I'm new to qt and exploring it .I want to have a text which is center aligned in my Mainwindow's toolbar.Below is my code inside my MainWindow constructor:
QLabel* label=new QLabel("Hello World");
label->setAlignment(Qt::AlignHCenter);
QHBoxLayout *layout = new QHBoxLayout();
layout->addWidget(label);
QWidget* wid = new QWidget;
wid->setLayout(layout);
ui->mainToolBar->addWidget(wid);
The above code displays the text , but not at the center.It displays at the left.What am I missing?Any help will be really helpful.
label->setAlignment(Qt::AlignHCenter);
This tells the label to (horizontally) center the text in itself.
layout->addWidget(label);
This is expanded by default argument to
layout->addWidget(label, 0);
Where the 0 is the stretch factor of the label within this layout. Zero means your label will be given as much space as it needs to display properly but nothing more. So your label is just as big as your text needs, has it's text centered, but since it's on a QHBoxLayout it's shown on the left side within your bar. If there are no other widgets in your bar's layout, you can set the stretch-factor to 1 to make the label fill the layout, your text will then show in the center.
layout->addWidget(label, 1);
Related
I need a QTextEdit widget which height grows or shrinks to the size of the inner content. I didn't find built-in solution and decided to make my own with connections to &QTextEdit::textChanged signals that will update size of the widget at runtime. In the code snippet I flattened my custom component to raw QTextEdit for simplicity. The problem is that calculation via QFontMetrics is inaccurate, a vertical scrollbar appears with only some pixels to scroll
I want to get rid of any vertical scrollbars in these text widgets.
However, I don't need to get rid of horizontal scrollbars and here is the second problem arises. Seemingly, horizontal scrolls occupy space in the viewport of the text widget and its internal height shrinks by the height of the scrollbar itself
void TestWindow::setupUi(QWidget *parent)
{
QVBoxLayout *v_box0 = new QVBoxLayout(parent);
v_box0->setContentsMargins(0, 0, 0, 0);
QVBoxLayout *v_scroll_layout = new QVBoxLayout();
v_scroll_layout->setContentsMargins(0, 0, 0, 0);
v_scroll_layout->setSpacing(0);
v_scroll_layout->setAlignment(::Qt::AlignTop);
QWidget *scroll_content = new QWidget();
scroll_content->setLayout(v_scroll_layout);
QScrollArea *v_scroll = new QScrollArea();
v_scroll->setWidgetResizable(true);
v_scroll->setWidget(scroll_content);
v_box0->addWidget(v_scroll);
QSize size;
QTextEdit *edit0 = new QTextEdit();
edit0->setLineWrapMode(QTextEdit::NoWrap);
edit0->setText("Hello World 1\n1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11");
edit0->setFont(viewer_font);
size = edit0->fontMetrics().size(0, edit0->document()->toPlainText());
edit0->document()->setDocumentMargin(0);
edit0->setMinimumHeight(size.height());
QTextEdit *edit1 = new QTextEdit();
edit1->setLineWrapMode(QTextEdit::NoWrap);
edit1->setText("New item");
edit1->setFont(viewer_font);
size = edit1->fontMetrics().size(0, edit1->document()->toPlainText());
edit1->document()->setDocumentMargin(0);
edit1->setMinimumHeight(size.height());
v_scroll_layout->addWidget(edit0);
v_scroll_layout->addWidget(edit1);
setFixedHeight(300);
}
What I want to do is to show new QWidget, which is set in QScrollArea.
The Grid Layout is set in Scroll Area and than VBox Layout is added to the Grid one.
Program allows to add dynamically Labels in this VBox Layout.
I want scroll area has fixed size and when area taken by Labels exceeds scroll area's size (heigth), than scrollbar should appear (and no changes in Scroll Area size).
With my code - adding Labels causes increasing heigth of QWidget (window).
Scrollbar can be seen at the beginning but at some point it disappears... like QScrollArea is no more in there...
QWidget* playlistWindow = new QWidget();
playlistWindow->setAcceptDrops(true);
playlistWindow->resize(200, 300);
QScrollArea* scrollArea = new QScrollArea();
scrollArea->setWidget(playlistWindow);
QVBoxLayout* layout = new QVBoxLayout();
QGridLayout* gridLayout = new QGridLayout();
layout->setAlignment(Qt::AlignTop);
scrollArea->setLayout(gridLayout);
gridLayout->addLayout(layout, 0, 0);
scrollArea->setMaximumHeight(300);
scrollArea->show();
Making my way up the Qt learning curve, I've seen many questions about dynamic layouts but the solutions aren't working for me or I don't quite understand them.
Reference questions:: Qt Scroll Area does not add in scroll bars, How can i make widgets overflow to make a scrollbar appear in Qt?
Question:: I want to have a dynamic layout of a set of widgets within a QScrollArea. I've been able to do this manually in Qt Creator and now I am trying to do it through code.
How do I prevent the widgets from stretching/force the area to scroll?
How do I have the added widgets start from the top? I have a vertical spacer in my QVBoxLayout but that pushes everything to the bottom.
Simple test code::
void MainWindow::on_pushButton_clicked()
{
ui->myScroll->setWidgetResizable(true); //making sure this is set
QPushButton *b = new QPushButton(this);
b->setText(QString("Hello Button"));
QHBoxLayout *h = new QHBoxLayout();
h->addWidget(b,0);
ui->myVBoxLayout->addLayout(h,0);
}
Result:: Left side squished (dynamic) – Right side Ok (set up manually)
Qt Creator Setup:: Left side: dynamic – Right side set up manually
Properties::
You can set use setMinimumHeight() on your buttons for preventing squished buttons. The layout can be configured with setContentsMargin() for space between item-border and item-content (QtDesigner has all four directions set to 9 IIRC) and setSpacing() for space between items (QtDesigner uses a default of 6). Also setWidgetResizable(true) allows your scrollarea to resize the view widgeth inside the area (this is where your layout and children are being placed).
This works for me:
In constructor or code set scrollArea->widget() to hold the QVBoxLayout:
v = new QVBoxLayout;
ui->scrollArea->widget()->setLayout(v);
In Button Slot:
void MainWindow::pushButtonPressed()
{
ui->scrollArea->setWidgetResizable(true);
QPushButton *b = new QPushButton(this);
b->setText(QString("Hello Button"));
QHBoxLayout *h = new QHBoxLayout();
h->addWidget(b,0);
v->addLayout(h);
}
I am creating a UI in Qt that has a QDockWidget containing a QPushButton and QLineEdit. Please refer to the attached mock-up. I have created the widget components and successfully got them up and running. However they are not positioned the way I want them to. Both the elements should float to the left making the extra space to the right stretch when the window is resized.
The code-
this->searchField = new QLineEdit; //"this" is a QDockWidget subclassed Object
searchField->setFixedWidth(200);
mainMenu = new Menu();
QHBoxLayout *layout= new QHBoxLayout;
QSpacerItem *filler = new QSpacerItem(1000, 10);
layout->addWidget(mainMenu->getMenuBar());
layout->addWidget(this->searchField);
layout->addSpacerItem(filler);
Any suggestion or help would be awesome!
Thanks for your time :)
http://qt-project.org/doc/qt-4.8/layout.html
http://qt-project.org/doc/qt-4.8/qboxlayout.html#addStretch
void QBoxLayout::addStretch ( int stretch = 0 )
Adds a stretchable space (a QSpacerItem) with zero minimum size and stretch factor stretch to the end of this box layout.
So this is what your new code would look like:
this->searchField = new QLineEdit;
searchField->setFixedWidth(200);
mainMenu = new Menu();
QHBoxLayout *layout= new QHBoxLayout;
layout->addWidget(mainMenu->getMenuBar());
layout->addWidget(this->searchField);
layout->addStretch(); // Added this
Hope that helps.
I want to create a Qt window that contains two layouts, one fixed height that contains a list of buttons at the top and one that fills the remaning space with a layout that centers a widget vertically and horizontally as per the image below.
How should i be laying out my layouts/widgets. Ive tried a few options with nested horizontal and vertical layouts to no avail
Try making the pink box a QWidget with a QHBoxLayout (rather than just making it a layout). The reason is that QLayouts don't provide functionality to make fixed sizes, but QWidgets do.
// first create the four widgets at the top left,
// and use QWidget::setFixedWidth() on each of them.
// then set up the top widget (composed of the four smaller widgets):
QWidget *topWidget = new QWidget;
QHBoxLayout *topWidgetLayout = new QHBoxLayout(topWidget);
topWidgetLayout->addWidget(widget1);
topWidgetLayout->addWidget(widget2);
topWidgetLayout->addWidget(widget3);
topWidgetLayout->addWidget(widget4);
topWidgetLayout->addStretch(1); // add the stretch
topWidget->setFixedHeight(50);
// now put the bottom (centered) widget into its own QHBoxLayout
QHBoxLayout *hLayout = new QHBoxLayout;
hLayout->addStretch(1);
hLayout->addWidget(bottomWidget);
hLayout->addStretch(1);
bottomWidget->setFixedSize(QSize(50, 50));
// now use a QVBoxLayout to lay everything out
QVBoxLayout *mainLayout = new QVBoxLayout;
mainLayout->addWidget(topWidget);
mainLayout->addStretch(1);
mainLayout->addLayout(hLayout);
mainLayout->addStretch(1);
If you really want to have two separate layouts--one for the pink box and one for the blue box--the idea is basically the same except you'd make the blue box into its own QVBoxLayout, and then use:
mainLayout->addWidget(topWidget);
mainLayout->addLayout(bottomLayout);