我的应用程序有一个列表视图,列表视图的行包含imageView和Textview。应用程序从Web下载图像以在行布局中设置imageview。当我在列表视图上下来时,我遇到了关于图像重新下载的问题。出于这个原因,我使用 ViewHolder 模式来保存列表项。问题已得到解决,但这次我遇到了一个新问题。
Listview中有15行。因此,列表底部的项目不会出现。当我仔细查看列表以查看项目时,列表顶部的项目即将结束。此外,当我对列表进行清理时,列表末尾的项目将成为列表的首位。
因此它不显示需要显示的值或行。
我的getView()方法的最后一个状态是..
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.row_layout, null);
TextView programName = (TextView)convertView.findViewById(R.id.programName);
TextView programTime = (TextView)convertView.findViewById(R.id.programTime);
TextView programState = (TextView)convertView.findViewById(R.id.programState);
ImageView programImage = (ImageView)convertView.findViewById(R.id.programImage);
programName.setText(values.programNames.get(position));
programTime.setText(values.programTimes.get(position));
new imageDownload(programImage).execute(values.programImageUrls.get(position));
viewHolder = new ViewHolder();
viewHolder.p_Name = programName;
viewHolder.p_Time = programTime;
viewHolder.p_State = programState;
viewHolder.p_Image = programImage;
convertView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) convertView.getTag();
}
return convertView;
}
我的观点持有人......
public static class ViewHolder {
TextView p_Name;
TextView p_Time;
TextView p_State;
ImageView p_Image;
}
非常感谢
答案 0 :(得分:2)
将其移到您设置转换视图的位置
之外programName.setText(values.programNames.get(position));
programTime.setText(values.programTimes.get(position));
new imageDownload(programImage).execute(values.programImageUrls.get(position));
所以它看起来像这个
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.row_layout, null);
TextView programName = (TextView)convertView.findViewById(R.id.programName);
TextView programTime = (TextView)convertView.findViewById(R.id.programTime);
TextView programState = (TextView)convertView.findViewById(R.id.programState);
ImageView programImage =(ImageView)convertView.findViewById(R.id.programImage);
viewHolder = new ViewHolder();
viewHolder.p_Name = programName;
viewHolder.p_Time = programTime;
viewHolder.p_State = programState;
viewHolder.p_Image = programImage;
convertView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.p_Name.setText(values.programNames.get(position));
viewHolder.p_Time.setText(values.programTimes.get(position));
new imageDownload(programImage).execute(values.programImageUrls.get(position));
return convertView;
}
此外,我强烈建议您使用Picasso进行图像下载,因为它会自动为您处理缓存。我还会考虑用Butterknife注入你的ViewHolder,这也会减少你的代码
答案 1 :(得分:0)
感谢您的回答。我决定使用Picasso for Images。我只是改变了下面的代码
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.row_layout, null);
TextView programName = (TextView)convertView.findViewById(R.id.programName);
TextView programTime = (TextView)convertView.findViewById(R.id.programTime);
TextView programState = (TextView)convertView.findViewById(R.id.programState);
ImageView programImage =(ImageView)convertView.findViewById(R.id.programImage);
viewHolder = new ViewHolder();
viewHolder.p_Name = programName;
viewHolder.p_Time = programTime;
viewHolder.p_State = programState;
viewHolder.p_Image = programImage;
convertView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.p_Ad.setText(values.programIsimleri.get(position));
viewHolder.p_Saat.setText(values.programSaatleri.get(position));
Picasso.with(getApplicationContext()).load(values.programImageUrls.get(position)).into(viewHolder.p_Image);
return convertView;
}
代码现在正常运行。
答案 2 :(得分:-1)
您应该在ViewHolder类上有一个位置值,以便您可以从convertView.getTag()比较检索到的ViewHolder的位置。如果convertView不为null,则需要确保在视图中具有正确的信息。
if (viewHolder.position != position) {
//retrieves the correct position of the information
viewHolder.p_Name.setText(values.programNames.get(position));
//etc
viewHolder.position = position;
}