什么是实现Viewholder设计模式的最佳方法. [英] What is best way to implement Viewholder design pattern.

问题描述

在您不赞成投票之前，我已经看过已经问过的问题.许多问题与他们不符.

Before you downvote kindly read I have seen already asked questions. Many problem doesn't match with them.

这些天，我更多地处理自定义ListView和自定义GridView.我使用ViewHolder类进行平滑滚动.但是我注意到了一些奇怪的事情.当我向下滚动列表或实现ViewHolder时按gridView时，项目会不断重复，这在Android指南中是推荐的.但是当我从中初始化视图时，项目不会重复.

These days I am more dealing with a custom ListView and custom GridView. I use the ViewHolder class for smooth scrolling. But there is something weird I have noticed. Items keep repeating when I scroll down the list or gridView when I implement ViewHolder, as it is recommended in Android guides. But when I initialize views out of it, items don't repeat.

告诉我如何使它变得更好.这使我可以平滑滚动，而无需重复相同的项目.

Tell me how I can make this better. This gives me smooth scrolling without repeating the same items.

public class GridAdapter extends BaseAdapter {
    Context context;
    Main values;
    LayoutInflater inflater;
    public GridAdapter(Context context, Main main){
        this.context=context;
        this.values=main;
        inflater = ( LayoutInflater )context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return values.getPosts().size();
    }

    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        ImageLoader imageLoader= ImageLoader.getInstance();
        ViewHolder viewHolder = null;
        if(convertView==null){
            viewHolder = new ViewHolder();
            convertView = inflater.inflate(R.layout.grid_item,parent,false);

            convertView.setTag(viewHolder);
        }
        else {
            viewHolder=(ViewHolder)convertView.getTag();
        }
        viewHolder.image=(ImageView)convertView.findViewById(R.id.thumbnail);
        viewHolder.title=(TextView)convertView.findViewById(R.id.title);
        viewHolder.title.setText(Html.fromHtml(values.getPosts().get(position).getTitle()));
        imageLoader.displayImage(values.getPosts().get(position).getThumbnail_images().getFull().getUrl(), viewHolder.image);
        return convertView;
    }

    private static class ViewHolder{
        public static ImageView image;
        public static TextView title;
    }
}

此代码可让我重复项目，这是Android指南中推荐的方式:

This code gives me repeating items and is the recommended way in Android guides:

public class GridAdapter extends BaseAdapter {
Context context;
Main values;
LayoutInflater inflater;
public GridAdapter(Context context, Main main){
    this.context=context;
    this.values=main;
    inflater = ( LayoutInflater )context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
    return values.getPosts().size();
}

@Override
public Object getItem(int position) {
    return position;
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ImageLoader imageLoader= ImageLoader.getInstance();
    ViewHolder viewHolder = null;
    if(convertView==null){
        viewHolder = new ViewHolder();
        convertView = inflater.inflate(R.layout.grid_item,parent,false);
    viewHolder.image=(ImageView)convertView.findViewById(R.id.thumbnail);
    viewHolder.title=(TextView)convertView.findViewById(R.id.title);
        convertView.setTag(viewHolder);
    }
    else {
        viewHolder=(ViewHolder)convertView.getTag();
    }

    viewHolder.title.setText(Html.fromHtml(values.getPosts().get(position).getTitle()));
    imageLoader.displayImage(values.getPosts().get(position).getThumbnail_images().getFull().getUrl(), viewHolder.image);
    return convertView;
}

private static class ViewHolder{
    public static ImageView image;
    public static TextView title;
}
}

推荐答案

 public static ImageView image;
 public static TextView title;

是错误的.他们应该是

public ImageView image;
public TextView title;

没有static.这应该可以解决您的问题.您可以在此处

without static . This should fix your issue. You can read more about static keyword here

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