Android Open Source - coltrane File Loader

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2013 Paul Burke/*from www .  ja  v a2s  .c  o m*/
 *
 * 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.mobilejazz.coltrane.library;

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

import com.mobilejazz.coltrane.library.utils.FileUtils;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Loader that returns a list of Files in a given file path.
 * 
 * @version 2013-12-11
 * @author paulburke (ipaulpro)
 */
public class FileLoader extends AsyncTaskLoader<List<File>> {

  private static final int FILE_OBSERVER_MASK = FileObserver.CREATE
      | FileObserver.DELETE | FileObserver.DELETE_SELF
      | FileObserver.MOVED_FROM | FileObserver.MOVED_TO
      | FileObserver.MODIFY | FileObserver.MOVE_SELF;

  private FileObserver mFileObserver;

  private List<File> mData;
  private String mPath;

  public FileLoader(Context context, String path) {
    super(context);
    this.mPath = path;
  }

  @Override
  public List<File> loadInBackground() {

        ArrayList<File> list = new ArrayList<File>();

        // Current directory File instance
        final File pathDir = new File(mPath);

        // List file in this directory with the directory filter
        final File[] dirs = pathDir.listFiles(FileUtils.sDirFilter);
        if (dirs != null) {
            // Sort the folders alphabetically
            Arrays.sort(dirs, FileUtils.sComparator);
            // Add each folder to the File list for the list adapter
            for (File dir : dirs)
                list.add(dir);
        }

        // List file in this directory with the file filter
        final File[] files = pathDir.listFiles(FileUtils.sFileFilter);
        if (files != null) {
            // Sort the files alphabetically
            Arrays.sort(files, FileUtils.sComparator);
            // Add each file to the File list for the list adapter
            for (File file : files)
                list.add(file);
        }

        return list;
  }

  @Override
  public void deliverResult(List<File> data) {
    if (isReset()) {
      onReleaseResources(data);
      return;
    }

    List<File> oldData = mData;
    mData = data;

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

    if (oldData != null && oldData != data)
      onReleaseResources(oldData);
  }

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

    if (mFileObserver == null) {
      mFileObserver = new FileObserver(mPath, FILE_OBSERVER_MASK) {
        @Override
        public void onEvent(int event, String path) {
          onContentChanged();
        }
      };
    }
    mFileObserver.startWatching();

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

  @Override
  protected void onStopLoading() {
    cancelLoad();
  }

  @Override
  protected void onReset() {
    onStopLoading();

    if (mData != null) {
      onReleaseResources(mData);
      mData = null;
    }
  }

  @Override
  public void onCanceled(List<File> data) {
    super.onCanceled(data);

    onReleaseResources(data);
  }

  protected void onReleaseResources(List<File> data) {

    if (mFileObserver != null) {
      mFileObserver.stopWatching();
      mFileObserver = null;
    }
  }
}

Java Source Code List

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