Android Open Source - PhotoGallery Thumbnail Downloader

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From Project

Back to project page PhotoGallery.

License

The source code is released under:

MIT License

Java Source Code

package com.ambergleam.photogallery;
//w  w w . j a v a  2  s .c  om
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Message;
import android.util.Log;

public class ThumbnailDownloader<Token> extends HandlerThread {

  private static final String TAG = "TumbnailDownloader";
  private static final int MESSAGE_DOWNLOAD = 0;

  Handler mHandler;
  Map<Token, String> requestMap = Collections.synchronizedMap(new HashMap<Token, String>());
  Handler mResponseHandler;
  Listener<Token> mListener;
  
  public interface Listener<Token> {
    void onThumbnailDownloaded(Token token, Bitmap thumbnail);
  }
  
  public void setListener(Listener<Token> listener) {
    mListener = listener;
  }
  
  @SuppressLint("HandlerLeak")
  @Override
  protected void onLooperPrepared() {
    mHandler = new Handler() {
      @Override
      public void handleMessage(Message msg) {
        if (msg.what == MESSAGE_DOWNLOAD) {
          @SuppressWarnings("unchecked")
          Token token = (Token) msg.obj;
          Log.i(TAG, "Got a request for url: " + requestMap.get(token));
          handleRequest(token);
        }
      }
    };
  }

  public ThumbnailDownloader(Handler responseHandler) {
    super(TAG);
    mResponseHandler = responseHandler;
  }

  public void queueThumbnail(Token token, String url) {
    Log.i(TAG, "Got an URL: " + url);
    requestMap.put(token, url);

    mHandler.obtainMessage(MESSAGE_DOWNLOAD, token).sendToTarget();
  }

  private void handleRequest(final Token token) {
    try {
      final String url = requestMap.get(token);
      if (url == null) {
        return;
      }

      byte[] bitmapBytes = new FlickrFetchr().getUrlBytes(url);
      final Bitmap bitmap = BitmapFactory.decodeByteArray(bitmapBytes, 0, bitmapBytes.length);
      Log.i(TAG, "Bitmap created");
      
      mResponseHandler.post(new Runnable() {
        
        @Override
        public void run() {
          if (requestMap.get(token) != url) {
            return;
          }
          requestMap.remove(token);
          mListener.onThumbnailDownloaded(token, bitmap);
        }
      });
    } catch (IOException ioe) {
      Log.e(TAG, "Error downloading image", ioe);
    }
  }
  
  public void clearQueue() {
    mHandler.removeMessages(MESSAGE_DOWNLOAD);
    requestMap.clear();
  }

}

Java Source Code List

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