Qt subwidget automatic resizing in QHBoxLayout - qt

I have a QTableView. When the table grows, the table view adds scrollbars, even when it could just expand to take more room in the QHBoxLayout. How do I make it expand?

Related

Splitter between items in a QTreeView

I want to resize an items height in a QTreeView separately for each item.
Is there an easy way to make splitters between each items in a QTreeView?

Qt-designer: enlarging the window does not replace my items

To keep the question as simple as possible, I prepared a simple Qt designer form below
There is a Tab Widget on the left side and empty QWidget on the right side, the QWidget as a GroupBox. The Groupbox has a radio and pusbuttons (you can see them on Object inspector window on the photo as well ). The tab widget has a line edit. The central widget has a gridlayout and horizontal qsplitter is used.
My issue is that when I enlarge the window, all items (lineedit, radiobutton, pushbutton) are on the fix position. Here is an example what I mean:
What I want is that when the window is enlarged the items should be placed on the bottom of the window, or if they are in the middle, then they should stay in the middle. ( I don't want size of the buttons/lineedits to be changed).
How can I do it?
The items you want to move dynamically, with window resizing must be in a layout.
So, in the example you've posted, you need two layouts; one inside the tab widget, for the QLineEdit and at least one in the GroupBox for the radio button and push button.
If you want the radio and push button to be aligned horizontally, you can start by placing them in a horizontal layout, before placing that layout in another, which all reside in the group box.
When you start to add items to layouts, such as push buttons, you'll start to notice that they can get stretched, so you may need to set the size policies of the widgets.
If you want the line edit to be centered horizontally, you will have to place two horizontal spacers on each side of the line edit and select the three together and set "Lay out Horizontally". This can found at the top toolbar in Qt Designer.
To always have it at the bottom of the tab widget, put a vertical spacer above the line edit in your tab widget. Then select the option "Lay out vertically" for the tab widget.
The same goes for your radio button and push button. Keep them in a horizontal layout, with horizontal spacers if required and put a vertical spacer into the group box and set the layout property for the group box as "Lay out Vertically".
Most important of all, I suggest you go through some basic tutorials before you continue. Here is a link to a good channel on youtube.
https://www.youtube.com/playlist?list=PL2D1942A4688E9D63
If you don't have a layout in your tabWidget or GroupBox:
You must set a layout (for example QVBoxLayout) inside your tab widget and a group box.
It can be done using QtDesigner. It also can be done in code like this:
QWidget *window = new QWidget;
QPushButton *button1 = new QPushButton("One");
QPushButton *button2 = new QPushButton("Two");
QPushButton *button3 = new QPushButton("Three");
QPushButton *button4 = new QPushButton("Four");
QPushButton *button5 = new QPushButton("Five");
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(button1);
layout->addWidget(button2);
layout->addWidget(button3);
layout->addWidget(button4);
layout->addWidget(button5);
window->setLayout(layout);
But if you do, and then you want your buttons to stay at the bottom:
Then you have to try setRowStretch method http://qt-project.org/doc/qt-4.8/qgridlayout.html#setRowStretch or take a look at QSpacerItem.

How to prevent QTableWidget from occupying the whole window in a QHBoxLayout?

In my Qt program, I programmatically generate a modal QDialog. I want to show two widgets in this dialog window: A custom widget showing a camera output and a QTableWidget, showing the pixel coordinates of the corners found in the camera image. I generate a QHBoxLayout and add my custom widget and the QTableWidget into it. Then I set this QHBoxLayout as the Layout of the QDialog window. What I want to achieve is to share the available space in the QDialog's window area equally between my custom QWidget and the QTableWidget, horizontally, by using a QHBoxLayout. But I always end up with QTableWidget occupying the whole QDialog area, by overlapping my custom widget. How can I instruct these two widgets to exactly share the QDialog area?? Note that I first add my custom widget and then the QTableWidget into the QHBoxLayout.
Make sure on your custom widget you've specified a minimumSizeHint and a sizeHint, this instructs the QLayout manager that the widget requires a specific space. To have them split equally you'll be best off detecting the size of the QDialog and then specifying the width for both by removing the boundary sizes (spacing between widgets + space to QDialog edge) and dividing it up.

Qt Layout Flexible Grid

I have a bunch of buttons in Qt with a fixed size. Now I want to create a layout in which they are shown in a grid. I want the grid to be scrollable and when I resize my mainwindow, the grid should fit as much buttons in the layout as possible. The number of rows and columns are therefore not fixed.
I tried creating this with the hbox, vbox and gridlayout but they either put all the buttons below each other, or side by side. Also it resizes my mainwindow to an enormous size to fit all the buttons in.
Any Ideas?
Put QScrollArea inside your QMainWindow. Apply QGridLayout to QScrollArea's inside widget and put the buttons inside it.

Resizing a QDialog after adding components to a child widget

I'm a bit new to QT but have to work on existing code. Here's the case:
I have a class extending QDialog. the constructor sets a QGridLayout then adding three other widgets to it. One of the widgets is a QScrollArea containing a QGroupBox. this QGroupBox has a QVBoxLayout and there I'm adding a list of widgets at runtime. The size of the scroll area should grow until a given limit is reached before showing the scrollbars so that they are only used when the dialog would grow too high. I've found that the sizeHint of the outer layout doesn't update when the sizeHint of the scroll area updates. How can I refresh this, or is there a better way to resize the parent dialog?
What about using widgetResizable property of QScrollArea? It should try to resize view to avoid using scorllbars.

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