我正在创建一个自定义联系人应用程序..我使用ViewHolder的ArrayAdapter设计模式进行优化...由于加载缩略图图片需要很多时间,使用AsyncTask类来加载图像,对于我的屏幕中的第一组联系人,图片加载得很好,但当我向下滚动时,同一组图片随机重新循环其他联系人...我已经搜索过forumn,并找到了一些解决方案,但没有为我工作。我将我的代码如下..有人请告诉我什么是错的代码,而不是将其标记为复制QN ...Android-使用ViewHolder和AsyncTask加载联系人缩略图问题
public class CustomList extends ArrayAdapter<String>{
private final Activity context;
private final ArrayList<String> displayName,demoteValue,emergency;
ArrayList<Long> contactId;
public CustomList(Activity context,ArrayList<Long> contactId,ArrayList<String> displayName,ArrayList<String> demoteValue ,
ArrayList<String> emergency) {
super(context, R.layout.list_single, displayName);
this.context = context;
this.displayName = displayName;
this.demoteValue = demoteValue;
this.emergency = emergency;
this.contactId=contactId;
}
class MyViewHolder
{
public QuickContactBadge imageView;
public TextView txtTitle;
int position;
MyViewHolder(View v){
txtTitle = (TextView) v.findViewById(R.id.txt);
imageView = (QuickContactBadge) v.findViewById(R.id.contactimageentry);
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView=convertView;
MyViewHolder holder=null;
if(rowView==null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflater.inflate(R.layout.list_single, parent, false);
holder=new MyViewHolder(rowView);
rowView.setTag(holder);
}else{
holder= (MyViewHolder) rowView.getTag();
}
holder.txtTitle.setText(displayName.get(position));
holder.txtTitle.setPadding(5, 5, 5, 5);
//Some BLA BLA BLA work.
if(emergency.get(position).equals("1")){
holder.txtTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP,25);
holder.imageView.getLayoutParams().width=getPixels(TypedValue.COMPLEX_UNIT_DIP,50);
}
//Get and set the photo-HERE LIES THE CALL TO THE PROBLEM
holder.position = position;
new LoadContactImage(getContext(),holder,position,contactId.get(position))
.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, null);
return rowView;
}
}
这里是加载基于这些图像为我的异步任务的代码我调用它时通过的ID
public class LoadContactImage extends AsyncTask<Object, Void, Bitmap> {
private long Path;
private MyViewHolder mHolder;
private int mposition;
Context ctx;
public LoadContactImage(Context context,MyViewHolder holder,int position,Long id) {
this.mHolder= holder;
this.Path = id;
this.mposition=position;
this.ctx= context;
}
@Override
protected Bitmap doInBackground(Object... params) {
Uri my_uri = getPhotoUri(Path);
ContentResolver cr = ctx.getContentResolver();
InputStream in = null;
try {
in = cr.openInputStream(my_uri);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Bitmap bitmap = BitmapFactory.decodeStream(in);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
if (result != null && mposition == mHolder.position) {
//imv.setImageBitmap(result);
mHolder.imageView.setImageBitmap(result);
}
}
}
我在这里没有看到问题。您应该可以将holder.imageView.setImageBitmap调用到您最初在getView方法中创建持有者时的原始内容。否则,图像仍然具有旧值,直到加载完成。 –
感谢或你的回应...但我真的没有得到你的改变...你可以说明它或突出显示应该改变的代码? –
在开始加载AsyncTask之前,您应该设置holder.imageView.setImageBitmap(loadingImage),否则旧图像仍会显示,因为ListView会循环它的视图 - 在顶部滚动的那个会重新插入到底部(和其他方式)。 –