我有一个ListView,其中包含两个TextView和一个ImageView。这些图像是从互联网加载的,并且由LruCache进行缓存。当滚动ListView时,图像会在几秒钟内被混淆。直到正确的图像完全加载之前,不应该有任何图像显示。我找到了一些具有相同问题的问题,但没有人帮助我 :/.这是我的代码:
public class NewsAdapter extends BaseAdapter {
private static LayoutInflater inflater;
private List<Item> items = new LinkedList<Item>();
private LruCache<String, Bitmap> mMemoryCache;
public NewsAdapter(Context context) {
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// Bitmap Cache
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
final int cacheSize = maxMemory / 8;
mMemoryCache = new LruCache<String, Bitmap>(cacheSize) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
return getSizeInBytes(bitmap) / 1024;
}
};
}
public void add(Item item) {
items.add(item);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = new ViewHolder();
if(convertView == null) {
convertView = inflater.inflate(R.layout.list_item_item, null);
viewHolder.ivPic = (ImageView) convertView.findViewById(R.id.ivPic);
viewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);
viewHolder.tvShortDesc = (TextView) convertView.findViewById(R.id.tvShortDesc);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
final Item item = items.get(position);
viewHolder.tvTitle.setText(item.getTitle());
viewHolder.tvShortDesc.setText(Html.fromHtml(item.getShortDesc()));
Bitmap bitmap = mMemoryCache.get(item.getPicUrl());
if (bitmap != null) {
viewHolder.ivPic.setImageBitmap(bitmap);
} else {
GetBitmap gb = new GetBitmap(item.getPicUrl(), viewHolder.ivPic);
gb.execute();
}
return convertView;
}
static class ViewHolder {
ImageView ivPic;
TextView tvTitle;
TextView tvShortDesc;
}
@Override
public int getCount() {
return items.size();
}
@Override
public Item getItem(int position) {
return items.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@SuppressLint("NewApi")
public static int getSizeInBytes(Bitmap bitmap) {
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
return bitmap.getByteCount();
} else {
return bitmap.getRowBytes() * bitmap.getHeight();
}
}
private class GetBitmap extends AsyncTask<Void, Bitmap, Bitmap> {
private String url;
private ImageView ivPic;
public GetBitmap(String url, ImageView ivPic) {
this.url = url;
this.ivPic = ivPic;
}
@Override
protected Bitmap doInBackground(Void... params) {
Bitmap bitmap = null;
try {
URL url = new URL(this.url);
bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
@Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
if (bitmap != null) ivPic.setImageBitmap(bitmap);
}
}
}
如果有人有想法,那就太好了...提前谢谢!
P.S.: 我忘了一件事,请不要建议任何库,我想在没有任何外部库的情况下完成它。