I want to have the following layout in a Qt-C++ project: A VBoxLayout with in it two QTextEdits underneath each other. The top one should shrink to have the minimal size: 1 line of text if there's one line in it, bigger if there's more. The bottom one should take the remaining space in the window.
I now have the following code in the constructor of my mainwindow (which extends QMainWindow):
QWidget *mainpanewidget = new QWidget(this);
QVBoxLayout *mainpane = new QVBoxLayout(mainpanewidget);
this->setCentralWidget(mainpanewidget);
QTextEdit *firsttext = new QTextEdit(this);
firsttext->setText("first text");
QTextEdit *secondtext = new QTextEdit(this);
secondtext->setText("second text");
//first try: use sizepolicies
firsttext->setSizePolicy(QSizePolicy::Minimum,QSizePolicy::Minimum);
secondtext->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
//second try: explicitely set minimum size to something small
firsttext->setMinimumHeight(10);
firsttext->setMinimumWidth(10);
//3th try: stretch factors
mainpane->setStretchFactor(firsttext,0);
mainpane->setStretchFactor(secondtext,1);
//4th try: size policy of surrounding layout
mainpanewidget->setSizePolicy(QSizePolicy::Minimum,QSizePolicy::Minimum);
mainpane->addWidget(firsttext);
mainpane->addWidget(secondtext);
mainpane->update();
With this code the second QTextEdit does become larger than the first one, but the first one seems to think it's minimal size should be 192 pixels (14 lines), which is far above it's real necessary number of lines: 1. This is the size given by sizehint, instead of minimalheight. Unfortunately there doesn't seem to be a way to adapt sizehint without subclassing QTextEdit.
I have tried different things, as can be seen in the above code, to come up with one minimal QTextEdit and one expanding. The only one that works is to set the maximumheight of the first QTextEdit, which is something I don't want to hardcode as the text in it may be larger than some limit I hardcode now. Plus hardcoding limits is not very good coding practice.
As I want to use similar sizing for different qwidgets in my application (QTextEdit, labels, buttons,...) I would prefer to not have to use inheritance, as this would bring in a lot of extra classes which all change but a single thing of their parent class.
I work in Qt 5.7.0.
Note: there seem to be a lot of questions regarding qsizepolicy and resizing in Qt. If I missed a duplicate of this question you are free to link it and close this one.
Related
I'm grouping a set of widgets in a parent and then I control the visibility/flow of these widgets by hiding/showing the parent. Is this a good way to achieve what I'm trying to do? Here is the code:
QVBoxLayout* l = new QVBoxLayout(this);
// .....
QWidget* toolset_frame = new QWidget(this);
{
QVBoxLayout* l = new QVBoxLayout(toolset_frame);
l->addWidget(new QLabel(tr("Stuff")));
this->Toolset = new QLineEdit(toolset_frame);
l->addWidget(this->Toolset);
}
l->addWidget(toolset_frame);
// Call toolset_frame->hide() and this hides everything inside the parent
The problem with this solution is that the children shrink in size slightly, I think this is due to some padding or border in the parent. Ideally the children should appear as if they are not contained in an intermediate object, but rather flow with the parent. In this case the horizontal size of the children should not be affected.
http://doc.qt.io/qt-5/qtwidgets-dialogs-extension-example.html
This example shows that your approach is correct. Using a widget to contain the elements you want to hide, and so on.
If you want the margins/content margins/padding to be less, then change it.
// in finddialog.cpp
extensionLayout->setMargin(0);
To quickly prototype what properties to change to get it to look right, try laying it out in the Qt Designer, and modify the property editor to get the look and feel you want.
Hope that helps.
Using a QTextEdit, I need to change the font attributes of each paragraph individually. This is similar to how many word processors change the font of a paragraph when the user select a style from a menu (not a specific formatting).
Ideally, I would like to apply a QTextCharFormat (or equivalent) to a block (paragraph) just before it is laid out and rendered, but I would prefer that no font attribute be actually inserted in the text, as I don't want this information in the file but I need to preserve any bold/italic/underline attributes that the user might have set to words within paragraphs (I intend to save the needed information in a QTextBlock::userData). However, I can't figure where I would need to insert a function to perform this task.
I figured I could not change the QTextCharFormat of a paragraph from either QTextBlock nor QTextCursor as this only applies to new blocks, it doesn't affect blocks with existing text.
I checked out QTextLayout but I don't think my answer is there.
I have been looking for a solution to this problem for a few days now. I would be really gracious for any pointer in the right direction.
I have years of experience with C++, but I'm somewhat new to Qt. Using Qt 4.8.
Edit:
I added emphasize (bold) above to an important part of what I'm trying to do. In other word, what I'd really like to do is be able to apply the font attributes to the block of text (perhaps a temporary copy) just before it is displayed. I'm totally comfortable with deriving and modifying (even reimplement) any class that I need to in order to achieve that goal, but I need to be pointed to the right direction as to what I actually need to change. As a last resort, I could also modify some Qt class directly if that is necessary for the task, but again would need to know what class I need to touch. I hope this is clearer. I find it difficult to explain this without being allowed to tell you what the application will do exactly.
[Required Libraries]
#include <QTextEdit> // not needed if using the designer
#include <QTextDocument>
#include <QTextBlock>
#include <QTextCursor>
[Strategy]
QTextDocument
I need it to manage the blocks. The function QTextDocument::findBlockByNumber is quite handy to locate the previous blocks, and I think it is what you are after.
QTextBlock
Container for block texts. A nice and handy class.
QTextCursor
Surprisingly, there is no format-setter in QTextBlock class. Therefore I use QTextCursor as a workaround since there are four format-setters in this class.
[Code for formatting]
// For block management
QTextDocument *doc = new QTextDocument(this);
ui->textEdit->setDocument(doc); // from QTextEdit created by the Designer
//-------------------------------------------------
// Locate the 1st block
QTextBlock block = doc->findBlockByNumber(0);
// Initiate a copy of cursor on the block
// Notice: it won't change any cursor behavior of the text editor, since it
// just another copy of cursor, and it's "invisible" from the editor.
QTextCursor cursor(block);
// Set background color
QTextBlockFormat blockFormat = cursor.blockFormat();
blockFormat.setBackground(QColor(Qt::yellow));
cursor.setBlockFormat(blockFormat);
// Set font
for (QTextBlock::iterator it = cursor.block().begin(); !(it.atEnd()); ++it)
{
QTextCharFormat charFormat = it.fragment().charFormat();
charFormat.setFont(QFont("Times", 15, QFont::Bold));
QTextCursor tempCursor = cursor;
tempCursor.setPosition(it.fragment().position());
tempCursor.setPosition(it.fragment().position() + it.fragment().length(), QTextCursor::KeepAnchor);
tempCursor.setCharFormat(charFormat);
}
Reference:
How to change current line format in QTextEdit without selection?
[DEMO]
Building Environment: Qt 4.8 + MSVC2010 compiler + Windows 7 32 bit
The demo is just for showing the concept of setting the format on a specific block.
Plain text input
Format 1 (notice that it won't bother the current cursor in view)
Format 2
You can use QTextCursor to modify existing blocks.
Just get a cursor and move it to the beginning of the block. Then move it with anchor to create a selection.
Set this cursor to be the current cursor for the text edit and apply your changes.
QTextEdit accepts HTML so all you have to do is to format your paragraphs as HTML. See example below:
QString text = "<p><b>Paragraph 1</b></p><p><i>Paragraph 2</i></p>";
QTextCursor cursor = ui->textEdit->textCursor();
cursor.insertHtml(text);
That will create something like this:
Paragraph 1
Paragraph 2
Having said that, there is only a subset of HTML that is supported in Qt. See Supported HTML Subset
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.
I'm working on my first QT application and I have a problem with QListWidgetItems.
I will be having different kind of list.
for checkboxed list using:
listElement[i]->setFlags(Qt::ItemIsEnabled);
listElement[i]->setCheckState(Qt::Unchecked);
works exactly as wanted.
But now I want a Radio Button list. so my question is in two parts
can use the same logic that I used for checkBox to create Radio Buttons?
I have used:
listElement[i]->setFlags(Qt::ItemIsEnabled);
QRadioButton *radio1 = new QRadioButton(0);
dlList->setItemWidget(listElement[i],radio1);
this will display Items in the list with a radio Button, the problem is that the text is Over the Radio Button:
going to try to demonstrate without image
This is a test
o
for elements 1
instead for checkbox I have
This is a test
[]
for element 1
how can I get the radioButton to align correctly with text?
New Questions:
Thanks alot for the answers my text is next to my RadioButton now.
Only thing there is no WordWrap, My text is Longer than maximum Size of the RadioButton. How can I get it to wordwrap:
rButton = new QRadioButton();
rButton->setFixedSize(LIST_TEXT_WIDTH_WO_ICON, LIST_TEXT_HEIGHT);
rButton->setStyleSheet("border:none");
rButton->setFont(segoe18Font);
rButton->setText("This is just a test for elementsss of type euh!!!");
rButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);
dropListWidget->setItemWidget(listElement, rButton);
As you may have read, there are two approaches to achieve what you want.
The most flexible one: use a QListView, implement a new delegate and a model if necessary.
Keep using the classic item-based interface (QListWidget) and change the item's widgets either by sub-classing QListWidgetItem or calling QListWidgetItem::setItemWidget.
Since the question points towards the second one, I'll try to provide the simplest item-based solution.
The following piece of code generates the list widget in the picture.
QListWidgetItem *it;
it = new QListWidgetItem(ui->listWidget);
ui->listWidget->setItemWidget(it, new QRadioButton(tr("Item 1")));
it = new QListWidgetItem(ui->listWidget);
ui->listWidget->setItemWidget(it, new QRadioButton(tr("Item 2")));
// .
// .
// .
it = new QListWidgetItem(ui->listWidget);
ui->listWidget->setItemWidget(it, new QRadioButton(tr("Item N")));
where ui->listWidget is a pointer to the QListWidget that holds the items.
I hope this helps. As far as I understand, that's what you need.
I would like to ask if anyone knows how to display 2 QToolBars in two lines, one on top of the other? I found the class QStyleOptionToolBar, but I don't know how to use it...
It is easy to drag one toolbar with the mouse to be placed below the other, so I think there must be a way how this can be done from the source code as well...
Any hint would be appreciated!
Claus
Try calling QMainWindow::addToolBarBreak(Qt::ToolBarArea) in between adding the two tool bars.
I think that when you add the 2 toolbar's if you place them in the same area, they'll stack automatically:
QMainWindow *mainWin = get_main(); // however you get it
mainWin->addToolBar(Qt::TopToolBarArea, new QToolBar);
mainWin->addToolBar(Qt::TopToolBarArea, new QToolBar);
This should produce 2 toolbars, both at the top.
If you want toolbars to be in two lines you should do it in following manner:
firstToolbar = new QToolBar(this);
secondToolbar = new QToolBar(this);
addToolBar(Qt::TopToolBarArea, firstToolbar);
addToolBarBreak();
addToolBar(Qt::TopToolBarArea, secondToolbar);
addToolBarBreak accepts Qt::ToolBarArea so you can specify for which area you would like to add the break. By default it is Qt::TopToolBarArea.