android - ExpandableListView- 更新或删除特定行而不调用 Activity 中的适配器

Question

从数据库中获取数据后，我实现了一个 expandableListview。数据在列表中正常显示，子项详细信息页面上的 onClicking() 正在打开，用户可以在其中删除数据并编辑数据。但是在返回到 MainActivity 之后，我必须再次调用 OnResume 中的 Adpater 类来重新加载我不需要的数据。我只想删除 或显示更新的 数据。我已经尝试使用 notifyDataSetChanged() 但它没有用，可能是我在错误的地方使用了它。请稍微指导一下...

适配器类..

public class TransExpAdapter extends BaseExpandableListAdapter {
    private Context context;
    List<ExcelDataModel> list_shareofshelf;

    public TransExpAdapter(Context context, List<ExcelDataModel> list_shareofshelf) {
        this.context = context;
        this.list_shareofshelf = list_shareofshelf;
    }


    @Override
    public Object getChild(int listPosition, int expandedListPosition) {
        return this.list_shareofshelf.get(listPosition);
    }

    @Override
    public long getChildId(int listPosition, int expandedListPosition) {
        return expandedListPosition;
    }

    @Override
    public View getChildView(final int listPosition, final int expandedListPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View cview = layoutInflater.inflate(R.layout.list_child_sos, null);

        RelativeLayout child_container = cview.findViewById(R.id.child_container);
        TextView tv_category = cview.findViewById(R.id.tv_category);
        TextView tv_expense = cview.findViewById(R.id.tv_expense);
        ImageView iv_icon = cview.findViewById(R.id.iv_icon);

        try {
            if (list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getIcon_name() != null &&
                    !list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getIcon_name().isEmpty()) {
                int imageid = context.getResources().getIdentifier(list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getIcon_name(), "drawable", context.getPackageName());
                iv_icon.setImageResource(imageid);
            } else {
                iv_icon.setImageResource(R.drawable.ic_gray_no_img);
            }
        } catch (Exception e) {
            iv_icon.setImageResource(R.drawable.ic_gray_no_img);
        }

        if (list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getIncome_Expenses().equalsIgnoreCase("Expenses")) {
            tv_expense.setText("-" + list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getAmount());
        } else {
            tv_expense.setText(list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getAmount());

        }


        child_container.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if (!list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getId().isEmpty()) {
                    Intent i = new Intent(context, ExpenseDetails.class);
                    i.putExtra("trans_id", list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getId());
                    context.startActivity(i);
                }
            }
        });

        if (!list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getMemo().isEmpty()) {
            tv_category.setText(list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getMemo());
        } else {
            tv_category.setText(list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getCategory());
        }

        if (expandedListPosition == list_shareofshelf.get(listPosition).getGroupFocAll().size() - 1) {
            child_container.setBackgroundResource(R.drawable.card_bottom_round);
        }

        return cview;
    }


    @Override
    public int getChildrenCount(int listPosition) {
        return list_shareofshelf.get(listPosition).getGroupFocAll().size();
    }

    @Override
    public Object getGroup(int listPosition) {
        return list_shareofshelf.get(listPosition).getGroupFocAll();
    }

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

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

    @Override
    public View getGroupView(int listPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = layoutInflater.inflate(R.layout.list_parent_sos, null);
        ExpandableListView eLV = (ExpandableListView) parent;
        eLV.expandGroup(listPosition);
        TextView listTitleTextView = view.findViewById(R.id.listTitle);

        TextView tv_expenditures = view.findViewById(R.id.tv_expenditures);
        listTitleTextView.setText(Utils.getFormattedDate(list_shareofshelf.get(listPosition).getDate()));

        tv_expenditures.setText("Expenses: " + list_shareofshelf.get(listPosition).getExp_amt_() + " Income: " + list_shareofshelf.get(listPosition).getInc_amt_());


        return view;
    }

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

    @Override
    public boolean isChildSelectable(int listPosition, int expandedListPosition) {
        return true;
    }

    @Override
    public void registerDataSetObserver(DataSetObserver observer) {
        super.registerDataSetObserver(observer);
    }
}

MainActivity 调用...

private class AsyncTaskGetTransactionData extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... voids) {
            list_final_transaction_data = db.getTransactionDetails(current_month);
            return null;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            if (list_final_transaction_data.size() > 0) {
                expandableListAdapter = new TransExpAdapter(context, list_final_transaction_data);
                expandableListView.setAdapter(expandableListAdapter);
                expandableListView.setVisibility(View.VISIBLE);
                new AsyncTaskSummationExpenses().execute();
            } else {
                tv_income.setText("0");
                tv_expenses.setText("0");
                tv_balance.setText("0");
                p.dismiss();
                expandableListView.setVisibility(View.GONE);
            }
        }
    }

////数据库方法

 public List<ExcelDataModel> getTransactionDetails(String current_month) {
        List<ExcelDataModel> listProd = new ArrayList<>();
        Log.d("CurrentMonthDB", current_month);

        SQLiteDatabase db = this.getWritableDatabase();
        try {
            String selectQuery = "select f.date,(select sum(amount) from tbl_transactions WHERE trans_type='Expenses' and date=f.date)exp, " +
                    "(select sum(amount) from tbl_transactions where trans_type='Income' and date=f.date)inc from tbl_transactions f where f.date like '%" + current_month + "%' GROUP by f.date ORDER BY strftime('%s', f.date) desc";

            Log.d("FirstQuery", selectQuery);
            Cursor c = db.rawQuery(selectQuery, null);
            if (c.moveToFirst()) {
                do {
                    ExcelDataModel foc_cat = new ExcelDataModel();
                    String date = c.getString(c.getColumnIndex("date"));
                    String income = c.getString(c.getColumnIndex("inc"));
                    String expense = c.getString(c.getColumnIndex("exp"));
                    String selectQuery1 = "select * from tbl_transactions a LEFT join tbl_category b where a.cat_id=b.cat_id and date='" + date + "' order by memo asc";
                    Log.d("SecondQuery", selectQuery1);
                    Cursor cursor2 = db.rawQuery(selectQuery1, null);
                    if (cursor2.moveToFirst()) {
                        List<ExcelDataModel> subCat_list = new ArrayList<>();
                        // ExcelDataModel pp_dummy = new ExcelDataModel();
                        //pp_dummy.setId("");
                        // subCat_list.add(pp_dummy);
                        do {
                            ExcelDataModel prod_subcat = new ExcelDataModel();
                            prod_subcat.setDate(cursor2.getString(cursor2.getColumnIndex("date")));
                            prod_subcat.setIncome_Expenses(cursor2.getString(cursor2.getColumnIndex("trans_type")));
                            prod_subcat.setCategory(cursor2.getString(cursor2.getColumnIndex("cat_name")));
                            prod_subcat.setMemo(cursor2.getString(cursor2.getColumnIndex("memo")));
                            prod_subcat.setAmount(cursor2.getString(cursor2.getColumnIndex("amount")));
                            prod_subcat.setId(cursor2.getString(cursor2.getColumnIndex("trans_id")));
                            prod_subcat.setIcon_name(cursor2.getString(cursor2.getColumnIndex("cat_iconname")));
                            subCat_list.add(prod_subcat);
                        } while (cursor2.moveToNext());
                        foc_cat.setDate(date);

                        if (expense != null) {
                            foc_cat.setExp_amt_(Double.parseDouble(expense));
                        } else {
                            foc_cat.setExp_amt_(0);
                        }

                        if (income != null) {
                            foc_cat.setInc_amt_(Double.parseDouble(income));
                        } else {
                            foc_cat.setInc_amt_(0);
                        }

                        foc_cat.setDate(date);
                        foc_cat.setGroupFocAll(subCat_list);
                        listProd.add(foc_cat);
                        cursor2.close();
                    }
                } while (c.moveToNext());
            }
            c.close();
            db.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db != null)
                db.close();
        }
        return listProd;
    }

Answer 1

尝试在子项的 OnClick() 上使用回调并在 Activity 中捕获该回调，这样您就可以执行 startActivityForResult() 而不仅仅是 startActivity().

这样您就可以知道用户何时删除了详细信息 Activity 中的某些内容，即在该 Activity 被销毁之后。然后，在 onActivityResult 中执行 yourAdapter.notifyDataSetChanged();

像这样，在适配器中:

child_container.setOnClickListener(new View.OnClickListener() {

    @Override
         public void onClick(View v) {
         if (!list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getId().isEmpty()) {
              callback.childClicked(list_shareofshelf.get(listPosition).getGroupFocAll().get(expandedListPosition).getId());
         }
     }
});

然后，在您的 Activity 中，您实现回调

@Override
public void childClicked(int id){
    Intent i = new Intent(context, ExpenseDetails.class);
    i.putExtra("trans_id", id);
    startActivityForResult(i, yourRequestCode);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable 
    Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == yourRequestCode) {
        if (resultCode == RESULT_DELETED) {
            adapter.notifyDataSetChanged();
        }
    }
}