android 关于ListView Item数据混乱问题

这个问题关系到一个软件的成败,为什么这么说呢?因为ListView是andriod主要的展示数据的方式,所以我们用的最多的也就是ListView.而如果ListView有问题,那不就是最大的问题.

今天讲的这个问题是关于ListView数据混乱的问题.问题是这样的,数据已经展示在了ListView上的时候,当我们拉动ListView.每个Item项的数据会变动.如下图:

这是没有拖动时的数据.当我拖动ListView时,变成了如下图:

数据在变来变去.

想了很久也不知道在哪里出了问题,最后经理终于发现了我的问题.问题有三点:

第一.

我的ViewHolder写的有问题.如下:

private class ViewHodler

{

public static TextView t_Subject;

public static TextView t_Author;

public static TextView t_Dateline;

public static ImageView t_photo;

public static TextView t_Replies;

}

我将ViewHodler里的每个属性都设置成了static.

static,说明只用一个内存空间,而getView时,每个Item的数据不一样,所以不能用static 

第二.

没有重置ViewHodler.

if (convertView == null)

{

LayoutInflater inflater = getLayoutInflater();

convertView = inflater.inflate(R.layout.m_digesttopiclist_item,

null);

hodler = new ViewHodler();

hodler.t_Subject = (TextView) convertView

.findViewById(R.m_digesttopicid.subject);

hodler.t_Author = (TextView) convertView

.findViewById(R.m_digesttopicid.author);

hodler.t_Dateline = (TextView) convertView

.findViewById(R.m_digesttopicid.dateline);

hodler.t_photo = (ImageView) convertView

.findViewById(R.m_digesttopicid.userimage);

hodler.t_Replies = (TextView) convertView

.findViewById(R.m_digesttopicid.replies);

hodler.t_photo.setTag(oAuthorphoto);

convertView.setTag(hodler);

}else {

hodler = (ViewHodler) convertView.getTag();

resetViewHolder(hodler);

}

protected void resetViewHolder(ViewHodler p_ViewHolder)

{

p_ViewHolder.t_Subject.setText(null);

p_ViewHolder.t_Author.setText(null);

p_ViewHolder.t_Dateline.setText(null);

p_ViewHolder.t_photo.setImageDrawable(null);

p_ViewHolder.t_Replies.setText(null);

}

第三.

头像没有绑定tag

@Override

public View getView(int position, View convertView, ViewGroup parent)

{

ViewHodler hodler = null;

String oTid =null;

String oSubject = null;

String oAuthor = null;

String oDateline = null;

String oReplies = null;

String odateStr = null;

String oAuthorphoto=null;

try

{

ExtJSONObject oDigestItem  = mForumJsonArray.getExtJSONObject(position);

oTid = oDigestItem.getString("tid");

oSubject = oDigestItem.getString("subject");

oAuthor = oDigestItem.getString("author");

oDateline =oDigestItem.getString("dateline");

odateStr = AppUtility.formatRelativeTime(Integer

.parseInt(oDateline));

Log.i("TAG", "date= " + oDateline);

oReplies = oDigestItem.getString("replies");

oAuthorphoto=oDigestItem.getString("authorid");

}

catch (JSONException e)

{

e.printStackTrace();

}

if (convertView == null)

{

LayoutInflater inflater = getLayoutInflater();

convertView = inflater.inflate(R.layout.m_digesttopiclist_item,

null);

hodler = new ViewHodler();

hodler.t_Subject = (TextView) convertView

.findViewById(R.m_digesttopicid.subject);

hodler.t_Author = (TextView) convertView

.findViewById(R.m_digesttopicid.author);

hodler.t_Dateline = (TextView) convertView

.findViewById(R.m_digesttopicid.dateline);

hodler.t_photo = (ImageView) convertView

.findViewById(R.m_digesttopicid.userimage);

hodler.t_Replies = (TextView) convertView

.findViewById(R.m_digesttopicid.replies);

hodler.t_photo.setTag(oAuthorphoto);

convertView.setTag(hodler);

}else {

hodler = (ViewHodler) convertView.getTag();

resetViewHolder(hodler);

}

hodler.t_Subject.setText(oSubject);

hodler.t_Dateline.setText(odateStr);

hodler.t_Author.setText(oAuthor);

hodler.t_Replies.setText(oReplies);

hodler.t_Replies.setGravity(Gravity.CENTER);

hodler.t_photo.setTag(oTid);

String userFaceUrl=AppUtility.getResourceString(R.string.apiuserphotourl)+"uid="+oAuthorphoto+"&size=middle";

this.setImageValue(hodler.t_photo,oTid,userFaceUrl,100, 100, R.drawable.m_newestlistimage,-1);

return convertView;

}

文章转自：http://blog.sina.com.cn/s/blog_629b701e0100y7dn.html