Issue with animation in image loader

Issue with animation in image loader - android

I have a ListView with rows which may have, or not, a picture. When there is a picture I start an image loader based on http://developer.android.com/resources/samples/XmlAdapters/src/com/example/android/xmladapters/ImageDownloader.html. One of my modifications is to replace the Color drawable shown while the image is loading by an animated image (a spinning wheel). In order to do that I set a spinner Bitmap in the constructor and I animate it in the download(String url, ImageView imageView) method, if the image to be downloaded is not in the cache. I clear the animation when the image is loaded and set to the ImageView.
The issue is that with the animation code
Animation rotate_picture = AnimationUtils.loadAnimation(context, R.anim.rotate_picture);
imageView.startAnimation(rotate_picture);
in the download method of my ImageDownloader, my adapter goes crazy and sometimes set the animation to downloaded images, or set the default picture to row with no picture.
When I comment these two lines everything is ok (except the spinner is not animated of course).
Anybody can help?
adapter's getView
#Override
public View getView(int position, View convertView, final ViewGroup parent) {
View row = convertView;
ItemHolder holder = null;
if(row == null)
{
LayoutInflater inflater = ((Activity)context).getLayoutInflater();
row = inflater.inflate(layoutResourceId, parent, false);
holder = new ItemHolder();
holder.title = (TextView)row.findViewById(R.id.title);
holder.date = (TextView)row.findViewById(R.id.date);
holder.desc = (EllipsizingTextView)row.findViewById(R.id.desc);
holder.pic = (ImageView)row.findViewById(R.id.pic);
row.setTag(holder);
}
else
{
holder = (ItemHolder)row.getTag();
}
Item item = data.get(position);
holder.title.setText(item.title);
holder.date.setText(Utils.UnixTime2String(item.published, "/"));
holder.desc.setMaxLines(3);
holder.desc.setText(item.descriptionintro);
if(item.list_images.size()>0){
holder.pic.setVisibility(View.VISIBLE);
imageLoader.download(GlobalData.BASE_URL + item.list_images.get(0), (ImageView) holder.pic);
}
else{
holder.pic.setVisibility(View.GONE);
holder.pic.setImageResource(0);
}
return row;
}
ImageDownloader
public class ImageDownloader {
private static final String LOG_TAG = "ImageDownloader";
private Integer xbound, ybound;
private static Context context;
private static Bitmap defaultPic;
public ImageDownloader(Context context, Bitmap defaultPic, Integer xbound, Integer ybound){
ImageDownloader.context = context;
ImageDownloader.defaultPic = defaultPic;
this.xbound = xbound;
this.ybound = ybound;
}
/**
* Download the specified image from the Internet and binds it to the provided ImageView. The
* binding is immediate if the image is found in the cache and will be done asynchronously
* otherwise. A null bitmap will be associated to the ImageView if an error occurs.
*
* #param url The URL of the image to download.
* #param imageView The ImageView to bind the downloaded image to.
*/
public void download(String url, ImageView imageView) {
resetPurgeTimer();
Bitmap bitmap = getBitmapFromCache(url);
if (bitmap == null) {
//Animation rotate_picture = AnimationUtils.loadAnimation(context, R.anim.rotate_picture);
//imageView.startAnimation(rotate_picture);
forceDownload(url, imageView);
} else {
cancelPotentialDownload(url, imageView);
imageView.setImageBitmap(bitmap);
}
}
/*
* Same as download but the image is always downloaded and the cache is not used.
* Kept private at the moment as its interest is not clear.
private void forceDownload(String url, ImageView view) {
forceDownload(url, view, null);
}
*/
/**
* Same as download but the image is always downloaded and the cache is not used.
* Kept private at the moment as its interest is not clear.
*/
private void forceDownload(String url, ImageView imageView) {
// State sanity: url is guaranteed to never be null in DownloadedDrawable and cache keys.
if (url == null) {
imageView.setImageDrawable(null);
return;
}
if (cancelPotentialDownload(url, imageView)) {
BitmapDownloaderTask task = new BitmapDownloaderTask(imageView);
DownloadedDrawable downloadedDrawable = new DownloadedDrawable(task);
imageView.setImageDrawable(downloadedDrawable);
task.execute(url);
}
}
/**
* Returns true if the current download has been canceled or if there was no download in
* progress on this image view.
* Returns false if the download in progress deals with the same url. The download is not
* stopped in that case.
*/
private static boolean cancelPotentialDownload(String url, ImageView imageView) {
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
if (bitmapDownloaderTask != null) {
String bitmapUrl = bitmapDownloaderTask.url;
if ((bitmapUrl == null) || (!bitmapUrl.equals(url))) {
bitmapDownloaderTask.cancel(true);
} else {
// The same URL is already being downloaded.
return false;
}
}
return true;
}
/**
* #param imageView Any imageView
* #return Retrieve the currently active download task (if any) associated with this imageView.
* null if there is no such task.
*/
private static BitmapDownloaderTask getBitmapDownloaderTask(ImageView imageView) {
if (imageView != null) {
Drawable drawable = imageView.getDrawable();
if (drawable instanceof DownloadedDrawable) {
DownloadedDrawable downloadedDrawable = (DownloadedDrawable)drawable;
return downloadedDrawable.getBitmapDownloaderTask();
}
}
return null;
}
Bitmap downloadBitmap(String url) {
//final int IO_BUFFER_SIZE = 4 * 1024;
final HttpClient client = new DefaultHttpClient();
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
inputStream = entity.getContent();
return BitmapFactory.decodeStream(new FlushedInputStream(inputStream), null, null);
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (IOException e) {
getRequest.abort();
} catch (IllegalStateException e) {
getRequest.abort();
} catch (Exception e) {
getRequest.abort();
}
return null;
}
/*
* Cancel and remove download task for a given ImageView. Done when going previous/next to avoid "out of memory" when clicking fast
*/
void cancelDownload(ImageView imageView){
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
if (bitmapDownloaderTask != null) {
bitmapDownloaderTask.cancel(true);
removeBitmapDownloaderTask(imageView);
}
}
private static boolean removeBitmapDownloaderTask(ImageView imageView) {
if (imageView != null) {
Drawable drawable = imageView.getDrawable();
if (drawable instanceof DownloadedDrawable) {
DownloadedDrawable downloadedDrawable = (DownloadedDrawable)drawable;
downloadedDrawable.clearBitmapDownloaderTask();
return true;
}
}
return false;
}
/*
* An InputStream that skips the exact number of bytes provided, unless it reaches EOF.
*/
static class FlushedInputStream extends FilterInputStream {
public FlushedInputStream(InputStream inputStream) {
super(inputStream);
}
#Override
public long skip(long n) throws IOException {
long totalBytesSkipped = 0L;
while (totalBytesSkipped < n) {
long bytesSkipped = in.skip(n - totalBytesSkipped);
if (bytesSkipped == 0L) {
int b = read();
if (b < 0) {
break; // we reached EOF
} else {
bytesSkipped = 1; // we read one byte
}
}
totalBytesSkipped += bytesSkipped;
}
return totalBytesSkipped;
}
}
/**
* The actual AsyncTask that will asynchronously download the image.
*/
class BitmapDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private String url;
private final WeakReference<ImageView> imageViewReference;
public BitmapDownloaderTask(ImageView imageView) {
imageViewReference = new WeakReference<ImageView>(imageView);
}
/**
* Actual download method.
*/
#Override
protected Bitmap doInBackground(String... params) {
url = params[0];
return downloadBitmap(url);
}
/**
* Once the image is downloaded, associates it to the imageView
*/
#Override
protected void onPostExecute(Bitmap bitmap) {
if (isCancelled()) {
bitmap = null;
}
if(bitmap != null ){
addBitmapToCache(url, bitmap);
if (imageViewReference != null) {
ImageView imageView = imageViewReference.get();
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
// Change bitmap only if this process is still associated with it
// Or if we don't use any bitmap to task association (NO_DOWNLOADED_DRAWABLE mode)
if (this == bitmapDownloaderTask) {
if(xbound!=null && ybound!=null){
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int xbounding = dpToPx(xbound);
int ybounding = dpToPx(ybound);
// Determine how much to scale: the dimension requiring less scaling is
// closer to the its side. This way the image always stays inside your
// bounding box AND either x/y axis touches it.
float xScale = ((float) xbounding) / width;
float yScale = ((float) ybounding) / height;
float scale = (xScale <= yScale) ? xScale : yScale;
// Create a matrix for the scaling and add the scaling data
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
// Create a new bitmap and convert it to a format understood by the ImageView
Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
width = scaledBitmap.getWidth(); // re-use
height = scaledBitmap.getHeight(); // re-use
BitmapDrawable result = new BitmapDrawable(scaledBitmap);
// Apply the scaled bitmap
imageView.setImageDrawable(result);
// Now change ImageView's dimensions to match the scaled image
//LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) imageView.getLayoutParams();
//params.width = width;
//params.height = height;
//imageView.setLayoutParams(params);
}
else{
imageView.clearAnimation();
imageView.setImageBitmap(bitmap);
}
}
}
}
}
}
private int dpToPx(int dp)
{
float density = context.getResources().getDisplayMetrics().density;
return Math.round((float)dp * density);
}
/**
* A fake Drawable that will be attached to the imageView while the download is in progress.
*
* <p>Contains a reference to the actual download task, so that a download task can be stopped
* if a new binding is required, and makes sure that only the last started download process can
* bind its result, independently of the download finish order.</p>
*/
static class DownloadedDrawable extends BitmapDrawable {
private final WeakReference<BitmapDownloaderTask> bitmapDownloaderTaskReference;
public DownloadedDrawable(BitmapDownloaderTask bitmapDownloaderTask) {
super(context.getResources(), defaultPic);
bitmapDownloaderTaskReference =
new WeakReference<BitmapDownloaderTask>(bitmapDownloaderTask);
}
public BitmapDownloaderTask getBitmapDownloaderTask() {
return bitmapDownloaderTaskReference.get();
}
public void clearBitmapDownloaderTask() {
bitmapDownloaderTaskReference.clear();
}
}
/*
*
* Image loaded listener
*
*/
OnImageDownloaderListener onImageDownloaderListener = null;
public interface OnImageDownloaderListener {
public abstract void onImageLoaded(int tag);
}
public void setOnImageDownloaderListener(OnImageDownloaderListener listener) {
onImageDownloaderListener = listener;
}
private void OnImageLoaded(int tag){
if(onImageDownloaderListener!=null) {
onImageDownloaderListener.onImageLoaded(tag);
}
}
/*
* Cache-related fields and methods.
*
* We use a hard and a soft cache. A soft reference cache is too aggressively cleared by the
* Garbage Collector.
*/
private static final int HARD_CACHE_CAPACITY = 20;
private static final int DELAY_BEFORE_PURGE = 10 * 1000; // in milliseconds
// Hard cache, with a fixed maximum capacity and a life duration
private final HashMap<String, Bitmap> sHardBitmapCache =
new LinkedHashMap<String, Bitmap>(HARD_CACHE_CAPACITY / 2, 0.75f, true) {
#Override
protected boolean removeEldestEntry(LinkedHashMap.Entry<String, Bitmap> eldest) {
if (size() > HARD_CACHE_CAPACITY) {
// Entries push-out of hard reference cache are transferred to soft reference cache
sSoftBitmapCache.put(eldest.getKey(), new SoftReference<Bitmap>(eldest.getValue()));
return true;
} else
return false;
}
};
// Soft cache for bitmaps kicked out of hard cache
private final static ConcurrentHashMap<String, SoftReference<Bitmap>> sSoftBitmapCache =
new ConcurrentHashMap<String, SoftReference<Bitmap>>(HARD_CACHE_CAPACITY / 2);
private final Handler purgeHandler = new Handler();
private final Runnable purger = new Runnable() {
public void run() {
clearCache();
}
};
/**
* Adds this bitmap to the cache.
* #param bitmap The newly downloaded bitmap.
*/
private void addBitmapToCache(String url, Bitmap bitmap) {
if (bitmap != null) {
synchronized (sHardBitmapCache) {
sHardBitmapCache.put(url, bitmap);
}
}
}
/**
* #param url The URL of the image that will be retrieved from the cache.
* #return The cached bitmap or null if it was not found.
*/
private Bitmap getBitmapFromCache(String url) {
// First try the hard reference cache
synchronized (sHardBitmapCache) {
final Bitmap bitmap = sHardBitmapCache.get(url);
if (bitmap != null) {
// Bitmap found in hard cache
// Move element to first position, so that it is removed last
sHardBitmapCache.remove(url);
sHardBitmapCache.put(url, bitmap);
return bitmap;
}
}
// Then try the soft reference cache
SoftReference<Bitmap> bitmapReference = sSoftBitmapCache.get(url);
if (bitmapReference != null) {
final Bitmap bitmap = bitmapReference.get();
if (bitmap != null) {
// Bitmap found in soft cache
return bitmap;
} else {
// Soft reference has been Garbage Collected
sSoftBitmapCache.remove(url);
}
}
return null;
}
/**
* Clears the image cache used internally to improve performance. Note that for memory
* efficiency reasons, the cache will automatically be cleared after a certain inactivity delay.
*/
public void clearCache() {
sHardBitmapCache.clear();
sSoftBitmapCache.clear();
}
/**
* Allow a new delay before the automatic cache clear is done.
*/
private void resetPurgeTimer() {
purgeHandler.removeCallbacks(purger);
purgeHandler.postDelayed(purger, DELAY_BEFORE_PURGE);
}
}

Related

List view showing images jumbled after downloading images using asynctask

I have used the async task to download the data and then showing those images in the list view I used the cache to store the images as they are repeating but not in an order. But the images gets jumbled up and sometimes they don't download. I tried searching this, but couldn't find that.
This was one of mine dream company question and i didn't clear because of this.
Please help me around.
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private static final String BASE_URL = "https://ajax.googleapis.com/ajax/services/search/images?v=1.0&q=android&start=";
private static final String IMAGE_JSON_KEY = "unescapedUrl";
private static final String RESULTS_JSON_KEY = "results";
private static final String RESPONSE_DATA_JSON_KEY = "responseData";
private int mCurrentPage;
private ListView mListView;
private Context mContext;
ArrayList<String> mImageUrls;
private LruCache<String, Bitmap> mCache;
private CustomListAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Get memory class of this device, exceeding this amount will throw an
// OutOfMemory exception.
final int memClass = ((ActivityManager) getSystemService(Context.ACTIVITY_SERVICE)).getMemoryClass();
// Use 1/8th of the available memory for this memory cache.
final int cacheSize = 1024 * 1024 * memClass / 8;
// Initialize variables
mContext = this;
mCache = new LruCache<String, Bitmap>(cacheSize) {
#Override
protected int sizeOf(String key, Bitmap value) {
// The cache size will be measured in bytes rather than number of items.
return value.getByteCount();
}
};
mListView = (ListView) findViewById(R.id.list_view);
mAdapter = new CustomListAdapter();
mImageUrls = new ArrayList<>();
// If the urls are wrong then
if (mImageUrls.isEmpty() || checkDiff()) {
fetchNewImageUrls();
}
// Set the adapter to the list view
mListView.setAdapter(mAdapter);
}
class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
private String mUrl;
public BitmapWorkerTask(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
#Override
protected Bitmap doInBackground(String... params) {
String imageUrl = params[0];
mUrl = imageUrl;
Bitmap bitmap = getBitmapFromMemCache(imageUrl);
if (bitmap == null) {
try {
URL url = new URL(imageUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
// Closing the stream after getting the sample size
InputStream inputStream = connection.getInputStream();
byte[] imageByteArray = convertToByteArray(inputStream);
bitmap = decodeSampledBitmap(imageByteArray, 200, 200);
inputStream.close();
if (bitmap != null) {
Log.d(TAG, "Image downloaded: " + imageUrl);
addBitmapToMemoryCache(imageUrl, bitmap);
} else {
Log.d(TAG, "Null Bitmap downloaded for: " + imageUrl);
}
connection.disconnect();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} else {
Log.d(TAG, "Already present in the Cache");
}
return bitmap;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = (ImageView) imageViewReference.get();
if (imageView != null && imageView.getTag().equals(mUrl)) {
imageView.setImageBitmap(bitmap);
}
}
}
}
public class CustomListAdapter extends BaseAdapter {
#Override
public int getCount() {
return mImageUrls.size();
}
#Override
public Object getItem(int position) {
return mImageUrls.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
Log.d(TAG, "Get View is called for position: " + position);
View view = convertView;
Holder holder = null;
// Holder represents the elements of the view to use
// Here are initialized
if (view == null) {
view = LayoutInflater.from(mContext).inflate(R.layout.row_item, parent, false);
holder = new Holder();
holder.mRowImage = (ImageView) view.findViewById(R.id.image_view);
holder.mRowText = (TextView) view.findViewById(R.id.row_text);
view.setTag(holder);
} else {
holder = (Holder) view.getTag();
}
// Set default image background
holder.mRowImage.setImageResource(R.drawable.ic_launcher);
// here do operations in holder variable example
holder.mRowText.setText("Image Number: " + position);
// Set the tag for the imageview
holder.mRowImage.setTag(mImageUrls.get(position));
new BitmapWorkerTask(holder.mRowImage).execute(mImageUrls.get(position));
return view;
}
}
public static class Holder {
TextView mRowText;
ImageView mRowImage;
}
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mCache.put(key, bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
return (Bitmap) mCache.get(key);
}
public Bitmap decodeSampledBitmap(byte[] imageByteArray, int reqWidth, int reqHeight) {
Bitmap bm = null;
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
bm = BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length, options);
return bm;
}
public int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = Math.round((float) height / (float) reqHeight);
} else {
inSampleSize = Math.round((float) width / (float) reqWidth);
}
}
Log.d(TAG, "Sample size is: " + inSampleSize);
return inSampleSize;
}
private void fetchNewImageUrls() {
new AsyncTask<String, Void, Boolean>() {
#Override
protected Boolean doInBackground(String... params) {
try {
StringBuilder response = new StringBuilder();
URL url = new URL(params[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null)
response.append(inputLine);
in.close();
connection.disconnect();
String resp = response.toString();
Log.d(TAG, "Response is: " + response);
// Parsing the response
JSONObject jsonObject = new JSONObject(resp);
JSONObject jsonObject1 = jsonObject.getJSONObject(RESPONSE_DATA_JSON_KEY);
JSONArray jsonArray = jsonObject1.getJSONArray(RESULTS_JSON_KEY);
for (int i = 0; i < 4; i++) {
JSONObject dataObject = jsonArray.getJSONObject(i);
mImageUrls.add(dataObject.getString(IMAGE_JSON_KEY));
}
mCurrentPage++;
Log.d(TAG, "Number of image urls are: " + mImageUrls.size());
return true;
} catch (JSONException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
#Override
protected void onPostExecute(Boolean value) {
super.onPostExecute(value);
if (checkDiff() && value) {
Log.d(TAG, "Again fetching the Images");
fetchNewImageUrls();
}
if (!value) {
Log.d(TAG, "Error while getting the response");
}
mAdapter.notifyDataSetChanged();
}
}.execute(BASE_URL + mCurrentPage);
}
private boolean checkDiff() {
int diff = mImageUrls.size() - mCurrentPage * 4;
Log.d(TAG, "Diff is: " + diff);
return diff < 8;
}
public static byte[] convertToByteArray(InputStream input) {
byte[] buffer = new byte[8192];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
try {
while ((bytesRead = input.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
} catch (IOException e) {
e.printStackTrace();
}
return output.toByteArray();
}
}

Since you do not cancel the unfinished "out of view" downloads these may interfere with your gui.
Example
listview line1 shows item#1 with has an async task to download image "a" not completed yet
scroll down, line1 is now invisible;
listview line8 becomes visible recycling item#1 new async task to download image "x"
async task to download image "a" finishes displaying wrong image. Line8 shows image "a" instead of "x"
to solve this you have to cancel the pending unnecessary unfinished async task-s
public static class Holder {
ImageView mRowImage;
String mImageUrl;
// neccessary to cancel unfinished download
BitmapWorkerTask mDownloader;
}
static class BitmapWorkerTask extends AsyncTask<Holder, Void, Bitmap> {
Holder mHolder;
protected Bitmap doInBackground(Holder... holders) {
mHolder = holders[0];
...
}
protected void onPostExecute(...) {
mHolder.mDownloader = null;
if (!isCancelled()) {
this.mHolder.mRowImage.setImageBitmap(image);
}
this.mHolder = null;
}
}
public class CustomListAdapter extends BaseAdapter {
#Override
public View getView(int position, ...) {
...
if (view == null) {
holder = ...
...
} else {
holder = (Holder) view.getTag();
}
...
// cancel unfinished mDownloader
if (holder.mDownloader != null) {
holder.mDownloader.cancel(false);
holder.mDownloader = null;
}
holder.mImageUrl = mImageUrls.get(position);
holder.mDownloader = new BitmapWorkerTask()
holder.mDownloader.execute(holder);
}
}
Here is a working example for this combination of Adapter + Holder + AsyncTask
[Update]
Potential problems with this solution.
Most modern android versions execute only one async task at a time. If you are fetching the images via the web you cannot download multible images at the same time. See running-parallel-asynctask#stackoverflow for details.
There may be promlems with configuration change(like orientation). See #Selvin-s comment below. I have posted this question "what-happens-with-view-references-in-unfinished-asynctask-after-orientation-chan#stackoverflow" to find out more about it.

Load large Bitmaps

I have two following methods those load my Bitmaps. And when I've tried to load huge image 2000px x 6000px I've got UIfreeze for about 3 seconds. Can anubody help me to improve loading speed of huge images? I's important for me on screen orientation change, because these methods always have been called by that lib and my UI always freezes for about 3 second before rotate...
/**
* Async task used to get image details
*/
private static class TilesInitTask implements Runnable {
private final WeakReference<ScaleImageView> viewRef;
private final WeakReference<Context> contextRef;
private final WeakReference<DecoderFactory<? extends ImageRegionDecoder>> decoderFactoryRef;
private final Uri source;
private ImageRegionDecoder decoder;
private Exception exception;
public TilesInitTask(ScaleImageView view, Context context, DecoderFactory<? extends ImageRegionDecoder> decoderFactory, Uri source) {
this.viewRef = new WeakReference<>(view);
this.contextRef = new WeakReference<>(context);
this.decoderFactoryRef = new WeakReference<DecoderFactory<? extends ImageRegionDecoder>>(decoderFactory);
this.source = source;
}
public void run() {
ScaleImageView view = null;
try {
String sourceUri = source.toString();
Context context = contextRef.get();
DecoderFactory<? extends ImageRegionDecoder> decoderFactory = decoderFactoryRef.get();
view = viewRef.get();
if (context != null && decoderFactory != null && view != null) {
decoder = decoderFactory.make();
Point dimensions = decoder.init(context, source);
int sWidth = dimensions.x;
int sHeight = dimensions.y;
int exifOrientation = view.getExifOrientation(sourceUri);
if (view.sRegion != null) {
sWidth = view.sRegion.width();
sHeight = view.sRegion.height();
}
view.onTilesInited(decoder, sWidth, sHeight, exifOrientation);
}
} catch (Exception e) {
Log.e(TAG, "Failed to initialise bitmap decoder", e);
this.exception = e;
if (view != null && view.onImageEventListener != null) {
view.onImageEventListener.onImageLoadError(exception);
}
}
}
}
/**
* Called by worker task when decoder is ready and image size and EXIF orientation is known.
*/
private synchronized void onTilesInited(ImageRegionDecoder decoder, int sWidth, int sHeight, int sOrientation) {
// If actual dimensions don't match the declared size, reset everything.
if (this.sWidth > 0 && this.sHeight > 0 && (this.sWidth != sWidth || this.sHeight != sHeight)) {
reset(false);
if (bitmap != null) {
if (!bitmapIsCached) {
bitmap.recycle();
}
bitmap = null;
bitmapIsPreview = false;
bitmapIsCached = false;
}
}
this.decoder = decoder;
this.sWidth = sWidth;
this.sHeight = sHeight;
this.sOrientation = sOrientation;
checkReady();
checkImageLoaded();
invalidate();
requestLayout();
}
/**
* Async task used to load images
*/
private static class TileLoadTask implements Runnable {
private final WeakReference<ScaleImageView> viewRef;
private final WeakReference<ImageRegionDecoder> decoderRef;
private final WeakReference<Tile> tileRef;
private Exception exception;
public TileLoadTask(ScaleImageView view, ImageRegionDecoder decoder, Tile tile) {
this.viewRef = new WeakReference<>(view);
this.decoderRef = new WeakReference<>(decoder);
this.tileRef = new WeakReference<>(tile);
tile.loading = true;
}
public void run() {
ScaleImageView view = null;
try {
view = viewRef.get();
ImageRegionDecoder decoder = decoderRef.get();
Tile tile = tileRef.get();
if (decoder != null && tile != null && view != null && decoder.isReady()) {
synchronized (view.decoderLock) {
// Update tile's file sRect according to rotation
view.fileSRect(tile.sRect, tile.fileSRect);
if (view.sRegion != null) {
tile.fileSRect.offset(view.sRegion.left, view.sRegion.top);
}
tile.bitmap = decoder.decodeRegion(tile.fileSRect, tile.sampleSize);
tile.loading = false;
view.onTileLoaded();
}
} else if (tile != null) {
tile.loading = false;
}
} catch (Exception e) {
Log.e(TAG, "Failed to decode tile", e);
this.exception = e;
if (view != null && view.onImageEventListener != null) {
view.onImageEventListener.onTileLoadError(exception);
}
}
}
}
/**
* Called by worker task when a tile has loaded. Redraws the view.
*/
private synchronized void onTileLoaded() {
checkReady();
checkImageLoaded();
if (isBaseLayerReady() && bitmap != null) {
if (!bitmapIsCached) {
bitmap.recycle();
}
bitmap = null;
bitmapIsPreview = false;
bitmapIsCached = false;
}
invalidate();
}

Working with bitmaps and pictures is a sensitive operation. I suggest you to use a library for these kind of operations suces as
https://github.com/nostra13/Android-Universal-Image-Loader
http://square.github.io/picasso/
Edit:
Here you can how to add and init library.
Correct usage of Universal Image Loader
After you init with best configuration you can use file paths below which is suitable for your operation:
"http://example.com/image.png" // from Web
"file:///mnt/sdcard/image.png" // from SD card
"file:///mnt/sdcard/video.mp4" // from SD card (video thumbnail)
"content://media/external/images/media/13" // from content provider
"content://media/external/video/media/13" // from content provider (video thumbnail)
"assets://image.png" // from assets
"drawable://" + R.drawable.img // from drawables (non-9patch images)
And finally you can load it with:
ImageLoader imageLoader = ImageLoader.getInstance(); // Get singleton instance
imageLoader.displayImage(imageUri, imageView);
Good luck.

Android outofmemory bitmap

I have used the following animation class because i have multiple images to make an animation. After the 7th animation i get OutofMemoryError. androidgraphics.Bitmap.createBitmap
public class AnimationsContainer {
public int FPS = 30; // animation FPS
// single instance procedures
private static AnimationsContainer mInstance;
private AnimationsContainer() {
};
public static AnimationsContainer getInstance() {
if (mInstance == null)
mInstance = new AnimationsContainer();
return mInstance;
}
// animation progress dialog frames
private int[] mProgressAnimFrames = {};
// animation splash screen frames
/**
* #param imageView
* #return progress dialog animation
*/
public FramesSequenceAnimation createProgressDialogAnim(ImageView imageView) {
return new FramesSequenceAnimation(imageView, mProgressAnimFrames);
}
/**
* #param imageView
* #return splash screen animation
*/
public FramesSequenceAnimation createSplashAnim(ImageView imageView, int[] n) {
return new FramesSequenceAnimation(imageView, n);
}
/**
* AnimationPlayer. Plays animation frames sequence in loop
*/
public class FramesSequenceAnimation {
private int[] mFrames; // animation frames
private int mIndex; // current frame
private boolean mShouldRun; // true if the animation should continue running. Used to stop the animation
private boolean mIsRunning; // true if the animation currently running. prevents starting the animation twice
private SoftReference<ImageView> mSoftReferenceImageView; // Used to prevent holding ImageView when it should be dead.
private Handler mHandler;
private int mDelayMillis;
private OnAnimationStoppedListener mOnAnimationStoppedListener;
private Bitmap mBitmap = null;
private BitmapFactory.Options mBitmapOptions;
public FramesSequenceAnimation(ImageView imageView, int[] frames) {
mHandler = new Handler();
mFrames = frames;
mIndex = -1;
mSoftReferenceImageView = new SoftReference<ImageView>(imageView);
mShouldRun = false;
mIsRunning = false;
mDelayMillis = 50;
imageView.setImageResource(mFrames[0]);
// use in place bitmap to save GC work (when animation images are the same size & type)
if (Build.VERSION.SDK_INT >= 11) {
Bitmap bmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
int width = bmp.getWidth();
int height = bmp.getHeight();
Bitmap.Config config = bmp.getConfig();
mBitmap = Bitmap.createBitmap(width, height, config);
mBitmapOptions = new BitmapFactory.Options();
// setup bitmap reuse options.
mBitmapOptions.inBitmap = mBitmap;
mBitmapOptions.inMutable = true;
mBitmapOptions.inSampleSize = 1;
}
}
private int getNext() {
mIndex++;
if (mIndex == mFrames.length){
mIndex = mIndex - 1;
mShouldRun = false;
}
return mFrames[mIndex];
}
/**
* Starts the animation
*/
public synchronized void start() {
mShouldRun = true;
if (mIsRunning)
return;
Runnable runnable = new Runnable() {
#Override
public void run() {
ImageView imageView = mSoftReferenceImageView.get();
if (!mShouldRun || imageView == null) {
mIsRunning = false;
if (mOnAnimationStoppedListener != null) {
mOnAnimationStoppedListener.onAnimationStopped();
}
return;
}
mIsRunning = true;
mHandler.postDelayed(this, mDelayMillis);
if (imageView.isShown()) {
int imageRes = getNext();
if (mBitmap != null) { // so Build.VERSION.SDK_INT >= 11
Bitmap bitmap = null;
try {
bitmap = BitmapFactory.decodeResource(imageView.getResources(), imageRes, mBitmapOptions);
} catch (Exception e) {
e.printStackTrace();
}
if (bitmap != null) {
imageView.setImageBitmap(bitmap);
} else {
imageView.setImageResource(imageRes);
mBitmap.recycle();
mBitmap = null;
}
} else {
imageView.setImageResource(imageRes);
}
}
}
};
mHandler.post(runnable);
}
/**
* Stops the animation
*/
public synchronized void stop() {
mShouldRun = false;
}
}
}
Can anyone explain me why and tell me how to fix it? I already added
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
to my manifest file.

It might help to be sure that you are not keeping references to unneeded images. This is happening because you probably have the "standard" memory heap of 32MB or something similar (maybe 64MB or maybe 16MB). If you consider that most images are 5MB or more, it's not surprising you are out of memory.
You can increase the heap size using android:largeHeap="true" like this:
How to increase heap size of an android application?

Example using Androids lrucache

I need help understanding androids LruCache. I want to use to load images into my gridview in order make the loading/scrolling better. Can someone post an example code using LruCache please. Thanks in advance.

Below is a class I made for using LruCache, this is based on the presentation Doing More With Less: Being a Good Android Citizen given at Google I/O 2012.
Check out the movie for more information about what I'm doing in the TCImageLoader class:
public class TCImageLoader implements ComponentCallbacks2 {
private TCLruCache cache;
public TCImageLoader(Context context) {
ActivityManager am = (ActivityManager) context.getSystemService(
Context.ACTIVITY_SERVICE);
int maxKb = am.getMemoryClass() * 1024;
int limitKb = maxKb / 8; // 1/8th of total ram
cache = new TCLruCache(limitKb);
}
public void display(String url, ImageView imageview, int defaultresource) {
imageview.setImageResource(defaultresource);
Bitmap image = cache.get(url);
if (image != null) {
imageview.setImageBitmap(image);
}
else {
new SetImageTask(imageview).execute(url);
}
}
private class TCLruCache extends LruCache<String, Bitmap> {
public TCLruCache(int maxSize) {
super(maxSize);
}
#Override
protected int sizeOf(ImagePoolKey key, Bitmap value) {
int kbOfBitmap = value.getByteCount() / 1024;
return kbOfBitmap;
}
}
private class SetImageTask extends AsyncTask<String, Void, Integer> {
private ImageView imageview;
private Bitmap bmp;
public SetImageTask(ImageView imageview) {
this.imageview = imageview;
}
#Override
protected Integer doInBackground(String... params) {
String url = params[0];
try {
bmp = getBitmapFromURL(url);
if (bmp != null) {
cache.put(url, bmp);
}
else {
return 0;
}
} catch (Exception e) {
e.printStackTrace();
return 0;
}
return 1;
}
#Override
protected void onPostExecute(Integer result) {
if (result == 1) {
imageview.setImageBitmap(bmp);
}
super.onPostExecute(result);
}
private Bitmap getBitmapFromURL(String src) {
try {
URL url = new URL(src);
HttpURLConnection connection
= (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
return myBitmap;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
}
#Override
public void onLowMemory() {
}
#Override
public void onTrimMemory(int level) {
if (level >= TRIM_MEMORY_MODERATE) {
cache.evictAll();
}
else if (level >= TRIM_MEMORY_BACKGROUND) {
cache.trimToSize(cache.size() / 2);
}
}
}

I've found a really easy way that work perfectly for me...
This is the Cache.java class. In this class, the static getInstance() method enables us to create only one cache instance in the whole application. getLru() method is used to retrieve the cached object, it will be shown later how to use it. This cache is generic, meaning you can save any Object type into it. The cache memory size here is set to 1024. It can be changed if it is too small:
import android.support.v4.util.LruCache;
public class Cache {
private static Cache instance;
private LruCache<Object, Object> lru;
private Cache() {
lru = new LruCache<Object, Object>(1024);
}
public static Cache getInstance() {
if (instance == null) {
instance = new Cache();
}
return instance;
}
public LruCache<Object, Object> getLru() {
return lru;
}
}
This is the code in your activity where you save the bitmap to the cache:
public void saveBitmapToCahche(){
//The imageView that you want to save it's bitmap image resourse
ImageView imageView = (ImageView) findViewById(R.id.imageViewID);
//To get the bitmap from the imageView
Bitmap bitmap = ((BitmapDrawable)imageview.getDrawable()).getBitmap();
//Saving bitmap to cache. it will later be retrieved using the bitmap_image key
Cache.getInstance().getLru().put("bitmap_image", bitmap);
}
This is the code where you retrieve the bitmap from the cache, then set an imageView to this bitmap:
public void retrieveBitmapFromCache(){
//The imageView that you want to set to the retrieved bitmap
ImageView imageView = (ImageView) findViewById(R.id.imageViewID);
//To get bitmap from cache using the key. Must cast retrieved cache Object to Bitmap
Bitmap bitmap = (Bitmap)Cache.getInstance().getLru().get("bitmap_image");
//Setting imageView to retrieved bitmap from cache
imageView.setImageBitmap(bitmap));
}
THAT'S ALL! As you can see this is rather easy and simple.
EXAMPLE:
In my application, All the views are saved in class variables so they can be seen by all the methods in the class. In my first activity, I save the image bitmap to the cache in an onClickButton() method, right before I start a new activity using intent. I also save a string value in my cache:
public void onClickButton(View v){
Bitmap bitmap = ((BitmapDrawable)imageView.getDrawable()).getBitmap();
String name = textEdit.getText().toString();
Cache.getInstance().getLru().put("bitmap_image", bitmap);
Cache.getInstance().getLru().put("name", name);
Intent i = new Intent(FirstActivity.this, SecondActivity.class);
startActivity(i);
}
Then I navigate from the second activity to a third activity also using intents. In the last activity I save other objects into my cache, then go back to the first activity using an intent. Once I'm back in the first activity, the onCreate() method will start. In that method, I check if my cache has any bitmap value or any String value separately (based on my application business):
public ImageView imageView;
public EditText editText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_first);
//...Other code...
//The imageView that you want to save it's bitmap image resourse
imageView = (ImageView) findViewById(R.id.imageViewID);
//The editText that I want to save it's text into cache
editText = (EditText)findViewById(R.id.editTextID);
if(Cache.getInstance().getLru().get("name")!=null){
editText.setText(Cache.getInstance().getLru().get("name").toString());
}
if(Cache.getInstance().getLru().get("bitmap_image")!=null){
imageView.setImageBitmap((Bitmap)Cache.getInstance().getLru().get("bitmap_image"));
}
//...Other code...
}

Take a look at Caching Bitmaps where the use of LruCache is demonstrated.
The relevant portion of the code from the page is as follows:-
private LruCache mMemoryCache;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
// Get memory class of this device, exceeding this amount will throw an
// OutOfMemory exception.
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;
mMemoryCache = new LruCache(cacheSize) {
#Override
protected int sizeOf(String key, Bitmap bitmap) {
// The cache size will be measured in bytes rather than number of items.
return bitmap.getByteCount();
}
};
...
}
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mMemoryCache.put(key, bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
return mMemoryCache.get(key);
}

https://techienotes.info/2015/08/28/caching-bitmaps-in-android-using-lrucache/
This link has a full project having sample application to load images into Gridview using LruCache.
This class is using LruCache and taken from the code given in the link
public class ImageAdapter extends BaseAdapter{
private String TAG = getClass().getSimpleName();
Context mContext;
ArrayList<Uri> imageList;
private LruCache<String, Bitmap> mLruCache;
public ImageAdapter (Context context){
mContext = context;
//Find out maximum memory available to application
//1024 is used because LruCache constructor takes int in kilobytes
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
// Use 1/4th of the available memory for this memory cache.
final int cacheSize = maxMemory / 4;
Log.d(TAG, "max memory " + maxMemory + " cache size " + cacheSize);
// LruCache takes key-value pair in constructor
// key is the string to refer bitmap
// value is the stored bitmap
mLruCache = new LruCache<String, Bitmap>(cacheSize) {
#Override
protected int sizeOf(String key, Bitmap bitmap) {
// The cache size will be measured in kilobytes
return bitmap.getByteCount() / 1024;
}
};
imageList = new ArrayList<Uri>();
//Change this directory to where the images are stored
String imagesFolderPath = Environment.getExternalStorageDirectory().getPath()+"/backups/";
File imageSrcDir = new File (imagesFolderPath);
// if directory not present, build it
if (!imageSrcDir.exists()){
imageSrcDir.mkdirs();
}
ArrayList<File> imagesInDir = getImagesFromDirectory(imageSrcDir);
for (File file: imagesInDir){
// imageList will hold Uri of all images
imageList.add(Uri.fromFile(file));
}
}
#Override
public int getCount() {
return imageList.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return 0;
}
/**
*
* #param position The position of the item within the
* adapter's data set of the item whose view we want.
* #param convertView it is the view to be reused
* #param parent The parent that this view will eventually be attached to
* #return a View corresponding to the data at the specified position.
*/
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
Bitmap thumbnailImage = null;
if (convertView == null){
imageView = new ImageView(mContext);
imageView.setLayoutParams(
//150,150 is size of imageview to display image
new GridView.LayoutParams(150, 150));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
else {
imageView = (ImageView)convertView;
}
// Use the path as the key to LruCache
final String imageKey = imageList.get(position).toString();
//thumbnailImage is fetched from LRU cache
thumbnailImage = getBitmapFromMemCache(imageKey);
if (thumbnailImage == null){
// if asked thumbnail is not present it will be put into cache
BitmapWorkerTask task = new BitmapWorkerTask(imageView);
task.execute(imageKey);
}
imageView.setImageBitmap(thumbnailImage);
return imageView;
}
/**
* This function returns the files from a directory
* #param parentDirPath source directory in which images are located
* #return list of Files
*/
private ArrayList<File> getImagesFromDirectory (File parentDirPath){
ArrayList <File> listOfImages = new ArrayList<File>();
File [] fileArray = null;
if ( parentDirPath.isDirectory() ){//parentDirPath.exists() &&
// &&
// parentDirPath.canRead()){
fileArray = parentDirPath.listFiles();
}
if (fileArray == null){
return listOfImages; // return empty list
}
for (File file: fileArray){
if (file.isDirectory()){
listOfImages.addAll(getImagesFromDirectory(file));
}
else {
// Only JPEG and PNG formats are included
// for sake of simplicity
if (file.getName().endsWith("png") ||
file.getName().endsWith("jpg")){
listOfImages.add(file);
}
}
}
return listOfImages;
}
/**
* This function will return the scaled version of original image.
* Loading original images into thumbnail is wastage of computation
* and hence we will take put scaled version.
*/
private Bitmap getScaledImage (String imagePath){
Bitmap bitmap = null;
Uri imageUri = Uri.parse (imagePath);
try{
BitmapFactory.Options options = new BitmapFactory.Options();
/**
* inSampleSize flag if set to a value > 1,
* requests the decoder to sub-sample the original image,
* returning a smaller image to save memory.
* This is a much faster operation as decoder just reads
* every n-th pixel from given image, and thus
* providing a smaller scaled image.
* 'n' is the value set in inSampleSize
* which would be a power of 2 which is downside
* of this technique.
*/
options.inSampleSize = 4;
options.inScaled = true;
InputStream inputStream = mContext.getContentResolver().openInputStream(imageUri);
bitmap = BitmapFactory.decodeStream(inputStream, null, options);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return bitmap;
}
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mLruCache.put(key, bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
return mLruCache.get(key);
}
class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
public BitmapWorkerTask(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
#Override
protected Bitmap doInBackground(String... params) {
final Bitmap bitmap = getScaledImage(params[0]);
addBitmapToMemoryCache(String.valueOf(params[0]), bitmap);
return bitmap;
}
// onPostExecute() sets the bitmap fetched by doInBackground();
#Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = (ImageView)imageViewReference.get();
if (imageView != null) {
imageView.setImageBitmap(bitmap);
}
}
}
}
}

Utility Class to save and retrieve Bitmap from own Cache.
package com.roomco.android.utils;
import android.graphics.Bitmap;
import android.support.v4.util.LruCache;
public class MyCache {
private static MyCache instance;
private LruCache<Object, Object> lru;
private MyCache() {
lru = new LruCache<Object, Object>(1024);
}
public static MyCache getInstance() {
if (instance == null) {
instance = new MyCache();
}
return instance;
}
public LruCache<Object, Object> getLru() {
return lru;
}
public void saveBitmapToCahche(String key, Bitmap bitmap){
MyCache.getInstance().getLru().put(key, bitmap);
}
public Bitmap retrieveBitmapFromCache(String key){
Bitmap bitmap = (Bitmap)MyCache.getInstance().getLru().get(key);
return bitmap;
}
}
Usage:
//Save bitmap in cache
MyCache.getInstance().saveBitmapToCahche("your_key",bitmap);
// Get bitmap from cache
MyCache.getInstance().retrieveBitmapFromCache("your_key");

Android List view update

I am struggling to update a list view with data from a database, this works nicely by using a SimpleCursorAdapter. But the image view on the rows is not updated on the activity start, I have to scroll through the list a few times and only then the images are loaded in the image view.
This is the binder i am using for the SimpleCursorAdapter:
private class PromotionViewBinder implements SimpleCursorAdapter.ViewBinder {
private int done;
public boolean setViewValue(View view, Cursor cursor, int index) {
Log.e(""+cursor.getCount(),"");
View tmpview = view;
if (index == cursor.getColumnIndex(PromotionsTable.SEEN_COL)) {
boolean read = cursor.getInt(index) > 0 ? true : false;
TextView title = (TextView) tmpview;
if (!read) {
title.setTypeface(Typeface.DEFAULT_BOLD, 0);
} else {
title.setTypeface(Typeface.DEFAULT);
}
return true;
} else if (tmpview.getId() == R.id.promotions_list_row_image){
String imageURL = cursor.getString(index);
Log.e("",imageURL);
imageRetriever.displayImage(imageURL, (ImageView)tmpview);
return true;
} else {
return false;
}
}
}
The image retriever class is the LazyList example from here. As you will see this is using a runnable to retrieve the images and once the task is done is automatically updating the given imageView...Do you think that the reference to the imageView is lost somewhere on the way?
Thanx in advance,
Nick
package com.tipgain.promotions;
The image retriever class:
/**
* This class is used for retrieving images from a given web link. it uses local
* storage and memory to store the images. Once a image is downloaded
* successfully the UI gets updated automatically.
*
*
*/
public class ImageRetriever {
private final String TAG = ImageRetriever.class.getName();
private MemoryImageCache memoryImgCache = new MemoryImageCache();
private LocalStorageImageCache localFileCache;
private Map<ImageView, String> imageViewHolders = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
private ExecutorService execService;
final int defaultImageID = R.drawable.photo_not_available;
public ImageRetriever(Context context) {
localFileCache = new LocalStorageImageCache(context);
execService = Executors.newFixedThreadPool(5);
}
public void displayImage(String url, ImageView imageView) {
imageViewHolders.put(imageView, url);
Bitmap bmp = memoryImgCache.retrieve(url);
if (bmp != null) {
Log.e("case 1", " " + (bmp != null));
imageView.setImageBitmap(bmp);
} else {
Log.e("case 2", " " + (bmp == null));
addImageToQueue(url, imageView);
imageView.setImageResource(defaultImageID);
}
}
private void addImageToQueue(String url, ImageView imageView) {
NextImageToLoad img = new NextImageToLoad(url, imageView);
execService.submit(new ImagesRetriever(img));
}
/**
* This method is used for retrieving the Bitmap Image.
*
* #param url
* String representing the url pointing to the image.
* #return Bitmap representing the image
*/
private Bitmap getBitmap(String url) {
File imageFile = localFileCache.getFile(url);
// trying to get the bitmap from the local storage first
Bitmap bmp = decodeImageFile(imageFile);
if (bmp != null)
return bmp;
// if the file was not found locally we retrieve it from the web
try {
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(imageFile);
Utils.CopyStream(is, os);
os.close();
bmp = decodeImageFile(imageFile);
return bmp;
} catch (MalformedURLException e) {
Log.e(TAG, e.getMessage());
} catch (FileNotFoundException e) {
Log.e(TAG, e.getMessage());
} catch (IOException e) {
Log.e(TAG, e.getMessage());
}
return null;
}
/**
* This method is used for decoding a given image file. Also, to reduce
* memory, the image is also scaled.
*
* #param imageFile
* #return
*/
private Bitmap decodeImageFile(File imageFile) {
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(imageFile), null,
options);
// Find the correct scale value. It should be the power of 2.
// Deciding the perfect scaling value. (^2).
final int REQUIRED_SIZE = 100;
int tmpWidth = options.outWidth, tmpHeight = options.outHeight;
int scale = 1;
while (true) {
if (tmpWidth / 2 < REQUIRED_SIZE
|| tmpHeight / 2 < REQUIRED_SIZE)
break;
tmpWidth /= 2;
tmpHeight /= 2;
scale *= 2;
}
// decoding using inSampleSize
BitmapFactory.Options option2 = new BitmapFactory.Options();
option2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(imageFile),
null, option2);
} catch (FileNotFoundException e) {
Log.e(TAG, e.getLocalizedMessage());
}
return null;
}
private boolean reusedImage(NextImageToLoad image) {
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
String tag = imageViewHolders.get(image.imageView);
if ((tag == null) || (!tag.equals(image.url)))
return true;
return false;
}
/**
* Clears the Memory and Local cache
*/
public void clearCache() {
memoryImgCache.clear();
localFileCache.clear();
}
/**
* This class implements a runnable that is used for updating the promotions
* images on the UI
*
*
*/
class UIupdater implements Runnable {
Bitmap bmp;
NextImageToLoad image;
public UIupdater(Bitmap bmp, NextImageToLoad image) {
this.bmp = bmp;
this.image = image;
Log.e("", "ui updater");
}
public void run() {
Log.e("ui updater", "ui updater");
if (reusedImage(image))
return;
Log.e("nick", "" + (bmp == null) + " chberugv");
if (bmp != null){
image.imageView.setImageBitmap(bmp);
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}else
image.imageView.setImageResource(defaultImageID);
}
}
private class ImagesRetriever implements Runnable {
NextImageToLoad image;
ImagesRetriever(NextImageToLoad image) {
this.image = image;
}
public void run() {
Log.e("images retirever", " images retriever");
if (reusedImage(image))
return;
Bitmap bmp = getBitmap(image.url);
memoryImgCache.insert(image.url, bmp);
if (reusedImage(image))
return;
UIupdater uiUpdater = new UIupdater(bmp, image);
Activity activity = (Activity) image.imageView.getContext();
activity.runOnUiThread(uiUpdater);
//Context c = image.imageView.getContext();
//c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}
}
/**
* This class encapsulates the image being downloaded.
*
* #author Nicolae Anca
*
*/
private class NextImageToLoad {
public String url;
public ImageView imageView;
public NextImageToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
}
Modified Runnable:
class UIupdater implements Runnable {
Bitmap bmp;
NextImageToLoad image;
public UIupdater(Bitmap bmp, NextImageToLoad image) {
this.bmp = bmp;
this.image = image;
}
public void run() {
if (reusedImage(image))
return;
if (bmp != null){
image.imageView.setImageBitmap(bmp);
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}else
image.imageView.setImageResource(defaultImageID);
}
}

Thats an interesting way to do what you are doing. Have you tried extending the Simple Cursor Adapter?
What you do is implement a ViewHolder and put your imageview in it.
Then in your ImageRetriever, write a Listener which will be called once the image is ready and retrieved.
Implement this listener in the Viewholder.
You create the view in getView() and request for the image in BindView().
Once the image gets loaded, the list will be refreshed automatically.

one way to do it is by calling notifyDataSetChenged on listview, and another was is to have adapter as member variable and when something changes on listview you call a function that assigns new listadapter to member adapter. That way your list will be redraw on change.

I guess, you have to use some handler, calling after image load, which will call notifyDataSetChanged for list adapter

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