Deliver any previously loaded data immediately.
            deliverResult(mData);
        }

        if (takeContentChanged() || mData == null) {
            // When the observer detects a change, it should call onContentChanged()
            // on the Loader, which will cause the next call to takeContentChanged()
            // to return true. If this is ever the case (or if the current data is
            // null), we force a new load.
            forceLoad();
        }
    }

    @Override
    protected void onStopLoading() {
        // The Loader is in a stopped state, so we should attempt to cancel the
        // current load (if there is one).
        cancelLoad();

        // Note that we leave the observer as is. Loaders in a stopped state
        // should still monitor the data source for changes so that the Loader
        // will know to force a new load if it is ever started again.
    }

    @Override
    protected void onReset() {
        // Ensure the loader has been stopped.
        onStopLoading();

        // At this point we can release the resources associated with 'mData'.
        if (mData != null) {
            releaseResources(mData);
            mData = null;
        }
    }

    @Override
    public void onCanceled(K data) {
        // Attempt to cancel the current asynchronous load.
        super.onCanceled(data);

        // The load has been canceled, so we should release the resources
        // associated with 'data'.
        releaseResources(data);
    }

    @Override
    public void deliverResult(K data) {
        if (isReset()) {
            // The Loader has been reset; ignore the result and invalidate the data.
            releaseResources(data);
            return;
        }

        // Hold a reference to the old data so it doesn't get garbage collected.
        // We must protect it until the new data has been delivered.
        K oldData = mData;
        mData = data;

        if (isStarted()) {
            // If the Loader is in a started state, deliver the results to the
            // client. The superclass method does this for us.
            super.deliverResult(data);
        }

        // Invalidate the old data as we don't need it any more.
        if (oldData != null && oldData != data) {
            releaseResources(oldData);
        }
    }

    @Override
    public K loadInBackground() {
        try {
            RestAdapter restAdapter = new RestAdapter.Builder()
                    .setEndpoint(NetData.URL)
                    .build();
            return loadInBackground(restAdapter, bundle);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    protected abstract K loadInBackground(RestAdapter restAdapter, Bundle args) throws Exception;

    /**
     * /For a simple List, there is nothing to do. For something like a Cursor, we
     * would close it in this method. All resources associated with the Loader
     * should be released here.
     *
     * @param data
     */
    protected abstract void releaseResources(K data);
}