BitmapDecodeWorkerTask.java

package de.danoeh.antennapodsp.asynctask;

import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.TransitionDrawable;
import android.os.Handler;
import android.util.Log;
import android.widget.ImageView;
import de.danoeh.antennapodsp.AppConfig;
import de.danoeh.antennapodsp.PodcastApp;
import de.danoeh.antennapodsp.R;
import de.danoeh.antennapodsp.asynctask.ImageLoader.ImageWorkerTaskResource;
import de.danoeh.antennapodsp.util.BitmapDecoder;

public class BitmapDecodeWorkerTask extends Thread {

    protected int PREFERRED_LENGTH;
    public static final int FADE_DURATION = 500;

    /**
     * Can be thumbnail or cover
     */
    protected int imageType;

    private static final String TAG = "BitmapDecodeWorkerTask";
    private ImageView target;
    protected CachedBitmap cBitmap;

    protected ImageLoader.ImageWorkerTaskResource imageResource;

    private Handler handler;

    private final int defaultCoverResource;

    public BitmapDecodeWorkerTask(Handler handler, ImageView target,
                                  ImageWorkerTaskResource imageResource, int length, int imageType) {
        super();
        this.handler = handler;
        this.target = target;
        this.imageResource = imageResource;
        this.PREFERRED_LENGTH = length;
        this.imageType = imageType;
        this.defaultCoverResource = android.R.color.transparent;
    }

    /**
     * Should return true if tag of the imageview is still the same it was
     * before the bitmap was decoded
     */
    protected boolean tagsMatching(ImageView target) {
        Object tag = target.getTag(R.id.imageloader_key);
        return tag != null && tag.equals(imageResource.getImageLoaderCacheKey());
    }

    protected void onPostExecute() {
        // check if imageview is still supposed to display this image
        if (tagsMatching(target) && cBitmap.getBitmap() != null) {
            Drawable[] drawables = new Drawable[]{
                    PodcastApp.getInstance().getResources().getDrawable(android.R.color.transparent),
                    new BitmapDrawable(PodcastApp.getInstance().getResources(), cBitmap.getBitmap())
            };
            TransitionDrawable transitionDrawable = new TransitionDrawable(drawables);
            target.setImageDrawable(transitionDrawable);
            transitionDrawable.startTransition(FADE_DURATION);
        } else {
            if (AppConfig.DEBUG)
                Log.d(TAG, "Not displaying image");
        }
    }

    @Override
    public void run() {
        cBitmap = new CachedBitmap(BitmapDecoder.decodeBitmapFromWorkerTaskResource(
                PREFERRED_LENGTH, imageResource), PREFERRED_LENGTH);
        if (cBitmap.getBitmap() != null) {
            storeBitmapInCache(cBitmap);
        } else {
            Log.w(TAG, "Could not load bitmap. Using default image.");
            cBitmap = new CachedBitmap(BitmapFactory.decodeResource(
                    target.getResources(), defaultCoverResource),
                    PREFERRED_LENGTH);
        }
        if (AppConfig.DEBUG)
            Log.d(TAG, "Finished loading bitmaps");

        endBackgroundTask();
    }

    protected final void endBackgroundTask() {
        handler.post(new Runnable() {

            @Override
            public void run() {
                onPostExecute();
            }

        });
    }

    protected void onInvalidStream() {
        cBitmap = new CachedBitmap(BitmapFactory.decodeResource(
                target.getResources(), defaultCoverResource), PREFERRED_LENGTH);
    }

    protected void storeBitmapInCache(CachedBitmap cb) {
        ImageLoader loader = ImageLoader.getInstance();
        if (imageType == ImageLoader.IMAGE_TYPE_COVER) {
            loader.addBitmapToCoverCache(imageResource.getImageLoaderCacheKey(), cb);
        } else if (imageType == ImageLoader.IMAGE_TYPE_THUMBNAIL) {
            loader.addBitmapToThumbnailCache(imageResource.getImageLoaderCacheKey(), cb);
        }
    }

}