connect won't...

[Anonymous_Banned275]

This post is deleted!

[Axel Spoerl]

@AnneRanch
Add

qDebug() << __FUNCTION__ << __LINE__ << index_sub << subAction[index_sub];

…after the call to setCheckable() and before the connect and post the output. That’s how to debug this.

[Anonymous_Banned275]

This post is deleted!

[sierdzio]

@Axel-Spoerl said in connect won't...:

FUNCTION << LINE

Can be shortened to Q_FUNC_INFO.

[Axel Spoerl]

@AnneRanch said in connect won't...:

Here's your problem:

QObject::connect(QAction, MainWindow_Bluetooth): invalid nullptr parameter

The array you use for the connect statement isn't populated properly.
At this location:

connect(subAction[index_sub] , &QAction::triggered, this ,
                               [=]() { this->process_TEST() ;});

...you have a nullptr in subAction[index_sub].

That's probably a result of the somewhat unusual approach to store actions in an array.