5
Ho GridView con immagini che vengono caricate dalle miniature delle immagini della galleria. Sto caricando queste miniature da una classe in cui chiamo un metodo con l'id immagine e imageview, il metodo imposta la bitmap su imageview passata. Fino a qui funziona perfettamente ma ha fatto in modo che il thread si fermasse quando lanciavamo la vista della griglia.La cache di immagini di gridview di Android, su scroll, le immagini vengono ripetute prima di essere sostituite
Il mio problema qui è pause quando si scorre ma le immagini vengono ripetute nella vista griglia quando si scorre dall'alto verso il basso. Non sono in grado di capire il problema esatto. aiutarmi. Grazie!
Ecco come sono la creazione della pausa:
imagegrid.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView absListView, int scrollState) {
// Pause fetcher to ensure smoother scrolling when flinging
if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) {
bitmapFromId.setPauseWork(true);
} else {
bitmapFromId.setPauseWork(false);
}
}
@Override
public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
}
});
Qui è la mia vista entrare in adattatore grdiview:
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.galleryitem, null);
holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.itemCheckBox);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
ImageItem item = images.get(position);
holder.checkbox.setId(position);
holder.imageview.setId(position);
holder.checkbox.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
CheckBox cb = (CheckBox) v;
int id = cb.getId();
if (images.get(id).selection) {
cb.setChecked(false);
images.get(id).selection = false;
} else {
cb.setChecked(true);
images.get(id).selection = true;
}
}
});
holder.imageview.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
ImageItem item = images.get(id);
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
final String[] columns = { MediaStore.Images.Media.DATA };
Cursor imagecursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
columns, MediaStore.Images.Media._ID + " = " + item.id, null, MediaStore.Images.Media._ID);
if (imagecursor != null && imagecursor.getCount() > 0) {
imagecursor.moveToPosition(0);
String path = imagecursor.getString(imagecursor
.getColumnIndexOrThrow(MediaStore.Images.Media.DATA));
File file = new File(path);
imagecursor.close();
intent.setDataAndType(Uri.fromFile(file), "image/*");
startActivityForResult(intent, VIEW_IMAGE);
}
}
});
holder.imageview.setLayoutParams(mImageViewLayoutParams);
// Check the height matches our calculated column width
if (holder.imageview.getLayoutParams().height != mItemHeight) {
holder.imageview.setLayoutParams(mImageViewLayoutParams);
}
bitmapFromId.DisplayImage(item.id, holder.imageview);
// holder.imageview.setImageBitmap(item.img);
holder.checkbox.setChecked(item.selection);
return convertView;
}
La mia classe bitmap loader:
public class BitmapFromId {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
Context context;
Handler handler = new Handler();// handler to display images in UI thread
Resources mResources;
private static final int FADE_IN_TIME = 400;
private final Object mPauseLock = new Object();
private boolean mPaused = false;
public BitmapFromId(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
this.context = context;
mResources = context.getResources();
}
public void DisplayImage(long id, ImageView imageView) {
Bitmap bitmap = null;
String _id = String.valueOf(id);
imageViews.put(imageView, _id);
bitmap = memoryCache.get(_id);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(_id, imageView);
imageView.setBackgroundResource(R.drawable.empty_photo);
}
}
private void queuePhoto(String id, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(id, imageView);
executorService.submit(new PhotosLoader(p));
}
// decodes image
private Bitmap getImageFromId(String id) {
Bitmap bitmap;
long _id = Long.parseLong(id);
final String[] columns = { MediaStore.Images.Media.DATA };
final String orderBy = MediaStore.Images.Media._ID;
Cursor imagecursor = context.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns,
MediaStore.Images.Media._ID + " = " + _id + "", null, orderBy);
int count = imagecursor.getCount();
for (int i = 0; i < count; i++) {
imagecursor.moveToPosition(i);
bitmap = MediaStore.Images.Thumbnails.getThumbnail(context.getContentResolver(), _id,
MediaStore.Images.Thumbnails.MICRO_KIND, null);
return bitmap;
}
imagecursor.close();
return null;
}
// Task for the queue
private class PhotoToLoad {
public String id;
public ImageView imageView;
public PhotoToLoad(String _i, ImageView i) {
id = _i;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
@Override
public void run() {
try {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getImageFromId(photoToLoad.id);
memoryCache.put(photoToLoad.id, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
synchronized (mPauseLock) {
while (mPaused) {
try {
mPauseLock.wait();
} catch (InterruptedException e) {
}
}
}
} catch (Throwable th) {
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.id))
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) {
// Load the image fetched:
final TransitionDrawable td = new TransitionDrawable(new Drawable[] {
new ColorDrawable(android.R.color.transparent), new BitmapDrawable(mResources, bitmap) });
photoToLoad.imageView.setImageDrawable(td);
td.startTransition(FADE_IN_TIME);
} else
photoToLoad.imageView.setImageDrawable(null);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
public void setPauseWork(boolean pauseWork) {
if (pauseWork) {
synchronized (mPauseLock) {
mPaused = true;
}
} else {
synchronized (mPauseLock) {
mPaused = false;
mPauseLock.notifyAll();
}
}
}
}
https://github.com/nostra13/Android-Universal-Image-Loader –