Android Open Source - bbcplayer Image Loader

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.rmgoncalo.bbcplayer;
// w  ww . ja v  a2s  . c  om
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;

public class ImageLoader {

  private static final String logtag = "ImageLoader";
  
  MemoryCache memoryCache = new MemoryCache();
  FileCache fileCache;
  ExecutorService executorService;
  private Map<ImageView, String> imageViews = Collections
      .synchronizedMap(new WeakHashMap<ImageView, String>());
  int stub_id = R.drawable.ic_launcher;

  public ImageLoader(Context context) {
    fileCache = new FileCache(context);
    executorService = Executors.newFixedThreadPool(5);
  }

  public void DisplayImage(String url, int loader, ImageView imageView) {
    
    //Log.d(logtag, url);
    
    stub_id = loader;
    imageViews.put(imageView, url);
    Bitmap bitmap = memoryCache.get(url);
    if (bitmap != null){
      imageView.setImageBitmap(bitmap);
      Log.d(logtag, "bitmap != null");
    } else {
      queuePhoto(url, imageView);
      imageView.setImageResource(loader);
    }
  }

  private void queuePhoto(String url, ImageView imageView) {
    PhotoToLoad p = new PhotoToLoad(url, imageView);
    executorService.submit(new PhotosLoader(p));
  }

  private Bitmap getBitmap(String url) {
    File f = fileCache.getFile(url);

    // from SD cache
    Bitmap b = decodeFile(f);
    if (b != null) {
      Log.d(logtag, "bitmap file != null");
      return b;
    }
    // from web
    try {
      Bitmap bitmap = null;
      URL imageUrl = new URL(url);
      HttpURLConnection conn = (HttpURLConnection) imageUrl
          .openConnection();
      conn.setConnectTimeout(30000);
      conn.setReadTimeout(30000);
      conn.setInstanceFollowRedirects(true);
      InputStream is = conn.getInputStream();
      
      Log.d(logtag, "downloading");
      
      OutputStream os = new FileOutputStream(f);
      Util.CopyStream(is, os);
      os.close();
      bitmap = decodeFile(f);
      return bitmap;
    } catch (Exception ex) {
      ex.printStackTrace();
      return null;
    }
  }

  // decodes image and scales it to reduce memory consumption
  private Bitmap decodeFile(File f) {
    try {
      // decode image size
      BitmapFactory.Options o = new BitmapFactory.Options();
      o.inJustDecodeBounds = true;
      BitmapFactory.decodeStream(new FileInputStream(f), null, o);

      // Find the correct scale value. It should be the power of 2.
      final int REQUIRED_SIZE = 70;
      int width_tmp = o.outWidth, height_tmp = o.outHeight;
      int scale = 1;
      while (true) {
        if (width_tmp / 2 < REQUIRED_SIZE
            || height_tmp / 2 < REQUIRED_SIZE)
          break;
        width_tmp /= 2;
        height_tmp /= 2;
        scale *= 2;
      }

      // decode with inSampleSize
      BitmapFactory.Options o2 = new BitmapFactory.Options();
      o2.inSampleSize = scale;
      return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {
    }
    return null;
  }

  // Task for the queue
  private class PhotoToLoad {
    public String url;
    public ImageView imageView;

    public PhotoToLoad(String u, ImageView i) {
      url = u;
      imageView = i;
    }
  }

  class PhotosLoader implements Runnable {
    PhotoToLoad photoToLoad;

    PhotosLoader(PhotoToLoad photoToLoad) {
      this.photoToLoad = photoToLoad;
    }

    @Override
    public void run() {
      if (imageViewReused(photoToLoad)){
        Log.d(logtag, "run:imageviewReused");
        return;
      }
      Bitmap bmp = getBitmap(photoToLoad.url);
      memoryCache.put(photoToLoad.url, bmp);
      
      Log.d(logtag, photoToLoad.url + "\nbmp: " + bmp.toString());
      
      if (imageViewReused(photoToLoad)){
        Log.d(logtag, "run2:imageviewReused");
        return;
      }
      BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
      Activity a = (Activity) photoToLoad.imageView.getContext();
      a.runOnUiThread(bd);
    }
  }

  boolean imageViewReused(PhotoToLoad photoToLoad) {
    String tag = imageViews.get(photoToLoad.imageView);
    if (tag == null || !tag.equals(photoToLoad.url))
      return true;
    return false;
  }

  // Used to display bitmap in the UI thread
  class BitmapDisplayer implements Runnable {
    Bitmap bitmap;
    PhotoToLoad photoToLoad;

    public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
      bitmap = b;
      photoToLoad = p;
    }

    public void run() {
      if (imageViewReused(photoToLoad))
        return;
      if (bitmap != null)
        photoToLoad.imageView.setImageBitmap(bitmap);
      else
        photoToLoad.imageView.setImageResource(stub_id);
    }
  }

  public void clearCache() {
    memoryCache.clear();
    fileCache.clear();
  }

}

Java Source Code List

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