按日历处理后退按钮

Question

我为此苦苦挣扎了几天；如果用户在弹出日历时单击后退按钮。如果用户点击后退按钮，则该字段始终填充当前日期。该类是 een 适配器，没有片段或活动。

什么是正确的解决方案？

这里是代码。

                holder.valueLabel.setOnClickListener(view -> {
                    if (item.value.equals(""))
                        try {
                            String date = new SimpleDateFormat("dd-MM-yyyy").format(new Date());
                            holder.valueLabel.setText(date);

                            DatePickerDialog datePickerDialog = showDatePickerDialog(holder.valueLabel.getText().toString(), new DatePickerDialog.OnDateSetListener() {

                                @Override
                                public void onDateSet(DatePicker view, int year, int month, int day) {
                                    String dateInFormat = getDateInFormat(year, month, day);
                                    holder.valueLabel.setText(dateInFormat);
                                    mItems.get(position).value = dateInFormat;
                                }
                            });
                            datePickerDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Annuleren", (DialogInterface.OnClickListener) (dialog, which) -> {

                                if (which == DialogInterface.BUTTON_NEGATIVE) {
                                    String dateCancel = "";
                                    holder.valueLabel.setText("");
                                    mItems.get(position).value = dateCancel;

                                } else {
                                }
                            });
                            datePickerDialog.show();
                        } catch (ParseException e) {
                            e.printStackTrace();
                        }
                    else {
                        try {

                            DatePickerDialog datePickerDialog = showDatePickerDialog(holder.valueLabel.getText().toString(), new DatePickerDialog.OnDateSetListener() {
                                @Override
                                public void onDateSet(DatePicker view, int year, int month, int day) {
                                    String dateInFormat = getDateInFormat(year, month, day);
                                    holder.valueLabel.setText(dateInFormat);
                                    mItems.get(position).value = dateInFormat;
                                }

                            });
                            datePickerDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Veld leegmaken", (DialogInterface.OnClickListener) (dialog, which) -> {
                                if (which == DialogInterface.BUTTON_NEGATIVE) {
                                    String dateCancel = "";
                                    holder.valueLabel.setText("");
                                    mItems.get(position).value = dateCancel;
                                } else {

                                }
                            });
                            datePickerDialog.show();
                        } catch (ParseException e) {
                            e.printStackTrace();
                        }
                    }
                });

Answer 1

如果您想在按下时关闭对话框，请执行以下操作：

• 全局声明 DatePickerDialog

• 现在 onBackPressed()，检查对话框是否显示为：

  @Override
  public void onBackPressed() {
     if(dialog != null || dialog.isVisible()){
        dialog.dismiss();
        dialog = null;
     }
  }