Here is the environment first:
I have a self defined "Property Editor" which is a QGroupBox (derives from QWidget)
Currently I have a class let's call it "Holder", which has a reference to two of the Property Editors.
Now I have multiple "Holder" classes and one vertical QVBoxLayout (called Sidebar).
In this layout I want both of the Property Editors of the currently selected Holder class to be displayed.
And there is the issue:
When the user selects another holder class, I want the Property Editors of the previously selected Holder class to disappear, and add the Property Editors of the new selected Holder class.
Selecting another Holder class works once. But when I select the first Holder class again, The editors don't seem to change. Why? Does "takeAt(..)" destroy the reference in the holder class? How can I get the desired behavior?
Here is the code, thanks in advance:
void App::setSelection(Holder * holder){
if(m_currentlySelected == holder) return;
m_viewer->sideBarRemoveAt(0);
m_viewer->sideBarInsertAt(0, holder->firstPropEditor);
m_viewer->sideBarRemoveAt(1);
m_viewer->sideBarInsertAt(1, holder->secondPropEditor);
m_currentlySelected = holder;
}
void QtViewer::sideBarRemoveAt(int i){
m_sideBar->m_layout->takeAt(i);
}
void QtViewer::sideBarInsertAt(int i, QWidget * widget){
m_sideBar->m_layout->insertWidget(i, widget);
}
QLayout::takeAt() doesn't remove the widget of the QLayoutItem from its parent widget. The only reason it may seem to work the first time is probably because the other widgets were above (z-index wise) the first ones.
Rather than playing with the layout, you could
just hide/show your 2 PropertyEditor whenever the holder changes, hidden items don't generate holes in the layout, the next visible item is displayed as if the hidden items were not part of the layout, or
use a QStackedWidget to stack all the PropertyEditor at the same place and select which one is displayed (with QStackedWidget::setCurrentIndex()).
Does "takeAt(..)" destroy the reference in the holder class?
No, this method removes the QLayoutItem from the layout. See reference page for takeAt. This class doesn't release the layout item (it is your responsibility to do).
But when I select the first Holder class again, The editors don't seem
to change. Why?
I am not quite clear what you are trying to achieve (not enough code in your example), but if you are trying to change the layout using QLayoutItem's, then it is the simplest to create new layout and add items you want to display to it. Or simply, remove all items from the layout, and add the items that should be visible.
Related
The application that I'm building is supposed to create, destroy, and manipluate widgets that I've created
The problem is I'm not making a simple program with nice buttons where everything is symmetrical and needs to be evenly spaced and handled via a layout that will automatically move everything around and space it.
And yet, the only way I know of is to manually instance a layout and add the widgets to it, but then I can't set the coordinates of them
How can I simply instance my widget, and add it to the project generated frame?
This is how I'm instantiating my class, in which case I then set my own parameters:
Tile *tile = new Tile;
tile->setImg("://Images/placeholderTile.png");
tile->setCol(true);
tile->setGeometry(retX(line),retY(line),50,50);
To reiterate, I want to add my own widgets to a frame outside of the editor (only by code), and be able to manually move them around the frame by code.
I don't see an ".addWidget() as a method accessible from the QFrame, and yet they can be children within the designer, why can't I do this by code? Whenever I try to do it manually and add them to any layout, any attempt I make to manually set the widgets location doesn't do anything. I haven't overridden the setGeometry
I fixed my problem
After 2 hours of continual searching I finally came across my answer
I never thought that you could set the parent of a widget by code, as I thought you strictly had to add it in as a child of something else, not the reverse and declare that it should have a parent
So, by simply adding the line:
tile->setParent(ui->frame);
completely fixed my problem.
I will change this post back and submit the answer tomorrow when I'm allowed to by this site.
Thank you to those who actually came though. I'm just glad I managed to fix it before that.
All you need is to pass the parent to the widget's constructor:
Tile *tile = new Tile(ui->frame); // <-- here
tile->setImg("://Images/placeholderTile.png");
tile->setCol(true);
tile->setGeometry(retX(line),retY(line),50,50);
Since Tile is your own class, you should definitely have a Qt-style, parent-taking explicit constructor for it:
class Tile : public QWidget {
...
public:
explicit Tile(QWidget * parent = 0) : QWidget(parent) { ... }
};
Another approach is to write your own layout that would know about the relationships that are to be held between your objects. After you do it once, writing custom layouts isn't that hard.
This questions to me reeks of maybe a lack of understanding of C++, as the possibilities I've considered for my problem all seem to make no sense on why this could be occuring. Feedback appreciated.
I'm using the form designer to create a form class with a table in it. I'm trying to replace the table with another table generated in a helper class. I'm only doing this so I can (hopefully) maintain the nice grid layout I've designed, and through pointer manipulation, get the replacement I desire. Here's some code snippets from the table form constructor and relevant calls :
//tableData is defined in the header file as a QTableWidget*
tableData = this->findChild<QTableWidget *>("tableData");
....
setup();
void setup(){
tableData = Utilities::createTable(this->file, tableDelim);
//createTable returns QTableWidget*
... other assignments, and label text updates, which seem to all work
}
My understanding is that tableData is a pointer, and if printed, will give the address of the QTableWidget from the layout. So then if I create a QTableWidget* and then assign tableData to that, tableData should now point to the new widget. Instead, I see only a blank screen.
I tried checking what the tableData pointer is before I assign it to the new QTableWidget*, and after. The second pointer shown is what is generated by createTable() :
QTableWidget(0x101272d40, name = "tableData") QTableWidget(0x10127b3b0, name = "test_sample2.nuc.stats")
QTableWidget(0x10127b3b0, name = "test_sample2.nuc.stats") QTableWidget(0x10127b3b0, name = "test_sample2.nuc.stats")
It seems the pointer is being reassigned, but the table drawn isn't the right one.
What gives?
My understanding is that you want to design the table layout in designer but fill in the data from an external source.
I would suggest, to just use the QTableWidget that is created in setupUi() and modify Utilities::createTable() such that it becomes Utilities::populateTable(QTableWidget & table, <all the other parameters you need>). (Or use QTableWidget * if you prefer - however I like putting the non-zero assertion responsibility on the caller...)
Apart from that, I agree with Sebastian Lange.
You are right with your assumption. You do set a variable to be a pointer to a object and next you set the variable to be a pointer to another object. You never change any objects, just your variable which is not used to display anything.
You would need to do something like:
//tableData is defined in the header file as a QTableWidget*
tableData = this->findChild<QTableWidget *>("tableData");
parentLayout = tableData->parent()->layout(); //Get the parent widget to add another table.
parentLayout->removeWidget(tableData);
delete tableData;
parentLayout->addWidget(createTable());
You need to use pTheContainerOfTheOriginalTableWidget->addWidget(tableData); See here: http://qt-project.org/forums/viewthread/16547
Be sure you remove the original tableWidget so you don't have two (I assume you don't want two).
If I understand you correctly we have such situation.
call of setupUi (which generated by qt tootls),
there there is something like this(pseudo code):
oldTablePtr = new QTableWidget(parent);
someLayout->addWidget(oldTablePtr);
So parent and layout hold value of oldTablePtr.
And if you set variable oldTablePtr nothing changed.
parent send QPaintEvent to oldTablePtr.
So you need call delete oldTablePtr, that remove this widget from list of childs of parent, and move newTablePtr to the same layout.
There's no need to replace it in code, you can do it in Qt Designer. Just place QTableWidget on form, then rightclick it and choose Promote widget in menu, then you will need just enter your classname.
Currently I don't have Qt Designer near me, so edits will be appreciated.
What I'm trying to accomplish:
Create 2 classes that inherit QVBoxLayout simply to set up each class with a series of different objects.
e.g.:
Class 1 (inherits QVBoxLayout), has QLabels to show an appointment and those labels set up with this->addWidget(labels);
Class 2 (inherits QVBoxLayout), has QLineEdits (and so on) to edit an appointment and those objects are also set up with this->addWidget(lineedits);
Is it possible to have a QWidget class then switch between these 2 layouts by calling this->setLayout(class1_object); and this->setLayout(class2_object);?
Or how would you suggest the swapping of the active objects on the widget (when clicking the edit button on the view-part or the save button on the edit-part)?
Simply use object->setShown(false);?
IMO, it's easier to use QTabWidget here.
Make a QTabWidget with 2 tabs. On Tab1, put your labels. On Tab2, put your edits. Call Tab2 something like "Edit the appointment". Now, use the currentChanged() slot for catching the tab switching.
If saving edits should be simple, all you will need to do is just to copy the edited data from edits to labels, and vice-versa.
If saving requires more than that, e.g. you want a confirmation dialog, you can permit the user to change back to Tab1 until some condition is met:
void MainWindow::on_tabWidget_currentChanged(int index)
{
//if the user is trying to go back to Tab1 (where the labels are)...
if(index == 0)
{
//...and if user didn't accept something, we just return him to the current tab
//It's probably a good idea to tell him what went wrong, too :P
if(!userAcceptedSaveDialog())
ui.tabWidget.setCurrentIndex(1);
}
}
I found this question: How to change the background color for a QTreeView Header (aka QHeaderView)?
I want to be able to set the color for each header section. So the question seen above seems to be my solution!
The solution says "the easiest way to do that is probably to derive a new model from QAbstractItemModel or another model class and reimplement the headerData()". I went and looked at the Qt source tree for QTableWidget, QTableModel, QTableWidgetItem... these classes are supposedly "default models" so I thought they would be a good example and then I would go implement my own QAbstractTableModel.
The 3 files I saw are a whopping 3300 lines of code. That is definitely NOT "the easiest way" IMO!!!
I would like the functionality of QTableWidget but then I want to add the following ability:
horizontalHeader.setSectionColor(index,color)
verticalHeader.setSectionColor(index,color)
Do I really need to inherit/implement QAbstractTableModel if all I want is to change the color of a section header?
Update:
I am not using my own custom view and model classes. I am using the convenience class QTableWidget right now (it is called a convenience class b/c it implements the view and model). The function headerData() is part of the model. The model class, QTableModel, is not accessible via Qt lib/headers so I can't inherit from it.
Update:
I tried creating a new item with background brush QBrush(QColor(Qt::red)) and then setting the table's header with the new item (using QTableWidget::setHorizontalHeaderItem(int column, QTableWidgetItem *item). I also tried inheriting QTableWidgetItem and overriding the virtual data() method with:
QVariant HeaderItem::data(int role) const
{
if(role==Qt::BackgroundRole) {
return QVariant(QBrush(QColor(Qt::red)));
} else if(role==Qt::ForegroundRole) {
return QVariant(QBrush(QColor(Qt::green)));
} else {
return QTableWidgetItem::data(role);
}
}
I can change the header sections foreground. But when I try to change the header's background brush... nothing happens... it's like the QTableWidgetItem's background brush that I set for the header section is ignored.
Instead of creating model with custom headerData() from scratch create subclass of QTableWidgetItem with desired implementation of QTableWidgetItem::data() and use the instances of this class for QTableWidget::setHorizontalHeaderItem.
Ok so I have been going insane trying to find an answer to this for a day now. What I am trying to do is make a copy of all the widgets in a tab. I want to transfer the copy to a new tab. Think of a form in a tab, and when you click "New Tab" it displays the same form but blank. I am new to QTCreator so any pointers would be great.
Thanks in advance!
Any class that derives from QObject is not copyable. If you want to "copy" a widget, then perhaps a model-view architecture would be a better fit where you have two different views representing the model.
Another thought: you could have each class that needs to be copyable create a state object that could then be used to set the state on the copy.
Since you're just trying to display the same form in multiple places, you could do something like this.
First, create your form which I'll assume is called MyForm:
class MyForm: QWidget {...};
Then, in the parent form:
void ContainerForm::ContainerForm(...) {
connect(pbAddNewTab, SIGNAL(clicked()), SLOT(addNewTab()));
}
void ContainerForm::addNewTab() {
tabWidget->addTab(new MyForm(this));
}
You may need to pull out the new so you can setup signals and slots, etc.
If the new form is blank then it is not a copy. All you need to do is create a new instance of your form widget.