Question

我正在尝试使用ParseQueryAdapter在列表视图中显示用户名和照片。我有课程：User和Post。

我在这里设置：

String[] postsObjectIds = some_string_array

ParseQueryAdapter<Post> adapter = new ParseQueryAdapter<Post>(getActivity(), new ParseQueryAdapter.QueryFactory<Post>() {
        public ParseQuery<Post> create() {
            ParseQuery<Post> query = Post.getQuery();
            query.include("User");
            query.whereContainedIn("objectId", Arrays.asList(postsObjectIds));
            return query;
        }
});

adapter.setTextKey("username");
adapter.setImageKey("photo");
adapter.setPlaceholder(getResources().getDrawable(R.drawable.some_drawable));

ListView listView = (ListView) rootView.findViewById(R.id.post_list_view);
listView.setAdapter(adapter);

Post类有一个名为photo的列，User类有一个名为username的列。列表视图未显示用户名。

我是否必须实施自定义适配器？有快速解决方法吗？

Answer 1

我在Parse帮助论坛上找到了答案：

ParseQueryAdapter setTextKey for relational object

接受的答案是使用自定义ParseQueryAdapter<T>和Override getItemView。

例如，在我的Fragment的onCreateView方法中，我初始化了适配器并对其进行了设置（postsObjectIds是String[]}：

PostViewListViewAdapter adapter = new PostViewListViewAdapter(getActivity(), postsObjectIds);

ListView listView = (ListView) rootView.findViewById(R.id.post_list_view);
listView.setAdapter(adapter);

这是我的适配器（PostViewListViewAdapter）：

public class PostViewListViewAdapter extends ParseQueryAdapter<Post> {

    private final String[] mPostsObjectIds;

    public PostViewListViewAdapter(Context context, final String[] postsObjectIds) {
        super(context, new ParseQueryAdapter.QueryFactory<Post>(){
            public ParseQuery<Post> create() {
                ParseQuery<Post> query = Post.getQuery();
                query.include("User");

                query.whereContainedIn("objectId", Arrays.asList(postsObjectIds));
                return query;
            }
        });
        this.mPostsObjectIds = postsObjectIds;
    }

    @Override
    public View getItemView(Post post, View v, ViewGroup parent) {
        if(v == null) {
            v = View.inflate(getContext(), R.layout.list_item_post_view, null);
        }

        super.getItemView(post, v, parent);

        final TextView usernameTextView = (TextView) v.findViewById(R.id.username_text_view);

        post.getCreator().fetchIfNeededInBackground(new GetCallback<ParseUser>() {
            @Override
            public void done(ParseUser user, ParseException e) {
                usernameTextView.setText(user.getUsername());
            }
        });
        return v;
    }
}

如何使用ParseQueryAdapter从另一个类获取数据（Android + Parse）

1 个答案: