Performance issues

[Kyle Cureau]

Congrats on Kendo UI Mobile performance.  It's certainly the fastest framework around.

However there is one place where I can notice a significant performance lag: checkboxes and radios.  On the mobile emulator it performs fine, after wrapping a Kendo App in PhoneGap/Cordova, there is a half-second delay between selecting a checkbox and the appearance of the check.

Is this a known issue?  If so, is there anything I can do to fix it?

Does FastClick help in this case.  I'm under the impression that FastClick won't help a Kendo app wrapped in PhoneGap because Kendo already uses the touch event for all browsers.  Is this impression correct?

[Kiril Nikolov]

Hi Emile,

I really happy to hear that you like our product.

I am afraid that this performance issue that you are describing is not a known one. What devices do you use for testing? Could you please extract a sample of your test project that we can take a look at, as I was not able to reproduce it?

As for the FastClick- you are correct that Kendo UI Mobile already implements the touch events in all browsers, so you do not really need a 3rd party solution for that. You can check the following article, explaining it a bit more:

http://docs.kendoui.com/getting-started/mobile/touch

Regards,
Kiril Nikolov
Telerik

[Cynthia]

We're pleased with the overall performance of Kendo as well. However, we are also noticing this issue on devices (iPhone 5s running iOS 7 to name one). It happens even with the Kendo demo found here:

http://demos.kendoui.com/mobile/forms/checkboxes.html

There is a noticeable delay between tapping the checkbox/radio element and the change event firing. We were able to fix this with a radio list as follows:

1. Add a data-click handler to the ul element containing the radio buttons. Assume that the radio button inputs are bound to a variable (ex, data-bind="myRadioButtonValue") in a view model (kendo.observable).

2. The data-click handler for the ul element looks something like this:

clickRadioList: function(e) {
  var obj = $(e.target).closest('li');
  if (obj) {
      var input = obj.find('input');
      myViewModel.set("myRadioButtonValue", input.attr('value'));
  }
}

As a result of the data binding, the radio button will change to its new state immediately. However, implementing this work around for each set of radio buttons isn't ideal.

Would Kendo be able to look into optimizing checkbox and radio elements? As a potentially related issue, we're also noticing poor performance on some devices (ex, iPhone 4) in cases where we have about 80 radio buttons in a filterable list.

[Max]

Kiril, this seems not to be correct anymore as of Q2-2013. Please see http://www.kendoui.com/forums/kendo-ui-mobile/general-discussions/checkbox-delay-on-tap.aspx

Could you please look into this and, if this is really the case, let me know on how to integrate a fastclick solution for checkbox (and radio button?) elements so it doesn't conflict with the rest of kendo ui mobile? (Simply attaching fastclick to the body seems to interfere with some things, e.g. the links in the drawer)

PS: And/Or, of course, actually fix the underlying issue so that there is no tap delay on checkboxes

[Kiril Nikolov]

Hi Guys,

We have been experimenting with a fast click like implementation and many other ways in order to improve the performance, however all of the methods turned out to be unreliable and we had to settle with the current implementation. 

As for the FastClick implementation - as it is a third party solution we cannot assist you in implementing that, and furthermore we will not be able to support  you if any issue occur due to its implementation.

Regards,
Kiril Nikolov
Telerik

[Murtie]

Are there any updates on this? I am having the same issue... my click events only register if I do them slowly :-(

Thanks,
Murtie

[Kiril Nikolov]

Hello Murtie,

I am afraid that there are no updates on the way checkboxes and radio buttons are implemented in Kendo UI Mobile. We still have not found a better way to approach this functionality that will work equally well on all platforms.

Regards,
Kiril Nikolov
Telerik