回收器视图不更新notifyDataSetChanged上的内容

Question

我正在使用Recycler视图显示元素列表。当我们单击每一行时，每一行上都有一个按钮，状态改变，背景颜色改变。状态更新后，我将调用notifyDataSetChanged（），但recyclerView不会刷新。

else if (allGoals.getStatus() == WorkoutCashConstants.GOALS_ACHIEVE) {
                        boolean networkStatus = checkNetworkStatus();
                        if (networkStatus) {
                            dateFormat = new SimpleDateFormat("yyyy-MM-dd");
                            if (DATE_ACCESS == null) {
                                currentTimeStamp = dateFormat.format(new Date());
                            } else {
                                currentTimeStamp = DATE_ACCESS;
                            }
                            progDialog = ProgressDialog.show(CompanyGoals_AllGoals_Fragment.this.getActivity(), "", "Goal Progress Recorded");
                            progDialog.setCancelable(true);
                            AchieveGoals achieveGoals = new AchieveGoals(Integer.parseInt(allGoals.getGoalID()), currentTimeStamp);
                            Call<AchieveGoals> achieveGoalsCall = apiModule.achieveGoal(achieveGoals);
                            achieveGoalsCall.enqueue(new Callback<AchieveGoals>() {
                                @Override
                                public void onResponse(Response<AchieveGoals> response, Retrofit retrofit) {
                                    progDialog.dismiss();
                                    if (response.isSuccess()) {
                                        progDialog.dismiss();
                                        goalsAchieved = response.body();
                                        if (goalsAchieved.getAppStatusCode() == WorkoutCashConstants.SUCCESS_API) {
                                            realm = Realm.getInstance(getContext());
                                            realm.beginTransaction();
                                            AllGoalsDB goalsDB = realm.where(AllGoalsDB.class)
                                                    .equalTo("goalID", allGoals.getGoalID()).findFirst();

                                            CompeletedDatesDB compeletedDatesDB = realm.createObject(CompeletedDatesDB.class);
                                            compeletedDatesDB.setCompletedDate(currentTimeStamp);
                                            goalsDB.getCompeletedDatesDBs().add(compeletedDatesDB);
                                            realm.commitTransaction();


                                            UserInfoDB userInfoDB = realm.where(UserInfoDB.class)
                                                    .equalTo(WorkoutCashConstants.
                                                            COLUMN_USER_ID, userId)
                                                    .findFirst();

                                            if (userInfoDB != null) {
                                                realm.beginTransaction();
                                                userInfoDB.setSweatPoints(goalsAchieved.getData().getSweatPoints());
                                                realm.commitTransaction();
                                            }




                                            realm.close();



                                            notifyDataSetChanged();

                                        }
                                    }

Answer 1

NotefyDataSetChanged（）检查getItemCount（），如果与适配器关联的列表中的项计数更改，则NotefyDataSetChanged（）生效。在您的情况下，您可以在适配器中使用toggleSelect函数。我附加了我的一个示例适配器，这样，你就可以知道我们如何实现这种行为。

public class ToggleSelectionListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

        private Cursor mCursor;
        private SparseBooleanArray selectedItems;

        public ToggleSelectionListAdapter(Cursor cursor) {
            mCursor = cursor;
            selectedItems = new SparseBooleanArray();
        }

        public void toggleSelection(int pos) {
            if (selectedItems.get(pos, false)) {
                selectedItems.delete(pos);
            } else {
                selectedItems.put(pos, true);
            }
            notifyItemChanged(pos);
        }

        public int getSelectedItemCount() {
            return selectedItems.size();
        }

        public void clearSelections() {
            selectedItems.clear();
            notifyDataSetChanged();
        }

        public class ViewHolder extends RecyclerView.ViewHolder {

            public ViewHolder(final View itemView) {
                super(itemView);

                // Initialize your items of each row here
            }

            public void bindView(int pos) {
                try {
                    if (mCursor.isClosed())
                        return;

                    mCursor.moveToPosition(pos);

                    // Maintain a checked item list so that you can have a track if the item is clicked or not
                    if (checkedItems.contains(number) itemView.setBackgroundResource(R.drawable.background_selected);
                    else itemView.setBackgroundResource(R.drawable.background_normal);

                    itemView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                                    if (checkedItems.contains(number)) {
                                        checkedItems.remove(number);
                                    } else {
                                        checkedItems.add(number);
                                    }

                                // Get the index of which item should toggle the background
                                int idx = mRecyclerView.getChildAdapterPosition(v);
                                toggleSelection(idx);
                            }
                        }
                    });
            }
        }


        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

            View v;

            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_row, parent, false);

            ViewHolder vh = new ViewHolder(v);

            return vh;
        }

        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

            if (holder instanceof ViewHolder) {
                ViewHolder vh = (ViewHolder) holder;

                vh.bindView(position);

            }
        }

        @Override
        public int getItemCount() {

            if (mCursor == null) {
                return 0;
            }

            int n = mCursor.getCount();
            return n;
        }

        @Override
        public int getItemViewType(int position) {
            return super.getItemViewType(position);
        }

        synchronized public void swapCursor(Cursor cursor) {
            mCursor = cursor;
            notifyDataSetChanged();
        }
    }