Android Open Source - filemanager Thumbnail Loader

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License

The source code is released under:
MIT License
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Java Source Code

/**
 * The MIT License (MIT)/*w  w w.  j a  va  2s.c o  m*/
 *
 * Copyright 2014 Binkery Huang <binkery@gmail.com>
 *
 * Oct 24, 2014
 */
package com.binkery.app.filemanager.fragments;

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

import com.binkery.app.filemanager.utils.Logs;

import android.app.ActivityManager;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.ThumbnailUtils;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.v4.util.LruCache;
import android.widget.ImageView;


public class ThumbnailLoader {

  private LruCache<String, Bitmap> mCache = null;
  private Context mContext;
  private ThumbnailLoader() {

  }

  public static ThumbnailLoader mLoader = null;

  public static ThumbnailLoader getInstance(Context context) {
    if (mLoader == null) {
      mLoader = new ThumbnailLoader();
      mLoader.mContext = context;
      final int memClass = ((ActivityManager) context
          .getSystemService(Context.ACTIVITY_SERVICE))
          .getMemoryClass();

      // Use 1/8th of the available memory for this memory cache.
      final int cacheSize = 1024 * 1024 * memClass / 8;
      mLoader.mCache = new LruCache<String, Bitmap>(cacheSize);
      mLoader.mTaskList = new ArrayList<ThumbnailLoader.TaskItem>();
    }
    return mLoader;
  }

  public Bitmap loadMicroThumbnail(String path, ImageView iv) {
    Bitmap bitmap = getBitmapFromMemCache(path);
    if (bitmap != null) {
      return bitmap;
    }
    for(TaskItem item : mTaskList){
      if(item.path.equals(path)){
        return null;
      }
    }
    
    TaskItem item = new TaskItem();
    item.path = path;
    item.imageview = iv;
    synchronized (mLock) {
      mTaskList.add(item);
    }
    if (!mIsLoadTaskRunning) {
      new ImageLoadTask().execute("");
    }
    return null;
  }

  private List<TaskItem> mTaskList = null;

  private class TaskItem {
    public String path;
    public ImageView imageview;
  }

  private void addBitmapToMemoryCache(String key, Bitmap bitmap) {
    if (getBitmapFromMemCache(key) == null) {
      mCache.put(key, bitmap);
    }
  }
  private static final String TAG = ThumbnailLoader.class.getSimpleName();

  private Bitmap getBitmapFromMemCache(String key) {
    return mCache.get(key);
  }

  private Object mLock = new Object();
  private boolean mIsLoadTaskRunning = false;

  private class ImageLoadTask extends AsyncTask<String, TaskItem, String> {

    private int count = 0;
    
    @Override
    protected void onPreExecute() {
      super.onPreExecute();
      mIsLoadTaskRunning = true;
      Logs.i(TAG, "start loading . task list size = " + mTaskList.size());
    }

    @Override
    protected void onPostExecute(String result) {
      super.onPostExecute(result);
      mIsLoadTaskRunning = false;
      Logs.i(TAG, "load completed , task done " + count);
    }

    @Override
    protected void onProgressUpdate(TaskItem... values) {
      super.onProgressUpdate(values);
      count++;
      String current = (String) values[0].imageview.getTag();
      if (current != null && current.equals(values[0].path)) {
        values[0].imageview
            .setImageBitmap(getBitmapFromMemCache(values[0].path));
      }else{
        Logs.i(TAG, "thumbnail pass");
      }
    }
    @Override
    protected String doInBackground(String... params) {
      while (true) {
        TaskItem item = null;
        synchronized (mLock) {
          try {
            item = mTaskList.remove(0);
          } catch (Exception e) {

          }
        }
        if (item == null) {
          break;
        }
        Bitmap bitmap = ThumbnailLoaderHelper.getImageThumbnail(new File(item.path), mContext);//(item.path);
        if(bitmap != null){
          addBitmapToMemoryCache(item.path, bitmap);
          publishProgress(item);
        }

      }
      return null;
    }

    private Bitmap getImageThumbnail(String imagePath) {
//      Bitmap bitmap = null;
//      BitmapFactory.Options options = new BitmapFactory.Options();
//      options.inJustDecodeBounds = true;
//      bitmap = BitmapFactory.decodeFile(imagePath, options);
//      options.inJustDecodeBounds = false; 
//      int h = options.outHeight;
//      int w = options.outWidth;
//      int beWidth = w / 96;
//      int beHeight = h / 96;
//      int be = 1;
//      if (beWidth < beHeight) {
//        be = beWidth;
//      } else {
//        be = beHeight;
//      }
//      if (be <= 0) {
//        be = 1;
//      }
//      Logs.i(TAG, "be = " + power(be,1));
//      options.inSampleSize = be;
//      long time = System.currentTimeMillis();
//      bitmap = BitmapFactory.decodeFile(imagePath, options);
//      Logs.i(TAG, "time  = " + (System.currentTimeMillis() - time));
//      DocumentsContract.
//      MediaStore.Images.Media.q
      //      ThumbnailUtils.e
      File file = new File(imagePath);
      return FileUtils.getThumbnail(mContext, file);
//      bitmap = ThumbnailUtils.extractThumbnail(bitmap, 96, 96);
//      return bitmap;
    }
    

  }
  
  private int power(int number,int p){
    if(number <= 1){
      return 1;
    }
    if(number < p * 2){
      return p;
    }
    return power(number, p *2);
  }

}
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