在列表视图中加载图像无法正常工作

Question

我正在加载不同的图像到我的listview中的每一行，我已经看过几个教程，并观看了最佳实践的谷歌视频，但它仍然无法使用正常。我的列表视图项目最终显示幻灯片中的所有图像，当我滚动列表时它们也会发生变化。

我正在使用Universal Image Loader来下载和缓存我的图像。这是我的整个班级的代码。我似乎无法得到这个工作。

public class EventAdapter extends ArrayAdapter<EventDetails>{ 

private Context context; 
LayoutInflater inflater; 
LinkedList<EventDetails> event_details; 
ImageView event_imge; 
ViewHolder holder; 
public ImageLoader imageLoader; 


public EventAdapter(Context mcontext, 
     LinkedList<EventDetails> m_event_details) { 
    super(mcontext, R.layout.event_list_row, m_event_details); 

    this.context = mcontext; 
    this.event_details = new LinkedList<EventDetails>(); 
    this.event_details = m_event_details; 
} 

public View getView(int position, View myview, ViewGroup parent) { 

    View v = myview; 

    if (inflater == null) { 
     inflater = (LayoutInflater) context 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 

    if (v == null) { 
     v = inflater.inflate(R.layout.event_list_row, parent, 
       false); 
     imageLoader = ImageLoader.getInstance(); 
     holder = new ViewHolder(); 
     holder.event_name = (TextView) v.findViewById(R.id.event_name); 
     holder.event_show = (TextView) v.findViewById(R.id.event_show); 
     holder.event_time = (TextView) v.findViewById(R.id.event_time); 
     holder.event_date = (TextView) v.findViewById(R.id.event_date); 
     holder.event_genre = (TextView) v.findViewById(R.id.event_genre); 
     holder.event_price = (TextView) v.findViewById(R.id.event_price); 
     holder.img = (ImageView) v.findViewById(R.id.event_image); 
     holder.event_ll = (LinearLayout) v.findViewById(R.id.event_frame_ll); 

     v.setTag(holder); 
    }else{ 
     holder = (ViewHolder) v.getTag(); 
    } 

    final EventDetails eD = event_details.get(position); 
    if(eD != null){ 
     holder.event_name.setText(eD.name.toUpperCase()); 
     holder.event_show.setText(eD.show.toUpperCase()); 
     holder.event_time.setText(eD.time.toUpperCase()); 
     holder.event_date.setText(eD.date.toUpperCase()); 
     holder.event_price.setText("£"+String.format("%.2f", eD.price)); 
     holder.event_genre.setText(eD.genre.toUpperCase()); 

     if(eD.isStandBy == 0){ 
      holder.event_ll.setVisibility(View.GONE); 
     }else{ 
      holder.event_ll.setVisibility(View.VISIBLE); 
     } 

     holder.img.setTag(eD.image_url[0]); 
     if(MemoryCacheUtil.findCachedBitmapsForImageUri(eD.image_url[0], ImageLoader.getInstance().getMemoryCache()).size() > 0){ 
      //holder.img.setBackgroundDrawable(new BitmapDrawable(MemoryCacheUtil.findCachedBitmapsForImageUri(eD.image_url[0], ImageLoader.getInstance().getMemoryCache()).get(0))); 
      holder.img.setImageBitmap(MemoryCacheUtil.findCachedBitmapsForImageUri(event_details.get(position).image_url[0], ImageLoader.getInstance().getMemoryCache()).get(0)); 

     }else{    
      DisplayImageOptions options = new DisplayImageOptions.Builder().cacheInMemory(true).build(); 
      ImageLoader.getInstance().loadImage(eD.image_url[0], options, new SimpleImageLoadingListener() {        

       @Override 
       public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) { 
        //holder.img.setBackgroundDrawable(new BitmapDrawable(loadedImage)); 
        holder.img.setImageBitmap(loadedImage); 
       } 
      }); 
     } 
    }  

    return v; 
} 

static class ViewHolder{ 

    TextView event_name; 
    TextView event_show; 
    TextView event_time; 
    TextView event_date; 
    TextView event_genre; 
    TextView event_price; 
    ImageView img; 
    LinearLayout event_ll; 
} 

Answer 1

您的holder是一个类变量。因此，只有一个持有者的实例被附加到您的每个再循环视图中。这应该工作。

此外，请勿使用LinkedList来存储项目。 LinkedList的访问时间为O(n)。改为使用ArrayList。

public View getView(int position, View myview, ViewGroup parent) { 
    ViewHolder holder; 

    View v = myview; 

    if (inflater == null) { 
     inflater = (LayoutInflater) context 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 

    if (v == null) { 
     v = inflater.inflate(R.layout.event_list_row, parent, 
       false); 

     imageLoader = ImageLoader.getInstance(); 
     holder = new ViewHolder(); 
     holder.event_name = (TextView) v.findViewById(R.id.event_name); 
     holder.event_show = (TextView) v.findViewById(R.id.event_show); 
     holder.event_time = (TextView) v.findViewById(R.id.event_time); 
     holder.event_date = (TextView) v.findViewById(R.id.event_date); 
     holder.event_genre = (TextView) v.findViewById(R.id.event_genre); 
     holder.event_price = (TextView) v.findViewById(R.id.event_price); 
     holder.img = (ImageView) v.findViewById(R.id.event_image); 
     holder.event_ll = (LinearLayout) v.findViewById(R.id.event_frame_ll); 

     v.setTag(holder); 
    }else{ 
     holder = (ViewHolder) v.getTag(); 
    } 

    final EventDetails eD = event_details.get(position); 
    if(eD != null){ 
     holder.event_name.setText(eD.name.toUpperCase()); 
     holder.event_show.setText(eD.show.toUpperCase()); 
     holder.event_time.setText(eD.time.toUpperCase()); 
     holder.event_date.setText(eD.date.toUpperCase()); 
     holder.event_price.setText("£"+String.format("%.2f", eD.price)); 
     holder.event_genre.setText(eD.genre.toUpperCase()); 

     if(eD.isStandBy == 0){ 
      holder.event_ll.setVisibility(View.GONE); 
     }else{ 
      holder.event_ll.setVisibility(View.VISIBLE); 
     } 

     holder.img.setTag(eD.image_url[0]); 
     if(MemoryCacheUtil.findCachedBitmapsForImageUri(eD.image_url[0], ImageLoader.getInstance().getMemoryCache()).size() > 0){ 
      //holder.img.setBackgroundDrawable(new BitmapDrawable(MemoryCacheUtil.findCachedBitmapsForImageUri(eD.image_url[0], ImageLoader.getInstance().getMemoryCache()).get(0))); 
      holder.img.setImageBitmap(MemoryCacheUtil.findCachedBitmapsForImageUri(event_details.get(position).image_url[0], ImageLoader.getInstance().getMemoryCache()).get(0)); 

     }else{    
      DisplayImageOptions options = new DisplayImageOptions.Builder().cacheInMemory(true).build(); 
      ImageLoader.getInstance().loadImage(eD.image_url[0], options, new SimpleImageLoadingListener() {        

       @Override 
       public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) { 
        //holder.img.setBackgroundDrawable(new BitmapDrawable(loadedImage)); 
        holder.img.setImageBitmap(loadedImage); 
       } 
      }); 
     } 
    }  

    return v; 
}