Question

我正在使用ExpandableListView和自定义适配器，并且正在调用一个方法来重置我的适配器中的对象列表。我从异步任务传递该列表，该任务从API检索数据。当我检查适配器方法中新传递的列表时，它显示列表大小为零。在传递之前的asynctask它不是。发生了什么？在异步中：

protected void onPostExecute(String result) {
        try {
            JsonObject jo = new JsonParser().parse(result).getAsJsonObject();
            JsonArray jsonArray = jo.getAsJsonArray("data");
            Log.e("array:", jsonArray.toString());
            Gson gson = new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd hh:mm:ss.S")
                    .create();
            Post[] posts = gson.fromJson(jsonArray, Post[].class);
            offset = offset + posts.length;
            if(posts.length<limit)
                completed = true;
            for(Post p : posts) {
                postList.add(p);
                Log.e("Post:", p.toString());
            }
            expandableListAdapter.setPosts(postList);
            expandableListAdapter.notifyDataSetChanged();
            loading = false;
        }
        catch (Exception e) {
            Log.e("In PostExecute of Home", "exception: ", e);
        }

适配器：

public class ExpandableListAdapter extends BaseExpandableListAdapter {
    private Context context;
    private List<Post> posts;

    public void setPosts(List<Post> p ){
        this.posts.clear();
        this.posts.addAll(p);
        Log.e(":size",String.valueOf(p.size()));

    }
    public ExpandableListAdapter(Context context, List<Post> posts) {
        this.context = context;
        this.posts = posts;
    }

    @Override
    public void registerDataSetObserver(DataSetObserver observer) {
        super.registerDataSetObserver(observer);
    }
    @Override
    public Comment getChild(int groupPosition, int childPosititon) {
        Post post = posts.get(groupPosition);
        if (post.getCommentList().size() > childPosititon) {
            return post.getCommentList().get(childPosititon);
        }
        return null;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public View getChildView(int groupPosition, final int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {
        Comment comment = getChild(groupPosition, childPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.activity_home_comment, null);
        }
        TextView commentView = (TextView) convertView.findViewById(R.id.commentV);
        commentView.setText(comment.toString());
        return convertView;

    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this.posts.get(groupPosition).getCommentList().size();
    }

    @Override
    public Post getGroup(int groupPosition) {
        return this.posts.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        return this.posts.size();
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        Post post = this.posts.get(groupPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.activity_home_post, null);
        }
        TextView postView = (TextView) convertView.findViewById(R.id.post);
        postView.setTypeface(Typeface.create("sans-serif-light", Typeface.NORMAL));
        postView.setText(post.getText());
        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    public void updateReceiptsList (List<Post> postList) {
        this.posts.clear();
        this.posts.addAll(postList);
        Log.e(":size",String.valueOf(postList.size()));
        Log.e("checking", postList.toString());
        for(Post p: postList) {
            Log.e("post", p.toString());
        }
        this.notifyDataSetChanged();
        Log.e("checking", "here");

    }
}

Answer 1

此适配器丢失对您的列表的引用。 notifyDataSetChanged（）将不起作用。

expandableListAdapter = ExpandableListAdapter（context，postList）; expandableListAdapter.notifyDataSetChanged（）;

请再读一遍。

notifydatasetchange-not-working-from-custom-adapter

arrayadapter-notifydatasetchanged-is-not-working

可扩展列表视图，数据不刷新

1 个答案: