My intention is to provide a GUI with two sections, one of which displays k buttons, where k is the number of .txt files in a specific folder. I would be glad to know that there is a way to to simply add buttons (largest possible), still “nicely” arranged in a full screen window. In other words, I would like to only add push buttons, and these would be automatically arranged for me (no specification of coordinates and sizes).
The initial window should be full screen, and buttons should be as large as possible. Any description on how this might be achieved, with pointers to existing examples, is highly appreciated.
You should look into Qt Layouts, for exactly this kind of problem.
A simple example might look something like:
QStringList myListOfFiles;
QWidget *parentWidget; // The widget you want to put them into
QVBoxLayout *layout = new QVBoxLayout;
foreach(QString file, myListOfFiles)
{
QPushButton *button = new QPushButton(fileName,this);
layout->addWidget(button);
}
parentWidget->setLayout(layout);
This will arrange the buttons in one vertical column, and will be as wide as the parent widget. You could look at QGridLayout if you need more than one column.
Related
I'm trying to get an QMdiSubWindow to become the smallest size possible after generating the widgets.
Base .ui looks like this:
I then add a raster of widgets (checkboxes and lineedits) in the selected layout.
The window then renders quire relax with large line widgets. I can manually shrink the window to become almost half of what was initially shown.
How can I shrink the window automatically to the minimum sizes of the containing widgets?
I've tried playing with the sizepolicy, they either fix the widgets size, or make it larger...
The only thing that seems to be correct is the minimumSizeHint(), but there seems to be no way to apply that to a QMdiSubWindow? The resize() function does nothing.
You can't change the QMdiSubWindow size from within the widget it renders if you create the mdi windows like this:
QMdiSubWindow *subWindow = new QMdiSubWindow();
MyWidget *widget = new MyWidget(this);
subWindow->setAttribute(Qt::WA_DeleteOnClose);
subWindow->setParent(ui->mdiArea);
subWindow->setWidget(widget);
subWindow->show();
When you add subWindow->resize(subWindow->minimumSizeHint()); it works fine!
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
I have a small problem with QT layout.
I have a toolbox, and I want to populate it with some checkable buttons with a description. So I create a QWidget with a QGridLayout and put the QButton in the first cell and the QLabel in the second.
This is the most important part of the code (I removed dependancies from other irrelevant code in the app):
QWidget *createCellWidget()
{
QToolButton *button = new QToolButton(this);
button->setCheckable(true);
button->setMinimumSize(57,57);
button->setMaximumSize(57,57);
QWidget *widget = new QWidget(this);
QGridLayout *layout = new QGridLayout(widget);
layout->addWidget(button, 0, 0, Qt::AlignHCenter);
QLabel *lbl = new QLabel("my very long caption");
lbl->setWordWrap(true);
lbl->setAlignment(Qt::AlignCenter);
layout->addWidget(lbl, 1, 0, Qt::AlignTop);
widget->setMaximumWidth(80);
widget->setMinimumWidth(80);
return widget;
}
then I create a QGridLayout and populate it with these controls:
QWidget *itemWidget_FlowControl = new QWidget(this);
QGridLayout *_flowControl_layout = new QGridLayout(itemWidget_FlowControl);
_flowControl_layout->addWidget(createCellWidget(), 0, 0);
This works well and produces this output:
this is a nice layout. Unluckily if I enlarge the window the controls do not "flow", so I tried to replace the QGridLayout with a flowlayout (here are the source files).
Now the behavior is much better. BUT...
this is what I get. The longer captions are laid out as if they were single-lined, so the text overlaps with the button.
What can I do to make it look like before, but keeping it as a "flow layout"? Or do you know if there is any alternative in QT 5.2?
Thank you
What's wrong?
You are on the right track of using flowlayout.
The only problem is the internal layouts (QGridLayout in your case) of your cell widgets also stretch in response to the resize events.
Solution
The solution is surprisingly simple:
Try to limit the stretch of the internal layout.
Within the factory function QWidget *createCellWidget():
[Option 1]
Add lbl->setMaximumWidth(60); to manually limit the stretch of label width. This makes the internal layout not stretch so "freely."
[Option 2]
Add layout->setSizeConstraint(QLayout::SetFixedSize); to restrain the internal layout stretch. By doing this, you may want to manually add some line break code (\n) to your "very long caption" in case the label width automatically decided by Qt doesn't suit your need.
Result
IMO the best approach would be use off style sheets (flow layout is Ok).
Simply use QButton but customize its view by altering its stye sheet.
Currently I have no time to write an example.
In Qt: I create a widget-ui class, and I want to make the widget appear in two different layouts in two separate base widget(or window). So I want to:
widget_based_class* inside = new widget_based_class(base_widget1);
QHBoxLayout *lay1=new QHBoxLayout(base_widget1);
base_widget->setLayout(lay1);
lay1->addWidget(inside);
base_widget1.show();
-------------------------------
base_widget1.hide();
QHBoxLayout *lay2=new QHBoxLayout(base_widget2);
base_widget->setLayout(lay2);
lay2->addWidget(inside);
base_widget2.show();
How cound I achieve this? (My program is more complicated, and I didn't see the code work.)
Tank you.
A QWidget has only one parent widget and only one geometry (position and size) in that parent. Every call of QLayout::addWidget() will reparent that widget to the widget, the layout is installed on.
Your second call of setLayout won't work as expected, because you have to delete the the existing layout manager before setting the new one:
delete base_widget->layout();
base_widget->setLayout(lay2);
If base_widget hasn't already got a layout manager, the layout manager lay2 would simply be reparented.
If the widget will never be displayed twice on the screen, I don't see why you can't reparent it by addWidget/removeWidget.
In the OP, the parent widget/window is always hidden before the other one is shown. addWidget is called on the fly. We should also call removeWidget on the fly. It should be possible to move the widget around.
widget_based_class* inside = new widget_based_class(base_widget1);
QHBoxLayout *lay1=new QHBoxLayout(base_widget1);
base_widget->setLayout(lay1);
lay2->removeWidget(inside); // remove widget from other layout
lay1->addWidget(inside); // add widget to this layout
base_widget1.show();
-------------------------------
base_widget1.hide();
QHBoxLayout *lay2=new QHBoxLayout(base_widget2);
base_widget->setLayout(lay2);
lay1->removeWidget(inside); //remove widget from other layout
lay2->addWidget(inside); // add widget to this layout
base_widget2.show();
Make one widget and use a pointer in each layout?
I want to do universal method to set position of my widget.
All I wanna get it is set right coordinates for my widget wich must always be in right bottom corner of desktop. My widget can change his height (or maybe width) but it must have adjusted size by both ordinates... (too many words)
My idea is using QDesktopWidget as basic widget to put into my QLayout with stratch items (to align inner (my) widget to right and to bottom sides)
my code prototype is here:
QDesktopWidget * desktopWidget = QApplication::desktop();
MyWidget * myWidget = new MyWidget(desktopWidget);
QVBoxLayout * vlayout = new QVBoxLayout;
vlayout->addStretch();
vlayout->addWidget(myWidget);
QHBoxLayout * hlayout = new QHBoxLayout(desktopWidget);
hlayout->addStretch();
hlayout->addLayout(vlayout);
but it doesn't work...
Help me please implement my idea if you know how.
At this moment I know only one work way to do it - it is manually set pos of widget and handle many events (resize etc.) - but this is not good... (because i do it bad of cause ;-)
)
PS: idea with qlayout inside other widget is working for example with QTextBrowser with sandclock at certer of view, etc.
A QDesktopWidget isn't intended to be used like a typical widget (at least as far as I'm aware, I'm surprised the documentation isn't more explicit about that). So you shouldn't try to parent widgets to it or try to assign it a layout. You call its methods to obtain information about the desktop environment or connect to its signals to be informed of changes.
Using this information, you would then set the geometry of your own application widgets so that they appear on the correct screen and position you want.
This page shows some basic functionality.