0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin() Topic is solved

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EiderOsei
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0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by EiderOsei » Tue Aug 24, 2021 8:38 am

Hi, I have installed Joomla 4 and updated to version 4.1. Then I have installed a template to test. I'm not sure about the compatibility of the template. In any case it has disabled Joomla 4. The system has crashed and I only see the following error:

0 Call to undefined method Joomla \ CMS \ Application \ AdministratorApplication :: isAdmin ()

Can anyone help me?

Thanks !!!

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pe7er
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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by pe7er » Tue Aug 24, 2021 8:48 am

Welcome to Joomla forum!

You probably mean Joomla 4.0.1 as version 4.1 has not been developed yet.

There is an issue with Joomla 4.0.1: https://docs.joomla.org/J3.x:Upgrades_t ... or_message
Joomla 4.0.2 will be released later today.
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sozzled
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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by sozzled » Tue Aug 24, 2021 9:01 am

EiderOsei wrote:
Tue Aug 24, 2021 8:38 am
0 Call to undefined method Joomla \ CMS \ Application \ AdministratorApplication :: isAdmin ()
See https://docs.joomla.org/Potential_backw ... n_Joomla_4, search for isAdmin() and then fix the code in the file that caused the error in the first place. When you talk about compatibility in templates, my advice is simple: every template developed before 2017 will definitely not work with J! 4; 95% of templates developed between 2017 and 2021 will probably not work; there are a few third-party templates that may work but I haven't looked for any, yet.
“If you think I’m wrong then say, ‘I think you’re wrong.’ If you say ‘You’re wrong!’, how do you know?” :)

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by brian » Tue Aug 24, 2021 11:31 am

every template developed before 2017 will definitely not work with J! 4; 95% of templates developed between 2017 and 2021 will probably not work; there are a few third-party templates that may work but I haven't looked for any, yet.
FUD based on guesswork
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sozzled
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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by sozzled » Tue Aug 24, 2021 1:27 pm

“If you think I’m wrong then say, ‘I think you’re wrong.’ If you say ‘You’re wrong!’, how do you know?” :)

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by DaffyDuckers » Wed Sep 08, 2021 8:21 pm

Please help, I just installed a new template through extensions - install in 4.0.2 and I'm now getting this error for everything:

0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

How do I undo?

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by sozzled » Wed Sep 08, 2021 8:36 pm

What is the name of this new template—that still uses outdated calls to isAdmin() (deprecated in J! 3 and fatal in J! 4)—that you installed, please?

See also viewtopic.php?f=812&t=988201
“If you think I’m wrong then say, ‘I think you’re wrong.’ If you say ‘You’re wrong!’, how do you know?” :)

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by DaffyDuckers » Wed Sep 08, 2021 9:14 pm


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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by sozzled » Wed Sep 08, 2021 9:21 pm

It appears that template was developed a year-and-a-half ago and there is no statement on the developer's website about that particular template's compatibility with J! 4. If you paid money for the template then you should contact the developer. If you did not pay money for that template then you either have to fix the problem(s) yourself or uninstall it (if that's possible). Sorry, but I don't have any better advice for you.

I don't know anything about that template and I have never used templates from that development company.

Most J! 3 templates won't work with J! 4.
“If you think I’m wrong then say, ‘I think you’re wrong.’ If you say ‘You’re wrong!’, how do you know?” :)

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by timsawers » Thu Sep 16, 2021 3:42 pm

So, having made the mistake of installing an incompatible template into Joomla v4.0.2, I now cannot do anything - how do I uninstall the offending template if I have no access to the back-end to do so! Seriously frustrating! Any help greatly appreciated!

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by iceferret » Mon Sep 27, 2021 2:53 pm

A bit late but i was playing with a localhost version of one of my sites running J4.0.3 and did the same, installed a template that broke the site. RSvario as it happens, resolved by deleting the template files and then searching for all references to the template in PhpMyAdmin and deleting them.
Site now functions again

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by rayainsw » Tue Nov 23, 2021 10:30 pm

How do I do this if I am not able to access any of the backend dashboard?

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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by brian » Tue Nov 23, 2021 11:22 pm

I made a video that will show you how https://youtu.be/ZO9nmdsLlFw
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Re: 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Post by sozzled » Wed Nov 24, 2021 1:28 am

Good video tutorial, Brian. 8)
“If you think I’m wrong then say, ‘I think you’re wrong.’ If you say ‘You’re wrong!’, how do you know?” :)


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