Add ndbCurrentView method & ndbViewChanged signal

[shermp]

This PR adds a method to find out what the currently shown view is (eg: HomePageView, ReadingView). It also adds a signal that is emitted every time the current view changes.

I search the result of QApplication::allWidgets() for a QStackedWidget which contains the HomePageView widget. I only search once, then cache the QStackedWidget pointer for subsequent calls. This method works as far back as firmware version 4.6.x.

According to @pgaskin this QStackedWidget is managed by the MainWindowController singleton. I can't figure out a way of getting it from the MWC, especially on older firmware versions. Unless anyone has any further ideas, I'll stick with the QApplication method.

[shermp]

Works well, but it would be useful to see if the N3Dialogs can be named more specifically.

That would be nice. I'll see if Kobo have set windowTitle.

EDIT: Nope, at least not in 4.6. It has been set for the home page, and "My Books", but not for the dialogs 😞

[shermp]

I finally figured out how to get the title of an N3Settings dialog. Tried N3Settings::getTitle() and N3Settings::getTitleLarge(), but couldn't figure out the proper return type. Tried char*, QString, QString*, QByteArray. Nothing seemed to work.

Digged further into the code, and found they returned a SmallLabel* and HeaderMediumLabel* respectively, both of which seem to be derived from QLabel.

And sure enough, calling QLabel::text() for the N3Settings::getTitleLarge() return value gives a useful title 😁

@pgaskin I've tested on FW 4.6, could you try a newer version please?

[shermp]

Found a much better way of getting the current dialog name, that isn't tied to the current language. Turns out N3Dialog is more of a generic wrapper than anything else. It contains a widget that has the dialog contents.

This widget can be obtained by calling N3Dialog::content(), and one can get the the object name from the returned QWidget pointer.

[root@(none) ~]# qndb -m ndbCurrentView
N3SettingsView
[root@(none) ~]# qndb -m ndbCurrentView
N3SettingsDeviceInformationView

[shermp]

Well, the NH failsafe just saved me from having to factory reset... Hooray for the failsafe 😀

For those wondering, apparently QTimer really prefers to be heap allocated.

[shermp]

Could you have one last quick look please @pgaskin when/if you get a moment?

I've now added a crude debounce style filter to prevent duplicate signals being sent, like what was happening before in FW 4.6

Otherwise I think I'm done, barring any issues.

[shermp]

Looks good. Tested on FW 15548.

Thank you very much.

I know you're currently pretty busy, so thanks for taking the time to look at this. It's most appreciated.