Using custom QWidgets in QListWidgets

[mrjj]

@Hubbard
Oh, sorry, misread the names it seems.
But if u insert exampleUnitAddress->ribbonAddress
are you inserting a widget that lives in other widget ?
When you insert a QButton its not inside other widget.
That seems to be the difference ?

[Hubbard]

The QWidget class 'UnitRibbon' (or UnitRibbon *ribbonAddress) is a member class of BioBloomUnit QObject, with a designed UI

[SGaist]

Hi,

Why are you trying to show an inner widget rather than the full BioBloomUnit widget ?

[Hubbard]

@SGaist
The BioBloomUnit isn't a widget with its own graphics (its a QObject), it stores all of the necessary data for an instance of the unit in my project AS WELL AS its own QWidget unitRibbon which displays some of the data, which I want organised into lists

[SGaist]

Then this looks bad. You should decouple the data from their graphic representation aka MVC.

Since you are already using Qt's related class. You should consider implementing a QAbstractListModel that will wrap your list of BioBloomUnit and use a QListView to show them.

By the way, what is ribbonAddress for a widget ?

[Hubbard]

ribbonAddress is a pointer to a UnitRibbon class and is a member in BioBloomUnit, its a widget with its own UI file, BioBloomUnit is NOT a widget and is a normal QObject class, I was to display all of the UnitRibbons for each unit in a list.

[SGaist]

That I understood, hence my suggestion for a separation of concerns. BioBloomUnit should not care about the GUI that should show the data it represents.

[Hubbard]

Would it be better if the UnitRibbons exist in the mainWindow and instead take BioBloomUnit as an argument (either by constructor or member method) to get their data?

[Hubbard]

so I updated my code to the following

UnitRibbon* exampleRibbonAddress = new UnitRibbon;
QListWidgetItem* exampleItemAddress = new QListWidgetItem(ui->UnitList);
//exampleItemAddress->setSizeHint(exampleRibbonAddress->sizeHint());
ui->UnitList->setItemWidget(exampleItemAddress, exampleRibbonAddress);
ui->UnitList->addItem(exampleItemAddress);

Now it only shows the top half of the widget, when the sizeHint is uncommented it becomes invisible entirely

[mrjj]

@Hubbard
Hi
Setting size hint is good idea.
It will use that for widget size when placed on "row"

[SGaist]

Might be a silly question but are you sure your properly set the layouts on your widgets ? Having to call sizeHint like that is surprising.

[Hubbard]

I have removed the graphical widget from my class and made it a separate class and now it is displaying, I'm surprised it works like that, however I've run into a different yet related issue:-

exampleUnitAddress = new BioBloomUnit(this);        //instance example

setupOtherWindows();
setupPushButtons();

UnitRibbon* exampleRibbonAddress = new UnitRibbon;
QListWidgetItem* exampleItemAddress = new QListWidgetItem(ui->UnitList);
exampleItemAddress->setSizeHint(exampleRibbonAddress->size());
ui->UnitList->setItemWidget(exampleItemAddress, exampleRibbonAddress);
ui->UnitList->addItem(exampleItemAddress);

//UnitRibbonPressSlot() calls BioBloomUnit::UnitWindow->show()

connect(ui->ExampleButton, SIGNAL(released()), exampleUnitAddress, SLOT(unitRibbonPressSlot()));

connect(ui->UnitList, SIGNAL(itemClicked(exampleItemAddress)), exampleUnitAddress, SLOT(unitRibbonPressSlot()) );

ExampleButton (a QPushButton on the ui) successfully opens the unit's window, however pressing on the Ribbon for the example Unit does not.

[mrjj]

Hi
When using the old SLOT and SIGNAl macros, you should always
check the return value of connect.
Also you seem to mix signatures/odd syntax
connect(ui->UnitList, SIGNAL(itemClicked(exampleItemAddress)), exampleUnitAddress, SLOT(unitRibbonPressSlot()) );
What is exampleItemAddress ?
and unitRibbonPressSlot should also accept such paramter
Are you sure that UnitLists signal itemClicked have that signature ?

[Hubbard]

void itemClicked(QListWidgetItem *item)

can you explain your response more please?

It takes in the item instanced above (and shown in the list) and has no return

[Hubbard]

What do you mean by the 'old' signal and slot macros?

[Hubbard]

Ah I see, the signals are only allowed to be passed parameter types, not names, so how do I link the specific item clicked on to it's specific unit's window?

[mrjj]

@Hubbard
Hi
Yes for connect, you only list the type and not the parameter name.

The actual parameter is added by the widget that emit the signal.
( in this case when you click something)

Normally, the SLOT should accept the same paramter(s)

by old i mean
https://wiki.qt.io/New_Signal_Slot_Syntax
Its possible to use other syntax that fails at compile time.
The price is a ugly syntax if there are overloaded signals ( one send index, other send string as example)

[Hubbard]

@mrjj
Could you explain what you meant about the actual parameter is passed by the item that's emits the signal please

How could I use this to open a different window for a different item?

[jsulm]

@Hubbard Please read http://doc.qt.io/qt-5/signalsandslots.html
Parameters are not passed at the time you connect a slot to a signal (how would it be possible?), but at the time the signal is emitted. So, the object emitting the signal passes the parameter.
For example lets say you have a class with void someSignal(int someParameter) signal, then an instance of this class would emit the signal like this:

emit someSignal(10);