showing custom widget inside the mainWindow

Christian Ehrlicher

Already answered here: https://forum.qt.io/topic/132782/syntax-for-vector-of-qpushbuttons-added-to-flowlayout/47

jsulm

@Swati777999 said in showing custom widget inside the mainWindow:

Yes, that's where I am stuck

In what way stuck?
I'm really wondering how often we have to repeat same stuff:

Do not create a new QMainWindow in your ScrollAreaApp
Subclass QMainWindow instead of QWidget

I give up...

JKSH

@Swati777999 said in showing custom widget inside the mainWindow:

In this I get 2 windows, one blank window (probably default window of the widget ) and other one is the Main Window.

You said you got your desired results at https://forum.qt.io/post/695547

Now, your new code doesn't have the desired results. So, tell us: What changes did you make?

Swati777999

@JKSH said in showing custom widget inside the mainWindow:

@Swati777999 said in showing custom widget inside the mainWindow:

In this I get 2 windows, one blank window (probably default window of the widget ) and other one is the Main Window.

You said you got your desired results at https://forum.qt.io/post/695547

Now, your new code doesn't have the desired results. So, tell us: What changes did you make?

Thanks for the patience @JKSH. I appreciate that.

Actually ,the entire widget [window with a heading and array of buttons in a vertical layout with scrolling feature]that you see, is a part of another application which is to be imported as a widget.

Now , I'm trying to do something like this :

scrollareaapp.h

class ScrollAreaApp : public QWidget
{
    Q_OBJECT

public:
    ScrollAreaApp(QWidget *parent = nullptr);
    ~ScrollAreaApp();
};

scrollareaapp.cpp

ScrollAreaApp::ScrollAreaApp(QWidget *parent)
    : QWidget(parent)
{  QMainWindow *main = new QMainWindow();


    QWidget *flowWidget = new QWidget(main);
    FlowLayout *flowLayout = new FlowLayout();
    flowWidget->setLayout(flowLayout);
    flowWidget ->setMinimumSize(1200,1200);
    int n=20;
    QVector <QPushButton *> buttons(n);

    for (int ii=0;ii<n;ii++)
    {
        QPushButton * pb = new QPushButton(); // creating buttons

           pb->setMinimumSize(200,200);
           buttons.push_back(pb); // adding buttons to qvector

           flowLayout->addWidget(pb);

    }

    QScrollArea *scroll =new QScrollArea();

    QWidget *WindowWidget= new QWidget(this);
    WindowWidget->setMinimumSize(1000,1000);

    QVBoxLayout *WindowLayout = new QVBoxLayout(WindowWidget);

    QLabel *WindowHeading = new QLabel("Experimenting with Scrollbar in Flow Layout");

    WindowLayout->addWidget(WindowHeading);
    WindowLayout->setAlignment(WindowHeading,Qt::AlignLeft);
    WindowLayout->addWidget(flowWidget);

    scroll->setWidget(WindowWidget);
    main->setLayout(WindowLayout);
    main->setCentralWidget(scroll);

    main->show();
    main->setWindowTitle("Main Window");
}

So this entire widget is to be imported as a widget which fits into the centralWidget of another application.
I hope I made my point clearly.

Swati777999

@jsulm
Thanks for all help. Please ignore my doubts if you find them silly.

Pl45m4

@Swati777999 said in showing custom widget inside the mainWindow:

So this entire widget is to be imported as a widget which fits into the centralWidget of another application

Why you still create a QMainWindow inside your QWidget? You always add one layer which is not necessary.
i believe the task as such is not complicated but the amount of cascading widgets and layouts makes it harder to read.

If your widget needs to be part of another (already existing) widget or QMainWindow, then you dont need so many widgets and layouts in your widget.
Create a widget, assign a main layout, put other content and maybe other layouts with content in, done.
Not every app needs a QMainWindow. It's recommended for stand-alone apps, because QMainWindow provides some nice features like for example the integrated statusBar, but in the end, QMainWindow is just a regular QWidget.
So it is weird to create a QWidget, then create a parentless QMainWindow inside and then show it.

Edit:
Also, AFAICS your main mainWindow "lives" in your widget's constructor only... It will get destroyed if you close your other widget, no matter if the mainWindow is still visible or not.

Swati777999

@Pl45m4 said in showing custom widget inside the mainWindow:

@Swati777999 said in showing custom widget inside the mainWindow:

So this entire widget is to be imported as a widget which fits into the centralWidget of another application

Why you still create a QMainWindow inside your QWidget? You always add one layer which is not necessary.
i believe the task as such is not complicated but the amount of cascading widgets and layouts makes it harder to read.

If you widgets needs to be part of another (already existing) widget or QMainWindow, then you dont need so many widgets and layouts in your widget.
Create a widget, assign a main layout, put other content and maybe other layouts with content in, done.
Not every app needs a QMainWindow. It's recommended for stand-alone apps, because QMainWindow provides some nice features like for example the integrated statusBar, but in the end, QMainWindow is just a regular QWidget.
So it is weird to create a QWidget, then create a parentless QMainWindow inside and then show it.

Edit:
Also, AFAICS your main mainWindow "lives" in your widget's constructor only... It will get destroyed if you close your other widget, no matter if the mainWindow is still visible or not.

My point is there's another application(let's call it MyApp) which has got a design.
My app has got some pushbuttons on the left side of the mainwindow. On clicking pushbutton A , I should be getting the result of the scrollareaApp in the central widget of MyApp.

What you see below is MyApp and I've written the program above for scrollAreaapp

JKSH

@Swati777999 said in showing custom widget inside the mainWindow:

My point is there's another application(let's call it MyApp) which has got a design.

I believe you have missed @Pl45m4's point. He is asking you to explain: What do you expect this line to do?: QMainWindow *main = new QMainWindow();

So this entire widget is to be imported as a widget which fits into the centralWidget of another application.

Well, your ScrollAreaApp should not be the one that tries to import itself to the other application.

You should put code inside the ScrollAreaApp that determines how it looks, all by itself.
Your other application should contain the code that "fits [the ScrollAreaApp] to the other application".

Swati777999

@JKSH said in showing custom widget inside the mainWindow:
I believe you have missed @Pl45m4's point. He is asking you to explain: What do you expect this line to do?: QMainWindow *main = new QMainWindow();
Actually, I was trying to write some codes after that [like setting a layout or so]so as to I can add WindowWidget to it, something like that.

Well, your ScrollAreaApp should not be the one that tries to import itself to the other application.

You should put code inside the ScrollAreaApp that determines how it looks, all by itself.

2. Your other application should contain the code that "fits [the ScrollAreaApp] to the other application".
Yes, my other application has code for it and I should be writing this code there while trying but I chose to create another project file for experimenting.

JKSH

@Swati777999 said in showing custom widget inside the mainWindow:

@JKSH said in showing custom widget inside the mainWindow:
I believe you have missed @Pl45m4's point. He is asking you to explain: What do you expect this line to do?: QMainWindow *main = new QMainWindow();
Actually, I was trying to write some codes after that [like setting a layout or so]so as to I can add WindowWidget to it, something like that.

You should add your WindowWidget to your ScrollAreaApp (which is this in your ScrollAreaApp's constructor). You should not be adding it to some extra QMainWindow.

Yes, my other application has code for it and I should be writing this code there while trying but I chose to create another project file for experimenting.

Unfortunately, the way that you're carrying out these experiments is making it harder for you to understand the important basics of widget parent-child relationships and layout management.

In summary: It is completely wrong to create a new QMainWindow() in your custom widget's constructor. Don't do it, ever... not even for experimenting. This is because the ScrollAreaApp's constructor should only contain things that are placed inside the ScrollAreaApp. (Does this make sense? If not, please ask)

Swati777999

@JKSH said in showing custom widget inside the mainWindow:

@Swati777999 said in showing custom widget inside the mainWindow:

@JKSH said in showing custom widget inside the mainWindow:
I believe you have missed @Pl45m4's point. He is asking you to explain: What do you expect this line to do?: QMainWindow *main = new QMainWindow();
Actually, I was trying to write some codes after that [like setting a layout or so]so as to I can add WindowWidget to it, something like that.

You should add your WindowWidget to your ScrollAreaApp (which is this in your ScrollAreaApp's constructor). You should not be adding it to some extra QMainWindow.

Yes, my other application has code for it and I should be writing this code there while trying but I chose to create another project file for experimenting.

Unfortunately, the way that you're carrying out these experiments is making it harder for you to understand the important basics of widget parent-child relationships and layout management.

In summary: It is completely wrong to create a new QMainWindow() in your custom widget's constructor. Don't do it, ever... not even for experimenting. This is because the ScrollAreaApp's constructor should only contain things that are placed inside the ScrollAreaApp. (Does this make sense? If not, please ask)

I completely understand what you want to convey. So, basically it is preferred to experiment in the same location of the complete application rather than writing a part of code in different project file.