it.feio.android.omninotes.async.NoteLoaderTask.java Source code

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Here is the source code for it.feio.android.omninotes.async.NoteLoaderTask.java

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/*******************************************************************************
 * Copyright 2014 Federico Iosue (federico.iosue@gmail.com)
 * 
 * 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 it.feio.android.omninotes.async;

import it.feio.android.omninotes.db.DbHelper;
import it.feio.android.omninotes.models.Note;
import it.feio.android.omninotes.models.listeners.OnNotesLoadedListener;
import it.feio.android.omninotes.utils.Constants;

import java.lang.ref.WeakReference;
import java.lang.reflect.Method;
import java.util.ArrayList;

import android.app.Activity;
import android.os.AsyncTask;
import android.support.v4.app.Fragment;
import android.util.Log;

public class NoteLoaderTask extends AsyncTask<Object, Void, ArrayList<Note>> {

    private final WeakReference<Fragment> mFragmentReference;
    private final Activity mActivity;
    private OnNotesLoadedListener mOnNotesLoadedListener;

    public NoteLoaderTask(Fragment mFragment, OnNotesLoadedListener mOnNotesLoadedListener) {
        mFragmentReference = new WeakReference<Fragment>(mFragment);
        mActivity = mFragment.getActivity();
        this.mOnNotesLoadedListener = mOnNotesLoadedListener;
    }

    @SuppressWarnings("unchecked")
    @Override
    protected ArrayList<Note> doInBackground(Object... params) {
        ArrayList<Note> notes = new ArrayList<Note>();
        String methodName = params[0].toString();
        Object methodArgs = params[1];
        DbHelper db = DbHelper.getInstance(mActivity);

        // If null argument an empty list will be returned
        if (methodArgs == null) {
            return notes;
        }

        // Checks the argument class with reflection
        @SuppressWarnings("rawtypes")
        Class[] paramClass = new Class[1];
        if (Boolean.class.isAssignableFrom(methodArgs.getClass())) {
            paramClass[0] = Boolean.class;
        } else {
            paramClass[0] = String.class;
        }

        // Retrieves and calls the right method
        Method method;
        try {
            method = db.getClass().getDeclaredMethod(methodName, paramClass);
            notes = (ArrayList<Note>) method.invoke(db, paramClass[0].cast(methodArgs));
        } catch (Exception e) {
            Log.e(Constants.TAG, "Error retrieving notes", e);
        }

        return notes;
    }

    @Override
    protected void onPostExecute(ArrayList<Note> notes) {
        super.onPostExecute(notes);
        if (isAlive()) {
            mOnNotesLoadedListener.onNotesLoaded(notes);
        }
    }

    private boolean isAlive() {
        return mFragmentReference.get() != null && mFragmentReference.get().getActivity() != null
                && !mFragmentReference.get().getActivity().isFinishing() && mFragmentReference.get().isAdded();
    }
}