I want to add scroll bars to the frame container. the QscrollArea can only take on widget but in my frame I need many wigets
I tried to write a code for the bars after adding a horizantal and vertical one but It's too hard.Is there any pre-made free code I could use ?
thank you
QScrollArea can take any number of widgets - indirectly. The widget() can contain any number of child widgets, it can have a layout set, etc. See e.g. this answer.
Related
I am working on a hide/show feature for my console in my Qt GUI application. The console consists of 2 widgets; QLabel and QTextEdit. Do I need to add the QLabel and QTextEdit to a QWidget in order to show/hide them, or is there a better way?
So basically I am looking for a container such as 'JPanel' in Java...
Do I need to add the QLabel and QTextEdit to a QWidget in order to show/hide them, or is there a better way?
Multiple methods are possible here. You can, as you suggest, create a parent QWidget and add the QLabel and QTextEdit to a QWidget. Calling show and hide on the parent widget will affect its children.
Another method would be to have a slot function, which when an action is called, the slot calls show / hide on the 2 widgets.
Neither is right or wrong and depends upon the overall design of your application.
Ok, I think you need to use a layout (horizontal / vertical):
The simplest way to arrange objects on a form is to place them in a
horizontal or vertical layout. Horizontal layouts ensure that the
widgets within are aligned horizontally; vertical layouts ensure that
they are aligned vertically.
Horizontal and vertical layouts can be combined and nested to any
depth. However, if you need more control over the placement of
objects, consider using the grid layout.
I need to update the QSplitterHandle position when QSplitter child widget is resized due to other reason, than moving splitter handle. Particularly, I have the composite widget inside the splitter, and one of it's children is hidden.
I've tried the following things:
setting QSizePolicy to widget.
setting QSizePolicy to the other widgets in QSplitter
setting stretch factors to the widgets inside QSplitter
I've asked the same question at QT support center, and here is the answer:
Unfortunately there is no automated update function for handle position. The setSizes() function is a good option to update the sizes, but I can see the problem with recalculating the sizes every time. Another way is to implement your own splitter and call its protected function moveSplitter(). You still need to calculate the position where the splitter handle needs to be moved to, but you don't have to recalculate all widget sizes.
I currently have the following structure in my form
I have a QFrame (Brown) that has a QScrollArea . Now Multiple QFrames are dynamically added to the QScrollArea (gray).The dynamically added QFrame are composed of a QLabel.
Now here is the problem I have disabled the horizontal scrollbar in the QScrollArea . Thus the horizontal scrollbar does not show up. The problem is that when the dynamically added QFrame (gray) is added to the the QScrollArea. Half of the frame is cut off. This is because I have no way to scroll horizontally. What I want is to have the dynamically added Qframe expand vertically instead of horizontally. Any suggestions ?
Update :
I have a QVBoxLayout inside the QScrollArea
Set the proper horizontal size policies for your dynamically created frames while creating them. One option is fixed size (QSizePolicy::Fixed), the other is QSizePolicy::Maximum (it's not very intuitive, but actually maximum means that the frame won't be bigger than the size specified by sizeHint() function). If you want the widget to expand vertically, set the vertical size policy to QSizePolicy::MinimumExpanding or QSizePolicy::Expanding - whatever works for you.
In Qt, how can I have a widget which automatically sizes itself according to the size of it's children?
For example, if I have a QGroupBox which contains a QHBoxLayout which contains some QPushButtons, I would like the QGroupBox to automatically calculate it's size so that it is no bigger and no smaller than necessary to fit all of the QPushButtons.
Ideally I would like to be able to do this in Qt Designer so that I can create a .ui file which already knows how to size the QGroupBox, however I am also opening to deriving from a class inside a .ui file and doing the resizing manually.
I have tried placing the QGroupBox inside it's own layout (with and without a spacer) but this just resizes the QGroupBox to the smallest possible size so that none of the children are visible.
There are two things to pay attention to:
Set the size policies appropriately on the children in the groupbox. You literally need to think what the buttons can do - most likely, you do not want the buttons to either grow or shrink, so setting both of their size policies to Fixed is the right thing to do. You could, possibly, let the buttons expand horizontally, so the horizontal policy of MinimumExpanding is an option.
Set the size constraint on the layout in the groupbox to act according to your objective:
ui->groupbox->layout()->setConstraint(QLayout::SetMinAndMaxSize);
Of course, the groupbox will be inside of some layout in its parent window, but that doesn't matter.
You'll probably have the most luck by sub classing QGroupBox and overriding sizeHint or other sizing functions to loop through children and calculate the minimum bounding rectangle. Depending on how dynamic the group box is, managing connections to new widgets might be a small challenge.
How do you change the behavior of a QListWidget so that it resizes its height instead of choosing a (seemingly arbitrary) height and adding scrollbars? See screenshot:
The QListView's should fill up as much space horizontally as they can (creating as many "columns," if you will.) Then they wrap and make as many rows as necessary to fit all the items. These calculations should be adjusted as the window is resized. This is all working fine.
However, what I want to happen is that instead of the height staying the same, the QListView should grow or shrink vertically and never need any scrollbars. The scrolling, if necessary, will be handled on the parent QWidget that hosts all of the labels and lists. It seems like once the height of the QListWidget is established (not sure where its default is coming from), it never changes. It is too big in some cases (see second "Test" list above) and too small in others (see first "blank maps" list above.)
The layout above is nothing surprising: two QLabel's and two QListWidget's in a QVBoxLayout. Here are the properties I have set on the QListWidget's:
setMovement(QListView::Static);
setResizeMode(QListView::Adjust);
setViewMode(QListView::IconMode);
setIconSize(QSize(128, 128));
(I already tried setting the horizontal and vertical scrollbar policies, but that just turns the scrollbars off, clipping the content. Not what I want.)
Maybe you could this without using QListWidget. The Qt's examples contain a new layout class, QFlowLayout, which could be useful. With the following kind of widget hierarchy you could get multiple groups with labels and they all would be inside one QScrollArea.
QScrollBox
QVBoxLayout
QLabel "Blank maps"
QWidget
QFlowLayout
your own widgets showing map images and labels
QLabel "Text"
QWidget
QFlowLayout
your own widgets
The problem is that this kind of solution would create much more widgets than QListWidget based solution. So if you have hundreds of items in your list, this might not be the best solution.
There is a protected member function called contentsSize() in QListView. It is used to calculate the required minimum(), maximum(), and pageStep() for the scrollbars (as mentioned here).
Can you subclass the QListView class and make use of that information? I suggest you recalculate the size of your widget in the same function where you add contents to it. While somewhat lacking elegance, this appears to be a pretty reliable solution.