Cannot read property 'scrollView' of undefined

Question

I got this error when using uniGUI framework for executing JS code.

Cannot read property 'scrollView' of undefined

This property is used in this procedure.

procedure SetScrollboxSize(AFramem: TWPUnimFrame; ASize: Integer);
begin
  if ASize > AFramem.ScrollBoxm.ClientHeight then
    UniSession.JSCode(AFramem.Scrollboxm.JSName
                      + '.scrollableBehavior.scrollView.getScroller().maxPosition.y = '
                      + (ASize - AFramem.Scrollboxm.ClientHeight).ToString + ';')
  else
    UniSession.JSCode(AFramem.Scrollboxm.JSName
                      + '.scrollableBehavior.scrollView.getScroller().maxPosition.y = 0;');
end;

Can you give me a hint where to search or where to start to fix this bug?

I see that the question is updated and probably this component set is based on Sencha Touch 2.3.1. Again, try to change your JavaScript code or read the docs about [Ext.Container.getScrollable](https://docs.sencha.com/touch/2.3.1/#!/api/Ext.Container-method-getScrollable). — Zhorov, Feb 27 '19 at 13:50

Zhorov · Answer 1 · 2019-02-26T14:15:02.323

It's difficult to reproduce your error without the actual source code, but "Cannot read property '...' of undefined" is typical JavaScript error. I guess that TWPUnimFrame is some kind of component for displaying web content.

In your case you need to make sure that AFramem.Scrollboxm.JSName + '.scrollableBehavior' variable is assigned. You may try to output some information with console.log() and debug JavaScript code:

procedure SetScrollboxSize(AFramem: TWPUnimFrame; ASize: Integer);
var
    code: string;
begin
    code := 'console.log(' + AFramem.Scrollboxm.JSName + 'scrollableBehavior.scrollView); ';
    if ASize > AFramem.ScrollBoxm.ClientHeight then
        code := code +
            AFramem.Scrollboxm.JSName + 
            '.scrollableBehavior.scrollView.getScroller().maxPosition.y = ' +
            (ASize - AFramem.Scrollboxm.ClientHeight).ToString + ';'
    else
        code := code +
            AFramem.Scrollboxm.JSName +
            '.scrollableBehavior.scrollView.getScroller().maxPosition.y = 0;';
    UniSession.JSCode(code);
end;

@KenWhite Yes, but if I understand the question correctly, OP tries to execute JavaScript code. Thanks for this note, I didn't notice that `JavaScript` tag is missing. — Zhorov, Feb 26 '19 at 18:32

Cannot read property 'scrollView' of undefined

1 Answers1