Currently having a problem with Pyqt as we need to delete the content of a layout that we cannot find.
This is basically what we have :
<Layout1>
<Widget1>
<Layout2>
<Widget2>
...
We didn't have the Layout2 at first, and we didn't want to do
Widget1 = Widget2
So we add a Layout (Layout2), but as we are trying to change the content of Widget1, we have a class re-designed by ourself (that Looks like Qtdesigner generator), with a setupUi method with the Widget1 in parameter :
class ... :
def setupUi(self, Widget1):
#Creating Layout2 with Widget1 as parent
#Creating Widget2 with Widget1 as parent
#Adding Widget2 to Layout2
...
When adding the content of Widget1 to Widget1, we have no problem. Then we need to change the content and so we need to delete everything in Widget1 ( Well, we supposed that deleting was the solution ).
So here is the problem : When deleting the all stuff, we could not delete a mystical link between the 2 layouts. So we got messed up by the all thing and we're currently completely lost. We've been trying to use parent/children methods but we can't even get what we want...
So as I said :
How can I simply delete all Widget1 content and actually how to remove the Layout2?
We worked it out as I missed a line in the code of my collegue.
He was adding layout 2 to layout 1 and that was the problem.
So Layout just needs the children to be added to it.
Related
I recently decided to create a small application that simply reads the files in a compressed file and renames them. I went through several UI modules and decided to use PyQt6.
To achieve this, I first created a QWidget that holds the widgets QPushButton and QLineEdit.
The user then types the new name into the QLineEdit widget and select the QPushButton if the file has to be excluded.
Now, this widget that was created will be added into a QVBoxLayout which is then set as the QScrollArea layout.
Here's my problem:
Once I was done creating the scroll area and the list, I wanted to retrieve the content of each widget. For this purpose, I use the findChild method. But it only returns the address of the object.
Is there any way to get the text stored in QLineEdit of each widget? Is it possible to retrieve the text just by knowing its address?
Here's what I tried:
for index in range(self.layout.count()):
widget = self.layout.itemAt(index).widget()
nameFromLineEdit = widget.findChild(QLineEdit).text()
print(nameFromLineEdit)
In PyQt, I have a dialog that spawns another dialog (when you click a button to do so in the first dialog). I want to maintain a strong parent-child relationship, for garbage collection purposes, and to make the .findChild and .findChildren functions usable.
The root of the question may be: how do you use .setParent() but still have the object in question be shown as a separate window, rather than shown within the parent widget?
The 'parent' dialog (actually a container widget within a tab within a dialog) is 'newEntryWidget'. It spawns 'clueDialog' when a signal (not shown here) calls newEntryWidget.quickTextClueAction as a slot. Visually, clueDialog should be a "top level window" with its own banner, its own window attributes (I want to keep it on top of everything else), etc.
class newEntryWidget(QWidget,Ui_newEntryWidget):
def __init__(self,parent,sec=0,formattedLocString='',fleet='',dev='',origLocString='',amendFlag=False,amendRow=None):
QDialog.__init__(self)
self.parent=parent # just an attribute; not the same as setParent
...
...
def quickTextClueAction(self):
self.newClueDialog=clueDialog(self,self.ui.timeField.text(),self.ui.teamField.text(),self.ui.radioLocField.text(),lastClueNumber+1)
self.newClueDialog.show()
class clueDialog(QDialog,Ui_clueDialog):
def __init__(self,parent,t,callsign,radioLoc,newClueNumber):
QDialog.__init__(self)
self.parent=parent # just an attribute; not the same as setParent
...
...
Right now, since I am using self.parent=parent, which is just an attribute and not true "parent/child relationship" in Qt terms, clueDialog does display as a top level window, which is what I want:
But, if I add 'self.setParent(parent)' in the clueDialog init function, I get this:
How can I preserve the top-level-window behavior, and have the real-honest-parent-child-relationship so that .findChild(clueDialog) will work from within the newEntryWidget object?
Ultimately, I want to enforce that the newEntryWidget object should not be closed if it still has and 'child' clueDialogs open.
Instead of calling .setParent, call QDialog.__init__(self, parent) which constructs the clue dialog with a parent from the beginning. Setting it this way allows Qt establishes the parent-child relationship at the beginning of clueDialog's lifetime.
I believe this will fix both your issues: 1) the clue window frame, caption, etc. will be painted, 2) you will be able to iterate for proper children of newEntry.
I am attempting to write my first program using Qt5. I found a tutorial (zetcode.com/gui/qt5) with a number of examples, which all used dynamic layout creation. I'm trying to create a nested layout configuration, but I'm having a problem with specifying the parent parameter of the layout constructor. When I use the main window as the parent for the main layout and its sub-layouts, I get an error message, apparently telling me that QWidget can have only one QLayout. The window looks OK, but I haven't implemented all my functionality yet (slots and other code), so I don't know what, if anything, is broken. If I omit the parent parameter from the sub-layouts, I get no error messages and the window looks OK as well, but again I'm wondering whether this would affect my subsequent code additions.
Can anyone explain to me the significance of a layout's parent? I've noted that specification of the parent window in the layout's constructor is apparently not sufficient, because all of the examples I've seen call setLayout() at the end of the window's constructor. In particular, will my omission of a parent ever cause problems?
The "rules" are that there can be at most one top level layout on a given widget, and that widgets can be only children of other widgets, not of layouts. So what happens is that:
when you set a layout on a widget, the widget will take ownership of that layout;
when you add widgets on a layout, these widgets will be reparented to the widget the layout is/gets installed upon;
when you add a layout inside another layout, the inner layout becomes a child of the outer layout.
What you're probably seeing is a side-effect of creating a layout with a widget as parent, as in
QLayout *layout = new SomeLayout(widget);
This will try to install the layout on widget, and fail in case there's already one. The good news is, you can pretty much ignore passing parents around and rely on the system to do "the right thing". For instance:
MyWidget::MyWidget(QWidget *parent)
: QWidget(parent)
{
QHBoxLayout *mainLayout = new QHBoxLayout; // top level layout
QVBoxLayout *subLayout1 = new QVBoxLayout; // sub layout 1 stuff
QPushButton *button = new QPushButton("button");
subLayout1->addWidget(button);
// create more widgets...
mainLayout->addLayout(subLayout1);
QVBoxLayout *subLayout2 = new QVBoxLayout; // sub layout 2 stuff
QLineEdit *edit = new QLineEdit;
subLayout2->addWidget(edit);
mainLayout->addLayout(subLayout2);
setLayout(mainLayout);
}
This will correctly create a layout hierarchy and a parent/child relation so that nothing will get leaked.
Background/Context:
I have a HBox as a parent and many child Nodes (Buttons, TextFields, Labels…). The HBox is a child of other container (BorderPane/VBox/Grid)
My questions:
How do I dynamically remove/exclude the parent (HBox) and all its children from layout?
I am looking for some three-state property on Node (like in Microsoft WPF):
Visible – visible and participate in layout
Collapsed – is not visible and do not participate in layout (applies to its children as well)
Hidden – is not visible but participate in layout
http://msdn.microsoft.com/en-us/library/ms590101.aspx
What options does JavaFX offer?
My solutions so far:
hBox.setManaged(false);
this work only for HBox, its children are still present
root.getChildren().remove(hBoxTop);
root.getChildren().add(hBoxTop);
Well, this looks like it could work.., but for example in case of root being BorderPane, once I remove/add and remove the HBox, the space after it remains unused. I already tried requestLayout() but id does not force thr rrot to fill it. Am I missing something? Is it correct approach to this problem?
Edited:
Well, I got this working.
Dynamically removing and adding for this specific case can be achieved by:
Remove:
root.setTop(null);
Add:
root.setTop(hBoxTop);
When I did not call setTop(null) on removal, BorderPane still reserved space for HBox (even after removal from its children).
IMHO: it is not very good model as it is parent-container specific. For example if I change, BorderPane to VBox a I had to change these methods as well. For VBox, remove/add on children collection works but I need to remember index so that HBox appears at same place after calling add.
Using root.setTop(null) is not a good idea because as you say it's specific to BorderPane.
I think the best solution is to use:
root.getChildren().remove(yourPane);
And use layout methods to place your other childrens as you want.
But maybe you should not use a BorderPane in the first place with the behaviors you want in your application.
Notice you can also do root.getChildren().clear() to remove all component and add it again to your layout but differently.
I have two custom widgets (two classes based on QtGui.QWidget). In __init__ of QtGui.QMainWindow I create their instances:
self.MyWidget1 = MyWidget1()
self.MyWidget2 = MyWidget2()
There are also two buttons (QtGui.QPushButton) in __init__ part, and there are two slots when user clicks each of them:
def clickButton1(self):
self.setCentralWidget(self.MyWidget1)
def clickButton2(self):
self.setCentralWidget(self.MyWidget2)
But it works only on first click and then PyQt says that underlying widget (MyWidget1 or MyWidget2) was deleted. I think it was done by sip module. Is there a way to prevent deleting widgets after reseting of central widget? Thanks!
I think it's almost impossible.
From setCentralWidget docs:
Note: QMainWindow takes ownership of the widget pointer and deletes it at the appropriate time.
So, you should create new MyWidget instance.
def clickButton2(self):
self.setCentralWidget(MyWidget2())
But the right way of doing such things is to use QStackedWidget