I have main window and in this window I have QListWidget. I want this list to be central widget in the main window and I know that I can do that by writing code like setCentralWidget(QWidget*) and it works (list is spread on the whole mainwindow) but this isn't reflected in designer when the list is still in this same position and has the same size. Is there any way to make it so the change is visible in designer as well as in the code?
Thank you.
In Designer, right click on an area of the form next to the QListWidget, then choose Layout->Layout Horizontally (or vertically, almost anything is acceptable).
I figured it out. In order to do so I had to choose grid layout for main window and sizePolicy for list as Prefered.
Related
So I currently have got a custom widget, and I want to add them to the main window after clicking a button. I would like to add them all to one fixed position first and then I will be able to drag them wherever I like. I am able to create and display these custom widgets with help of QHBoxLayout or QVBoxLayout, but in this case they will not be in the same position after I create them. Any help will be appreciated!
As the names suggest, the QLayout classes manage the position and geometry of the items added to them. You cannot move (eg. drag) an item out of a layout w/out first removing it from the layout (QLayout::removeItem() and derivatives). For example when you drag a toolbar or dock widget out of a QMainWindow it goes through all sorts of machinations to remove it from the MW layout, change the widget's window flags, remember the old position in the layout, and so on. And the reverse to dock it again.
To do what you describe (drag widgets arbitrarily around a window) you would need to not use a QLayout and position the widgets manually by specifying a QWidget::setGeometry() for example. After initial position, and assuming the user has some way to grab the widget (title bar or drag handle you made, etc), you'll probably still need to manage their positions, for example if the main window is resized (if you care about keeping them contained). Essentially you'd have a bunch of separate widgets acting as individual windows and probably need some way to keep track of them.
I don't know what kind of widgets you're talking about, but one option may be a QMdiArea which lets the user drag windowed widgets around, tabify them, save/restore state, and so on.
For more flexibility you could also look into the Qt Graphics Framework. The graphics scene has a lot of features for user-movable items/widgets, keeping track of them, and so on. It is probably the most flexible method overall, and you can also use regular QWidgets inside a graphics scene.
A couple other Q/A about arbitrarily positioning widgets (I'm sure there are more to be found):
QPushButton alignment on top another widget
How to keep Push Buttons constant in relative to change of Label Size in PyQt4
When I run my program it will display all content properly, and when I resizing the main window, the layout along with all associated widgets remain fixed, rather than resizing with the main window. I used to increase my all widget and listWidget respect to window computer resolution size but still this not one work properly.
I used this one code finding the system height and width.
QWidget widget;
widget.resize(widget.width(), widget.minimumHeight());
QRect rec = QApplication::desktop()->screenGeometry();
int h = rec.height();
int w = rec.width();
// Increasing the listwidget size
ui->listWidget->setFixedHeight(h);
ui->listWidget->setFixedWidth(w);
//increasing the button size
ui->pushButton->setFixedHeight(h0.2);
ui->pushButton->setFixedWidth(w0.2);
At this link you will find two screenshots that illustrate my problem.
Please resolve to solve my problem. Thanks very much in advance.
When defining the layout of your windows and forms in Qt Designer you have to define each element of your form in advance, in order to have a working layout.
This solution is based on the screenshots provided in the comments to the question. Follow these steps:
Add an empty widget to the central area of your form, if there is nothing there. It will be used as a placeholder for the controls you will add later, and of course you can replace it with whatever widget you want. But you need it there to define a proper layout.
In the property panel, set the horizontal QSizePolicy of this widget to MinimumExpanding.
Add an horizontal spacer to the left side of your progress bar.
Define a minimum/maximum width for the white widget on the left (I guess it's a text area). As an example set the maximum width to 200
pixels.
Make the same for the QTabWidget on the right.
Give a minimum height to the Groupbox on top.
Then give the grid layout to the MainWindow.
You should get something similar in the designer view (I use a dark theme, yours will have different colors of course):
If you complete all steps you should have a nicely resizing window.
For the future: remember to integrally define your layouts, also using placeholder widgets when needed, read carefully the documentation about the widgets size policies (there are several, you need to play with them to fully understand each one) and keep in mind that Qt uses a container based approach which is different, as an example from those used by the .Net framework that relies on the concept of anchors.
EDIT : to answer questions in the comments
You will need to add a layout to any widget that contains other widgets, e.g. adding controls to your groupbox will require to give it a grid, horizontal or vertical layout in order to scale nicely on resize. Again use spacers and size policies to make it look the way you want. If you need to add or remove controls, or change their positions, you may need to brake the layout, rearrange and then set it again.
You can also select groups of widgets and give them a layout e.g. vertical, than another group and set them horizontal and so on... then give a grid layout to the container widget to build a compound layout.
There are endless possibilities, you just need to practice and go through trial and error as for everything else...
You can also do it all programmatically, check the Qt widgets documentation for this. But for complex layouts I would not go that way: it's a lot of code... and you have to compile and run to test every modification.
Using the QtCreator, within the designer you can simply right-click on the parent-widget and add a Grid-Layout.
This one resizes it's children to it's dimensions.
I want to allow a user using my application to be able to drag a boundary between two widgets in my window which will resize the two (i.e. you drag it down and the top one will get bigger while the bottom gets smaller, and vice-versa).
Is there anything in Qt designer that will allow a user to resize an element in the window, within certain constraints?
Thank you
What you're describing is called a QSplitter widget. In Qt Designer, you can create one by selecting 2 or more widgets, and then clicking the splitter button on the toolbar at the top. It's in the same location as the layout buttons. It will place those widgets inside a QSplitter. You still need to place the splitter widget inside another layout. It will create a handle between them to let you resize the portion that each widget gets.
You're looking for the QDockWidget. It can do all that you described above and more. The user can dock the widget to different sides of the window, changing which widget is on the top or bottom. You can customize the minimum and maximum sizes, as well as default sizes.
I use grid layout (horizontal and vertical too). I like the fact that when resizing the window fills the entire window contents. but this extension is poorly managed. I often want to change the size of only one column in grid layout without changing the size of the window. such as in Windows Explorer. there are two columns - the left list of directories and their contents to the left to the right. and i can always press mouse button therebetween and pulling change the mutual sizes of columns in relation to each other.
how can I do this in Qt?
You need to use a QSplitter rather than a QGridLayout in this specific case (where you just want 2 widgets shown together). QSplitters are draggable.
You are looking for QSplitter
(The following is the procedure in the Qt Designer)
Group your widgets, and click Lay Out Horizontally/Vertically in Splitter
Put this group into another layout (QGridLayout, for example) to automatically expand it.
Congrats! Your Layout is now draggable(from step1) and expandable(from step2).
I am using qt designer and python. I want to make a layout where a user can drag widgets to control the size while at the same time scaling properly with the window. Basically all 3d modeling programs have this function, usually it has a top left right and perspective view. The user can drag the edges to resize each view and it will maintain that aspect ratio when the main window is resized. My question is similar to this: active resizing of widgets inside mainwindow but I would like to do it in qt designer.
So what I have found is the layout horizontal/vertical splitter. However I am only able to layout two widgets horizontally, and another two widgets horizontally, then grid layout. This makes it look similar to what I want except I want the top and bottom horizontal layouts to also be re-size able.
Thanks
Edit:
I have been able to do this with putting both horizontal split views in a group box and then splitting the two group boxes, however that makes each widget independent and does not let the user grab the middle axis to control all 4 views.
You are essentially asking for a splitter than works across two axes - no such standard widget exists. So you will have to create your own.