Android custom dialog problem

LayoutInflater inflater = getActivity().getLayoutInflater();
                View dialog_view = inflater.inflate(R.layout.progressdialog, null);
                AlertDialog.Builder dialog = new AlertDialog.Builder(getActivity());
                dialog.setView(dialog_view);
                TableLayout table_layout = (TableLayout)dialog_view.findViewById(R.id.Table_view_in_dialog);
                for (int i = 1; i <= 4; i++) {

                    TableRow row = new TableRow(getActivity());
                    row.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
                            LayoutParams.WRAP_CONTENT));

                    // inner for loop
                    for (int j = 1; j <= 4; j++) {

                        TextView tv = new TextView(getActivity());
                        tv.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
                                LayoutParams.WRAP_CONTENT));
                        tv.setBackgroundResource(R.drawable.cell_shape);
                        tv.setPadding(5, 5, 5, 5);
                        tv.setText("R " + i + ", C" + j);
                        row.addView(tv);

                    }

                    table_layout.addView(row);

                }
                AlertDialog alert = dialog.create();
                alert.show();