I'm working on a project where i have some qpushbuttons and some QlineEdit using qt c++. I want to choose in which QLineEdit my text should be appear. As far I put some text only in the first QLineEdit and the other is filled by condition depending on the first
QInputDialog is a way to get user input.
And I think you need QInputDialog::getItem to choice one of many things.
So I have QFormLayout that manages my QLabel-QLineEdit pairs just fine.
Problem is, that I need to achive something like this:
Horizontal border/tittle isn't a problem, but "Street"-"Apartment"/"Post code"-"City" pairs are.
So my question is: how to add two pairs of QLabel-QLineEdit as one row to QFromLayout?
If it's not possible with QFormLayout, do you have any suggestion about achivining the same with other layout (QGridLayout, I guess)?
Keep in mind, that labels can have different size proportions after translated to other languages.
Thanks in advance!
Thanks for all the response!
I've ended up adding QLabel as label and QHBoxLayout with QLineEdit, QLabel and QLineEdit as field to QFormLayout.
Something like:
QLabel firstLabel, secondLabel;
QLineEdit fisrtEdit, secondEdit;
QHBoxLayout hBoxLayout;
hBoxLayout.addWidget(firstEdit);
hBoxLayout.addWidget(secondLabel);
hBoxLayout.addWidget(secondEdit);
QWidget container;
container.setLayout(hBoxLayout);
myFormLayout.addRow(firstLabel, container);
do the trick!
Also, if you're planing to add more than one row like this, I'll need to set all secondLabels to one fixed width. I did this by iterating over all secondLabels twice: first time for finding maximux width and second for setting this width to all of them.
A bit hacky, but I couldn't find a better way so far. Solution with QGridLayout would be even more complicated, on my opinion.
I think you should create a QWidget with get a Vertical layout with the QLabel and the QLineEdit then add the label in the QFormLayout. I don't get the time to show you an example but think about to create an ui with a QLabel-QLineEdit in a QVBoxLayout.
By creating an ui you can add any widget in with the same form easily.
So you mainWindow. you main layout -> create your widget -> add vertical layout -> add your QLabel and QLineEdit to yout widget layout -> add your widget to your main layout.
I think you should show a QtCreator-QtDesigner tutorial. It will take you some time but you will get really faster after.
If you want to add a label without the QLineEdit to appear, you can define a QlineEdit and hide it:
(the code is in python, just to show the principle)
self._dummy = QLineEdit(self)
self._dummy.hide()
layout = QFormLayout(self)
layout.addRow("text without an edit field", self._dummy)
Here is a method I just created for my solution, this is a pseudo code version that might help someone.
def create_gb_f(self):
gb = QGroupBox("F")
ly_horiz = QHBoxLayout()
layout = QFormLayout()
layout.addRow( label, edit)
ly_horiz.addLayout(layout)
layout = QFormLayout()
layout.addRow( label, edit)
ly_horiz.addLayout(layout)
ly_horiz.addWidget( button)
gb.setLayout(ly_horiz)
return gb
First let me explain what I'm trying to achieve:
In your browser, hit Ctrl + f and type "q". The result of that operation is what I'm trying to achieve. It seems like this should be a solved problem, but despite the many hours I've spent researching, reading documentation, and asking around in the Qt IRC, I'm still stuck. Maybe somebody here will be able to give me a hand.
The following Qt classes are what I'm currently dealing with, in case you want to brush up a bit.:
Qt::DisplayRole
QModelIndex::data
QAbstractItemView::setDelegate
QTextEdit::setExtraSelections (only as a reference)
QAbstractDocumentLayout::Selection
QTextDocument::drawContents
QStyledItemDelegate::paint
QStyleOptionViewItem
QStyleOption::rect
QTableView
QAbstractItemModel::match
Learn to Model/View Program with Qt
So now, let me explain how I have things set up, and what the results of my research and interactions with the Qt IRC has lead me to believe I should do.
I am using a QStandardItemModel along with a QTableView. Each row that gets appended to the QStandardItemModel has several columns. As we know, each of these columns is represented in the QStandardItemModel as a QModelIndex. We can pull its displayed text by accessing its data(Qt::DisplayRole).
Conveniently, given a search string, QStandardItemModel::match will return a QModelIndexList of every QModelIndex that, well, matched in the column. Of course, if you have several columns in every row, you would need to preform this match over each column, but I can worry about performance here later.
So cool, that problem is solved. We have our list of every QModelIndex that had a matching string. Now, what I want to do is highlight that string in each column. For example:
Search string: "col"
This is a column | This is aColumn | This is aColumn | This is a co
Parts that would appear highlighted are what I have in bold above. In order to achieve this, I knew from reading the Model/View docs that I needed to subclass a QStyledItemDelegate and reimplement its paint function. So I started there.
The next problem to solve would be, how in the world to select a specific piece of text in the DisplayRole and only highlight it? You can't use Qt::BackgroundRole, that would set the entire index's background color. Enter QTextDocument.
I still need to do more digging to see how exactly I can implement that behavior, but from what I was told in Qt IRC, QTextEdit has a function called setExtraSelections. Looking at how that is implemented, it leverages QAbstractTextDocumentLayout::Selection and various cursor functions available to me in QTextDocument.
However, sadly I cannot even begin to solve that problem, because the first step is to actually ensure that I can render a QTextDocument to the QTableView with my reimplemented custom delegate paint function. This is where I'm stuck currently. I've seen this post, here and the one it references:
Similar question that doesn't solve my issue
Its not exactly what I was looking for, but I figured it would help me at least get something rendering. It looks though like in his code, he's drawing the control (which is literally what QStyledItemDelegate does), and then tries to paint his QTextDocument over it. Maybe that's not what that is doing but it sure looks like it.
In any case, when I tried that, it looked like the QTextDocument had no effect. If I commented out the drawControl call, then no text would be rendered at all. Here is my code for that:
void CustomDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
QStyleOptionViewItem opt = option;
initStyleOption(&opt, index);
if (index.column() == contentColumn)
{
painter->save();
QTextDocument contentDocument;
//opt.widget->style()->drawControl(QStyle::CE_ItemViewItem, &opt, painter);
opt.text = "Things";
painter->setBrush(QBrush(Qt::darkCyan));
contentDocument.drawContents(painter, opt.rect);
painter->restore();
}
else
{
QStyledItemDelegate::paint(painter, option, index);
}
}
You can see I just typed text "Things" to see if I could just get that to render. To no avail.
Before summarizing my question I want to mention that no, I cannot use a QTextEdit. There are specific columns that I need to word wrap, while others I do not want to word wrap. QTableView displays the data exactly as I expect to see it.
So my question is this:
Is the QTextDocument rendering through the paint event of a subclassed QStyledItemDelegate the preferred way to handle this? If not, how else should I deal with it?
If so, how do I make it work as I expect? What is wrong with the code that I have?
Bonus 2 parter question
Once I can render, how can I actually leverage the QTextDocument API to highlight only specific pieces, given that the list of model indexes that contain the text to be highlighted is discovered in a completely different function and at a different time than when the paint function executes?
Update 0
Using the QTextDocument API to make multiple selections is looking like an impossible feat. The column that I would be drawing contents to needs to word wrap and expand.
From what I can tell, I calling drawContents manually means handling resizing, word wrapping, and many other things manually which is not a path I want to go down if that is indeed the case.
I've got another way in mind, I will update if it works.
Update 1
I have accomplished what I want in another way. Unfortunately, I cannot use Qt for what I want. Qt's Model/View system is entirely too inefficient and getting it to do what I need causes it to be extremely and unacceptably slow. How did I accomplish the highlighting?
I will describe in an answer. If nobody gives me a better answer, I will pick mine as the best.
I believe what you need to do here is override this method in your QItemDelegate subclass:
void QItemDelegate::drawDisplay(QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, const QString &text) const
The problem with QItemDelegate's implementation of this method is at the end, where we see this method call (it's actually called in two places, but since they are identical calls I'm just showing it once):
d->textLayout.draw(painter, layoutRect.topLeft(), QVector<QTextLayout::FormatRange>(), layoutRect);
It's that third argument that you'd want to change -- in QItemDelegate::drawDisplay(), it's hard-coded to always be an empty QVector, which means that all of the characters in the drawn text-string will be always have the same formatting. If you could somehow get it to be called with a QVector<QTextLayout::FormatRange> that contained your per-substring formatting preferences instead, you would get the effect you want.
Of course, the devil is in the details. If you don't mind hacking the Qt source code to fit your purpose, you could do that; but that would be an ugly solution since it would mean your program would no longer work correctly when compiled with a non-customized Qt release (and you'd have to re-patch every time you upgraded to a new Qt release).
So instead you'd probably want to start by copying the contents of the QItemDelegate::drawDisplay() method over to your subclass's method, then modifying the copied version as necessary. (Of course that has its own problems, since QItemDelegate::drawDisplay() references private member variables that your subclass doesn't have access to, but you can probably work around those. You might also want to check with the Qt people to see if there are any legal problems with copying out a method body like that; I'm not sure if there are or not. If you're not comfortable with copying it, you can at least look at it for inspiration about the sorts of things your implementation of drawDisplay() will probably also need to do)
Essentially, I found that getting the QTableView to display rich text was a common use case that people on forums were trying to accomplish. Since this was a solved problem, I tried to see how I could leverage HTML.
First, I set up my custom delegate to handle rich text. Then I had an algorithm that went a bit like this:
clear all html tags from the display role in every row of the specified column
for every row in the specified column
populate a list of QModelIndex with matching text in the Display Role
for every QModelIndex with matching text in the display role
while there is another occurance of the matching string in the display role
inject html highlight (span) around the matching word
This is, of course, extremely, painfully, unacceptably slow. It does work though, has the exact same effect as hitting ctrl + f. But, I cannot use it. Its a shame that Qt doesn't support something as basic as this. Oh well.
My approach to that problem was to use the paint function from the delegate to render one or several positions from a cursor in a QTextDocument.
void MyDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
if ( !index.isValid() )
return;
// Higlight some text
{
QString dataHighlight QString("col"); // The text to highlight.
QString value = index.model()->data(index, Qt::DisplayRole).toString();
QTextDocument *doc = new QTextDocument(value);
QTextCharFormat selection;
int position = 0;
QTextCursor cur;
// We have to iterate through the QTextDocument to find ALL matching places
do {
cur = doc->find(dataHighlight,position);
cur.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor);
cur.selectionStart();
cur.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor);
cur.selectionEnd();
position = cur.position();
selection.setBackground(Qt::yellow);
cur.setCharFormat(selection);
} while (!cur.isNull());
painter->save();
painter->translate(option.rect.x(), option.rect.y());
doc->drawContents(painter);
painter->restore();
delete doc;
}
}
Is there any QT class for creation text finisher (If I type "hel", it will automatically finished word with "lo")? Sorry for bad terminology, I don't know how to describe it better.
There is QCompleter but that works an QLineEdit and QComboBox by default only. I never used it but I suppose it should be possible to attach it to a customized QTextEdit too.
Maybe google with QCompleter and QTextEdit as keywords.
I have tested adding widgets(QFrame) to a QGridLayout at the same position & it is working fine. Due to the rigidity of code I cannot add a Stacked Widget. So I am adding the Widgets in the same position & making all (except the one I want to display) hide by setVisible(false);
Is this method fine or is my code running by chance & might crash some day?
Thank You.
Qt's help does not forbid you to do this, though this code is strange. I would definitely recomend you to use QStackedLayout, or, at least, QHBoxLayout.
I am not sure whether this is the good method of doing things.
I got an excellent answer to another question here: Remove Widget from QGridLayout in Qt?
So I guess it is better to remove the widget by using the algorithm as mentioned in the answer to above question.