Question

我在RecyclerView Adapter中使用SortedList，我想知道在我更改Adapter中的数据后，RecyclerView何时完成了更新（并调用了正确的方法，例如notifyItemRangeChanged）。有没有办法做到这一点？

我的问题是我需要在过滤其内容后将RecyclerView滚动到顶部。我从我的适配器上调用Activity方法来过滤其成员上的项目。之后，我只是在RecyclerView上调用scrollToPosition（0）并且它并不总是按预期工作，尤其是当列表上的更改操作仅为1项后。

以下是我在适配器上调用的更新方法代码：

private SortedList<Game> games;
private ArrayList<Game> allGames;

public void search(String query) {
    replaceAll(filterGames(query));
}

public void replaceAll(Collection<Game> games) {
    this.games.beginBatchedUpdates();
    List<Game> gamesToRemove = new ArrayList<>();
    for (int i = 0; i < this.games.size(); i++) {
        Game game = this.games.get(i);
        if (!games.contains(game)) {
            gamesToRemove.add(game);
        }
    }
    for (Game game : gamesToRemove) {
        this.games.remove(game);
    }
    this.games.addAll(games);
    this.games.endBatchedUpdates();
}

private Collection<Game> filterGames(String query) {
    query = query.toLowerCase();
    List<Game> filteredGames = new ArrayList<>();
    for (Game game : allGames) {
        String gameTitle = game.getTitle().toLowerCase();
        if (gameTitle.contains(query)) {
            filteredGames.add(game);
        }
    }
    return filteredGames;
}

以下是我如何从Activity中调用它：

private RecyclerView gamesList;
private GameAdapter gamesAdapter;

@Override
public boolean onQueryTextChange(String newText) {
    gamesAdapter.search(newText);
    gamesList.scrollToPosition(0);
    return false;
}

Answer 1

您可以使用RecyclerAdapter.registerAdapterDataObserver(RecyclerView.AdapterDataObserver observer)

收听已更改的观点：

extends LayoutManager then override onItemUpdated(RecyclerView recyclerView, int positionStart, int itemCount, Object payload)

Answer 2

尝试使用，

recyclerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    //At this point the layout is complete and the 
                    //dimensions of recyclerView and any child views are known.
                }
            });

Answer 3

您可以为此使用add_action( 'plugins_loaded', 'pine_scripts' );。

Answer 4

您与this相关的问题接缝。

我尝试了这个，对我有用。这是Kotlin扩展名

fun RecyclerView.runWhenReady(action: () -> Unit) {
    val globalLayoutListener = object: ViewTreeObserver.OnGlobalLayoutListener {
        override fun onGlobalLayout() {
            action()
            viewTreeObserver.removeOnGlobalLayoutListener(this)
        }
    }
    viewTreeObserver.addOnGlobalLayoutListener(globalLayoutListener)
}

然后称呼它

myRecyclerView.runWhenReady {
    // Your action
}

如何找出RecyclerView已完成更新？

4 个答案: