Delphi 10.4.2 FMX: How to write the case where the user press return button on android phone instead of choice in message dialog box?

Question

    MessageDlg('Please turn on your gps', TMsgDlgType.mtConfirmation,
    [
      TMsgDlgBtn.mbYes,
      TMsgDlgBtn.mbNo,
      TMsgDlgBtn.mbClose
    ], 0,
    procedure(const AResult: TModalResult)
    begin
      case AResult of
        mrYES: begin
          LIntent := TJIntent.JavaClass.init(TJSettings.JavaClass.ACTION_LOCATION_SOURCE_SETTINGS);
          TAndroidHelper.Context.startActivity(LIntent);
        end;
        mrNo:
          Close;
        mrClose:
          Close;
        mrNone:
          Close;
      end;
    end);

Here are some code snippet I have been trying, I don't want to let the user proceed and close the app when the user click return button on the phone.

It is not really clear what your question is, or what problem you are having. — Remy Lebeau, Dec 14 '21 at 01:37
@RemyLebeau when I use yes or no in the message dialog box, its handled properly, yes will proceed, no will quit. But if I click phone back button instead of yes or no, it proceed and give wrong result. I want to make it quit like no, if back key is clicked on phone. — RenSword, Dec 14 '21 at 02:06
I would use an `if-else` instead of a `case`, eg: `if AResult = mrYes then begin ... end else Close;` If that is not working, then you should [file a bug report](https://quality.embarcadero.com) with Embarcadero, as the phone's Return button should not trigger the callback with `mrYes`, or even skip the callback altogether. I would expect the callback to be called with `mrClose` or `mrCancel` — Remy Lebeau, Dec 14 '21 at 02:08
Test for AResult = -1, which is what is passed if the user uses the Back (which is what I assume you meant instead of Return) button. Using a debugger would have revealed that. I recommend learning how to debug — Dave Nottage, Dec 14 '21 at 02:38
Be aware that messagedlg is deprecated as you can see [here](https://docwiki.embarcadero.com/Libraries/Sydney/en/FMX.Dialogs.MessageDlg#:~:text=Warning%3A%20MessageDlg%20is%20deprecated). You should use Platform.IFMXDialogServiceAsync.MessageDialogAsync — Xalo, Dec 15 '21 at 17:32

score 0 · Accepted Answer · answered Dec 14 '21 at 02:53

Thanks for everyone help. if-else case work.

    MessageDlg('Please turn on your gps', TMsgDlgType.mtConfirmation,
    [
      TMsgDlgBtn.mbYes,
      TMsgDlgBtn.mbNo
    ], 0,
    procedure(const AResult: TModalResult) begin
      if AResult = mrYES then begin
          LIntent := TJIntent.JavaClass.init(TJSettings.JavaClass.ACTION_LOCATION_SOURCE_SETTINGS);
          TAndroidHelper.Context.startActivity(LIntent);
      end
      else Close;
    end);

Delphi 10.4.2 FMX: How to write the case where the user press return button on android phone instead of choice in message dialog box?

1 Answers1