com.yy.m.filechooser.FileLoader.java Source code

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Here is the source code for com.yy.m.filechooser.FileLoader.java

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/* 
 * Copyright (C) 2012 Paul Burke
 * 
 * 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.yy.m.filechooser;

import java.io.File;
import java.io.FileFilter;
import java.util.List;

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

import com.yy.m.filechooser.utils.FileUtils;

/**
 * Loader that returns a list of Files in a given file path.
 * 
 * @version 2012-10-28
 * 
 * @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;
    private String mFilter;

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

    @Override
    public List<File> loadInBackground() {
        return FileUtils.getFileList(mPath, mFilter == null ? null : new FileFilter() {
            @Override
            public boolean accept(File f) {
                final String fileName = f.getName().toLowerCase();
                return f.isFile() && !fileName.startsWith(FileUtils.HIDDEN_PREFIX)
                        && fileName.endsWith("." + mFilter.toLowerCase());
            }

        });
    }

    @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;
        }
    }
}