ListView控件 - 图片洗牌，而滚动 [英] ListView - Images shuffle while scrolling
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问题描述
我有两个TextViews和一个ImageView的一个ListView。这些图像都是从网上下载并LruCache被缓存。滚动时通过在ListView图像被得到混洗为几秒钟。疗法只是不应该有任何图像，直到右图像满载。我发现了一些问题，同样的问题，但没有人帮助我：/。这是我的code：
公共类NewsAdapter扩展了BaseAdapter {
私有静态LayoutInflater充气;
私人列表＆LT;项目＆GT;项目=新的LinkedList＆LT;项目＆GT;（）;
私人LruCache＆LT;字符串，位图＆GT; mMemoryCache;
公共NewsAdapter（上下文的背景下）{
充气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
//位图缓存
最终诠释maxMemory =（INT）（调用Runtime.getRuntime（）maxMemory（）/ 1024）;
最终诠释CACHESIZE = maxMemory / 8;
mMemoryCache =新LruCache＆LT;字符串，位图＆GT;（CACHESIZE）{
@覆盖
保护INT整型尺寸（字符串键，位图位图）{
返回getSizeInBytes（位）/ 1024;
}
};
}
公共无效添加（逐项）{
items.add（项目）;
}
@覆盖
公共查看getView（INT位置，查看convertView，ViewGroup中父）{
ViewHolder viewHolder =新ViewHolder（）;
如果（convertView == NULL）{
convertView = inflater.inflate（R.layout.list_item_item，NULL）;
viewHolder.ivPic =（ImageView的）convertView.findViewById（R.id.ivPic）;
viewHolder.tvTitle =（TextView中）convertView.findViewById（R.id.tvTitle）;
viewHolder.tvShortDesc =（TextView中）convertView.findViewById（R.id.tvShortDesc）;
convertView.setTag（viewHolder）;
} 其他 {
viewHolder =（ViewHolder）convertView.getTag（）;
}
最后一个项目的项目= items.get（位置）;
viewHolder.tvTitle.setText（item.getTitle（））;
viewHolder.tvShortDesc.setText（Html.fromHtml（item.getShortDesc（）））;
点阵位图= mMemoryCache.get（item.getPicUrl（））;
如果（位图！= NULL）{
viewHolder.ivPic.setImageBitmap（位）;
} 其他 {
GetBitmap GB =新GetBitmap（item.getPicUrl（），viewHolder.ivPic）;
gb.execute（）;
}
返回convertView;
}
静态类ViewHolder {
ImageView的ivPic;
TextView的tvTitle;
TextView的tvShortDesc;
}
@覆盖
公众诠释getCount将（）{
返回items.size（）;
}
@覆盖
公共项目的getItem（INT位置）{
返回items.get（位置）;
}
@覆盖
众长getItemId（INT位置）{
返回0;
}
@燮pressLint（NewApi）
公共静态INT getSizeInBytes（位图位图）{
如果（Build.VERSION.SDK_INT＆GT; = Build.VERSION_ codeS.HONEYCOMB）{
返回bitmap.getByteCount（）;
} 其他 {
返回bitmap.getRowBytes（）* bitmap.getHeight（）;
}
}
私有类GetBitmap扩展的AsyncTask＆LT;太虚，位图，位图＆GT; {
私人字符串URL;
私人ImageView的ivPic;
公共GetBitmap（字符串URL，ImageView的ivPic）{
this.url =网址;
this.ivPic = ivPic;
}
@覆盖
受保护的位图doInBackground（空... PARAMS）{
点阵位图= NULL;
尝试 {
网址URL =新的URL（this.url）;
位= BitmapFactory.de codeStream（url.openConnection（）的getInputStream（））;
}赶上（例外五）{
e.printStackTrace（）;
}
返回的位图;
}
@覆盖
保护无效onPostExecute（位图位图）{
super.onPostExecute（位）;
如果（位图！= NULL）ivPic.setImageBitmap（位）;
}
}
}
这将是很好，如果任何人有一个想法......在此先感谢！
PS：我忘了什么事，请不要提出任何库，我想这样做没有任何外部库
解决方案
公共GetBitmap（字符串URL，ImageView的ivPic，INT位置）{
this.url =网址;
this.ivPic = ivPic;
this.position =位置;
ivPic.setTag（位置）;
ivPic.setImageBitmap（空）;
}
@覆盖
保护无效onPostExecute（位图位图）{
super.onPostExecute（位）;
如果（位图=空＆安培;！及（（整数）getTag）== this.position）
ivPic.setImageBitmap（位）;
}
问题是你不检查，如果该图像是在相同的位置或没有。尝试上述code希望这将有助于。
I have a ListView with two TextViews and one ImageView. The images are loaded from the Internet and are cached by LruCache. While scrolling through the ListView the images are getting shuffled for a few seconds. Ther just shouldn't be any image until the right image is fully loaded. I found a few questions with the same problem but no one helped me :/. Here's my code:
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);
}
}
}
It would be nice if anyone has an idea... Thanks in advance!
P.S.: I forgot something, please do not suggest any libraries, I want to do it without any external library.
解决方案
public GetBitmap(String url, ImageView ivPic, int position) {
this.url = url;
this.ivPic = ivPic;
this.position = position;
ivPic.setTag(position);
ivPic.setImageBitmap(null);
}
@Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
if(bitmap != null && ((Integer)getTag) == this.position)
ivPic.setImageBitmap(bitmap);
}
Issue is you are not checking if the image is in the same position or not. Try the above code hope it will help.
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