我的RecyclerView适配器变得有点忙。这就是我要做的事，但到目前为止还没有成功。当用户单击弹出菜单时，如果匹配不是当前活动的匹配，则会显示2个选项（编辑，删除）。当用户选择编辑时，我将其设为当前匹配，但我也想将其移动到recyclerview的顶部。我试过这个：
Collections.swap（mMatches，0，position）; notifyItemMoved（position，0）;
但没有成功。我能做什么？代码如下：
public class MatchItemAdapter extends RecyclerView.Adapter<MatchItemAdapter.ViewHolder> {
private List<Match> mMatches;
private final Context mContext;
public MatchItemAdapter(Context context, List<Match> items) {
this.mContext = context;
this.mMatches = items;
}
@Override
public MatchItemAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(mContext);
View itemView = inflater.inflate(R.layout.list_item_match, parent, false);
ViewHolder viewHolder = new ViewHolder(itemView);
return viewHolder;
}
@Override
public void onBindViewHolder(final MatchItemAdapter.ViewHolder holder, final int position) {
final Match match = mMatches.get(position);
holder.matchIsActive = false;
final Match globalMatch = GlobalMatch.getMatch();
try {
holder.tvName.setText(match.getMatchName());
holder.tvDate.setText(match.getMatchDate());
holder.imageView.findViewById(R.id.imageView);
holder.hiddenMatchId.setText(match.getMatchId());
holder.container.findViewById(R.id.list_item_container);
Typeface bold = Typeface.create("san-serif", Typeface.BOLD);
String itemMatchId = holder.hiddenMatchId.getText().toString();
if (itemMatchId.equals(globalMatch.getMatchId())) {
holder.tvName.setTypeface(bold);
holder.container.setBackgroundColor(Color.parseColor("#a4a4a4"));
holder.tvName.setTextSize(24);
holder.matchIsActive = true;
}
holder.imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
final PopupMenu popup = new PopupMenu(view.getContext(), holder.imageView);
if (!holder.matchIsActive) {
popup.getMenuInflater().inflate(R.menu.popup_menu, popup.getMenu());
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
switch (item.getItemId()) {
case R.id.edit_match:
GlobalMatch.changeMatch(match); // make this match the current match
// place a string representation of the current match in SharedPreferences
String jsonString = MatchHelper.jsonStringFromMatch(holder.imageView.getContext(), match);
SharedPreferences.Editor editor = holder.itemView.getContext().getSharedPreferences(
MY_GLOBAL_PREFS, holder.itemView.getContext().MODE_PRIVATE).edit();
editor.putString(CURRENT_MATCH, jsonString);
editor.apply();
// place this match at the top of the list
Collections.swap(mMatches, 0, position);
notifyItemMoved(position, 0);
Intent intent = new Intent(holder.itemView.getContext(), EditMatchActivity.class);
holder.itemView.getContext().startActivity(intent);
break;
case R.id.delete_match:
mMatches.remove(match);
notifyItemRemoved(position);
// delete file from internal storage
File dir = holder.itemView.getContext().getFilesDir();
File file = new File(dir, "match." + match.getMatchId() + ".json");
boolean deleted = file.delete();
Log.d("TAG", "The file was deleted");
break;
}
return false;
}
});
} else {
// If the current item is selected and you click on the side menu -> don't show delete
// delete isn't an option for active Matches
popup.getMenuInflater().inflate(R.menu.popup_menu_no_delete, popup.getMenu());
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
switch (item.getItemId()) {
case R.id.edit_match:
Intent intent = new Intent(holder.itemView.getContext(), EditMatchActivity.class);
holder.itemView.getContext().startActivity(intent);
break;
}
return false;
}
});
}
//displaying the popup menus
popup.show();
}
});
holder.container.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
holder.matchIsActive = true; // maybe this is redundant
String jsonString = MatchHelper.jsonStringFromMatch(holder.imageView.getContext(), match);
GlobalMatch.changeMatch(match);
SharedPreferences.Editor editor = holder.itemView.getContext().getSharedPreferences(
MY_GLOBAL_PREFS, holder.itemView.getContext().MODE_PRIVATE).edit();
editor.putString(CURRENT_MATCH, jsonString);
editor.apply();
Intent intent = new Intent(holder.itemView.getContext(), MainActivity.class);
holder.itemView.getContext().startActivity(intent);
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public int getItemCount() {
return mMatches.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView tvName;
public TextView tvDate;
public ImageView imageView;
public TextView hiddenMatchId;
public View container;
boolean matchIsActive = false;
public ViewHolder(final View itemView) {
super(itemView);
tvName = (TextView) itemView.findViewById(R.id.match_name);
tvDate = (TextView) itemView.findViewById(R.id.match_date);
imageView = (ImageView) itemView.findViewById(R.id.imageView);
hiddenMatchId = (TextView) itemView.findViewById(R.id.match_id_hidden);
container = (View) itemView.findViewById(R.id.list_item_container);
}
}
}
答案 0 :(得分：0)
如果它不起作用，请在交换数据后尝试使用notifyDataSetChanged()作为最后的手段。
答案 1 :(得分：0)
我不确定导致RecyclerView未更新其项目的代码有什么问题。但是从你的代码如下所示
Collections.swap(mMatches, 0, position);
notifyItemMoved(position, 0);
我发现，通过交换集合中的两个项目，您应该移动两个项目，而不仅仅是一个项目。 也就是说，例如，原始列表是[0,1,2,3,4]，交换（列表，0,3）将获得[3,1,2,0,4]。因此，您需要：
notifyItemMoved(position, 0);
notifyItemMoved(1, position);
答案 2 :(得分：0)
我用这个代替了代码，它起作用了：
Collections.swap(mMatches,holder.getAdapterPosition() ,0 );
mRecyclerView.getAdapter().notifyItemMoved(holder.getAdapterPosition(), 0);