/**
* checks whether a previous task is loading the same url
*
* @param url url of the image to be fetched
* @param oldTask task that might already fetching an image, might be null
* @return true if there is no other concurrent task running
*/
private boolean checkConcurrentTasks(String url, LoaderTask oldTask) {
if (oldTask == null || (!url.equals(oldTask.getUrl()))) {
oldTask.cancel(true);
} else {
// task != null && url == task.getUrl
// there is already a concurrent task fetching the image
return false;
}
return true;
}
@Override
public void load(ImageView imageView) {
ImageWrapper w = new ImageWrapper(imageView);
if (w.getUrl() == null) {
Log.w("ImageLoader", "You should never call load if you don't set a ImageTag on the view");
return;
}
if (checkConcurrentTasks(w.getUrl(), w.getLoaderTask())) {
// only continue if a concurrent task has not yet been started
try {
// get bitmap from cache
Bitmap b = loaderContext.getCache().get(w.getUrl(), w.getHeight(), w.getWidth());
if (b != null && !b.isRecycled()) {
w.setBitmap(b);
return;
}
// get preview or loading image
String thumbUrl = w.getPreviewUrl();
if (thumbUrl != null) {
b = loaderContext.getCache().get(thumbUrl, w.getPreviewHeight(), w.getPreviewWidth());
if (b != null && !b.isRecycled()) {
w.setBitmap(b);
} else {
setResource(w, w.getLoadingResourceId());
}
} else {
setResource(w, w.getLoadingResourceId());
}
if (w.isUseCacheOnly()) {
return;
}
// spin off a new task for this url
LoaderTask task = new LoaderTask(imageView, loaderContext);
w.setLoaderTask(task);
task.execute();
} catch (ImageNotFoundException inf) {
setResource(w, w.getNotFoundResourceId());
} catch (Throwable t) {
setResource(w, w.getNotFoundResourceId());
}
}
}