什么是实现Viewholder设计模式的最佳方式。
问题描述:
在你downvote亲切阅读之前,我已经看到已经问过的问题。许多问题与他们不符。什么是实现Viewholder设计模式的最佳方式。
这几天我更多处理自定义ListView
和自定义GridView
。我使用ViewHolder
类来平滑滚动。但是我注意到了一些奇怪的东西。当我向下滚动列表或gridView
时,项目会不断重复,当我执行ViewHolder
时,正如Android指南中推荐的那样。但是当我初始化视图时,项目不会重复。
告诉我怎样才能让这个更好。这使我平滑滚动而不重复相同的项目。
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;
}
}
此代码给我重复项,并且是推荐的方式在Android指南:
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;
}
}
private class ViewHolder { public ImageView image; public TextView title; } – Madhur