我一直在研究这个问题并且无法找到解决方案。我的自定义列表视图的一切似乎都正确执行。当我点击holder.feedUpVoteButton时，文字会正确更改+=1。但是，当我向下滚动并向上滚动时，文本值将恢复为单击之前的值。
我拒绝使用notifyDatasetChanged因为我没有添加任何内容或从列表中删除任何内容。
public class CustomFeedListViewAdapter extends BaseAdapter{
CustomFeedListViewAdapter customFeedListViewAdapter;
Date createdAt, currentDate; int num;
static HashMap<String, String> oneData = new HashMap<String, String>();
HashMap<String, String> iFeed = new HashMap<>();
private String likesString;
String upVoteClicked, downVoteClicked;
HashMap<String, String> mFeed = new HashMap<>();
List<ParseObject> mObjects;
private ParseObject parseObFeed;
CustomFeedListViewAdapter(Context context, ArrayList<HashMap<String, String>> data) {
super();
this.mContext = context;
GlobalFeedTab.arrayFeedList = data;
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return GlobalFeedTab.arrayFeedList.size();
}
@Override
public Object getItem(int i) {
return GlobalFeedTab.arrayFeedList.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
likes = new int[GlobalFeedTab.arrayFeedList.size()];
countryNames = new int[GlobalFeedTab.arrayFeedList.size()];
dateNames = new String[GlobalFeedTab.arrayFeedList.size()];
final ViewHolder holder;
if (view == null) {
position = i;
view = inflater.inflate(R.layout.feed_list_row, viewGroup, false);
holder = new ViewHolder();
holder.feedNumOfLikes = (TextView) view.findViewById(R.id.feedNumofLikes);
holder.feedUpVoteButton = (Button) view.findViewById(R.id.feedUpVoteButton);
} else {
position = i;
holder = (ViewHolder) view.getTag();
}
mFeed = GlobalFeedTab.arrayFeedList.get(position);
holder.feedNumOfLikes.setText(mFeed.get("likes"));
likesString = mFeed.get("likes");
likes[position] = Integer.valueOf(likesString);
holder.feedUpVoteButton.setTag(position);
ParseQuery<ParseObject> query2 = new ParseQuery<ParseObject>("FeedItem");
query2.setLimit(250);
query2.addDescendingOrder("createdAt");
query2.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(final List<ParseObject> objects, ParseException e) {
if (e == null) {
for ( final ParseObject object : objects) {
holder.feedUpVoteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int pos = (Integer) v.getTag();
parseObFeed = objects.get(pos);
username = parseObFeed.getString("username");
createdAt = parseObFeed.getDate("createdAt");
likes[pos] += 1;
parseObFeed.put("likes", likes[pos]);
holder.feedNumOfLikes.setText(String.valueOf(parseObFeed.getInt("likes")));
parseObFeed.put(ParseUser.getCurrentUser().getUsername() + "upvoteClicked", true);
parseObFeed.saveInBackground();
}
});
}
});
return view;
}
private class ViewHolder {
ImageView feedProfilePic;
TextView feedUsername;
TextView feedNumOfLikes;
TextView feedFeedItem;
TextView feedDate;
TextView feedNumofReplies;
Button feedUpVoteButton;
Button feedDownVoteButton;
Button feedCommentButton;
ListView feedListView;
}
}
答案 0 :(得分：2)
实际上这就是整个理论。当你增加一个值时。你必须在列表中从你获取数据的位置增加该值。因为当你向下滚动时，上面的行将会丢失。当你向后滚动时up，list将从列表值中再次加载。所以你要做的就是增加列表中的值，即GlobalFeedTab.arrayFeedList
this 链接有关详细信息，适用于寻求更多详细信息的任何人
当你写这一行
likes[pos] += 1;
您还必须增加你的arraylist（mFeed）中的值，然后编写notifyDataSetChanged（）;
答案 1 :(得分：1)
每次调用getView时，都会重新制作
likes = new int[GlobalFeedTab.arrayFeedList.size()];
滚动时不会保存，并且您单击的行将离开并重新进入显示。持有者可以保持这个整数值。
private class ViewHolder {
int likes;
TextView feedNumOfLikes;
}
并相应地更新
holder.feedUpVoteButton
.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
holder.feedNumOfLikes.setText(String.valueOf(++holder.likes));
但是，您还需要更新parse对象。
parseObFeed.put("likes", holder.likes);
parseObFeed.saveInBackground();
// notifyDataSetChanged(); // Up to you. Might not work without
我拒绝使用
notifyDatasetChanged因为我没有添加任何内容或从列表中删除任何内容。
您正在修改数据。调用它将使您的适配器数据与Parse Server中存储的数据一致。
修改
这变得复杂，因为你使每个“行”都有一些与它相关联的“嵌套”对象列表。我想你可以把整个清单存放在持有人手中。
private class ViewHolder {
// Java variables to hold onto
int likes;
List<ParseObject> feedItems = new ArrayList<ParseObject>();
// Android views to bind those values to
TextView feedNumOfLikes;
}
当在适配器内部时，您调用Parse来获取适配器中每个项目的辅助列表，但您只需将其存储在持有者中。 query2返回时，不要对它做任何其他事情。
你真正的问题是，query2甚至还没有回归。肯定是这是一些数据列表，但你真的想在List中显示List吗？此外，适配器的每个项目都从Parse查询完全相同的数据。我认为您需要一个过滤器...然后，您的position变量在GlobalFeedTab.arrayFeedList和List<ParseObject>之间不对应，因为它们是不同的列表。
以下是我可以指出的一些评论。
else {
holder = (ViewHolder) view.getTag();
}
// You don't need 'position', it is just the 'i' value...
mFeed = GlobalFeedTab.arrayFeedList.get(i);
// This is stored in the Activity, I guess?
likesString = mFeed.get("likes");
holder.feedNumOfLikes.setText(likesString);
holder.feedUpVoteButton.setTag(i);
ParseQuery<ParseObject> query2 = new ParseQuery<ParseObject>("FeedItem");
// This is getting some related "FeedItem" for the current row
// Just store the info, don't do anything with it yet
query2.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(final List<ParseObject> objects, ParseException e) {
if (e == null) {
holder.feedItems.clear();
holder.feedItems.addAll(objects);
notifyDataSetChanged();
}
}
};
// Here, you can setup the button for the current row
holder.feedUpVoteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int pos = (Integer) v.getTag();
// This is wrong... 'pos' is the position of the adapter! Not the index of List<ParseObject> results from earlier
// And this is a very clear ArrayIndexOutOfBounds error...
// The adapter could be shorter/longer than the holder.feedItems
parseObFeed = holder.feedItems.get(pos);
// !! TODO: Figure out which parseObFeed you actually want to use here
username = parseObFeed.getString("username");
createdAt = parseObFeed.getDate("createdAt");
holder.likes++;
parseObFeed.put("likes", holder.likes);
// This is the value that "resets" when you scroll.
// parseObFeed has not yet been saved, so when you scroll, the data isn't changed.
holder.feedNumOfLikes
.setText(String.valueOf(parseObFeed.getInt("likes")));
// Not really sure what this does - You can store an array of likes rather than one field per username
parseObFeed.put(ParseUser.getCurrentUser().getUsername() + "upvoteClicked", true);
parseObFeed.saveInBackground();
notifyDataSetChanged();
}
});
}
我不记得saveInBackground是否有回调，但这可能是值得关注的事情
答案 2 :(得分：1)
经过连续反复试验。我终于想出了如何在滚动后更改textview。我的问题是我得到了错误的ParseObject值。我的主要活动包含ParseQuery，我从likes获得了Hashmap();但是，出于某种原因，我无法直接传递喜欢的值，所以我通过了ParseObject本身。因此，我的BaseAdapter班级不需要查询。然后，我在GetView();中实现了这些代码行来回答我原来的问题：
holder.upvote[position] = holder.parseObList[position].getBoolean(ParseUser.getCurrentUser().getUsername() + "upvoteClicked");
holder.downvote[position] = holder.parseObList[position].getBoolean(ParseUser.getCurrentUser().getUsername() + "downvoteClicked");
if(holder.upvote[position] ){
holder.feedUpVoteButton.setBackgroundResource(R.drawable.arrowclicked);
holder.feedNumOfLikes.setText(String.valueOf(holder.likes[position]));
}
else if(!holder.upvote[position]){
holder.feedUpVoteButton.setBackgroundResource(R.drawable.arrowunclicked);
holder.feedNumOfLikes.setText(String.valueOf(holder.likes[position]));
}
if(holder.downvote[position]){
holder.feedDownVoteButton.setBackgroundResource(R.drawable.arrowclicked);
}
else if(!holder.downvote[position]){
holder.feedDownVoteButton.setBackgroundResource(R.drawable.arrowunclicked);
}