Qt programming QComboBox - c++

I am using Qt and C++ to add some features to a freeware called: EASYPAINT.
I had to add a more intuitive method in which the users can see the actual width directly from the tool instead of changing numbers. ( just like in the new windows paint , where you can actually see the line thickness and not pixels.)
I am using a QComboBox. My question is (look at the code first), instead of having 20 (penSizeList->addItem), I know we can have addItems.... But what about the icon. for each Item, will I have to search for 20 different line thickness.png and add them? Or is there another method I can use?
And also, how can I get rid of the string in addItem, and only keep an image or icon in the QComboBox.
QComboBox *penSizeList = new QComboBox();
penSizeList->setIconSize(QSize(100,100));
penSizeList->setStatusTip("Pen Size");
QIcon ONEpxIcon(":/media/actions-icons/clear-gray.png");
QIcon THREEpxIcon(":/media/instruments-icons/canvas-lines1.png");
penSizeList->addItem(ONEpxIcon,"1px");
penSizeList->addItem(THREEpxIcon,"2px");
penSizeList->addItem(THREEpxIcon,"3px");
penSizeList->addItem(THREEpxIcon,"4px");
penSizeList->addItem(THREEpxIcon,"5px");
penSizeList->addItem(THREEpxIcon,"6px");
penSizeList->addItem(THREEpxIcon,"7px");
penSizeList->addItem(THREEpxIcon,"8px");
penSizeList->addItem(THREEpxIcon,"9px");
penSizeList->addItem(THREEpxIcon,"10px");
penSizeList->addItem(THREEpxIcon,"11px");
penSizeList->addItem(THREEpxIcon,"12px");
penSizeList->addItem(THREEpxIcon,"13px");
penSizeList->addItem(THREEpxIcon,"14px");
penSizeList->addItem(THREEpxIcon,"15px");
penSizeList->addItem(THREEpxIcon,"16px");
penSizeList->addItem(THREEpxIcon,"17px");
penSizeList->addItem(THREEpxIcon,"18px");
penSizeList->addItem(THREEpxIcon,"19px");
penSizeList->addItem(THREEpxIcon,"20px");
connect(penSizeList,SIGNAL(activated(int)), this, SLOT(penValueChanged(int)));

Try to do this in loop.
penSizeList->addItem(ONEpxIcon,"1px");
for(int i = 2; i < 21 ; i++)
{
penSizeList->addItem(THREEpxIcon,QString("%1px").arg(i));
}
Or if you have different icons for each line:
for(int i = 1; i < 21 ; i++)
{
penSizeList->addItem(QIcon(QString("iconLine%1.png").arg(i)),QString("%1px").arg(i));
}
If you want only icons, set empty string:
penSizeList->addItem(icon,"");
If you want full image then you should set this image as background. For example:
QPixmap pxmap("G:/2/qt.jpg");
QStandardItemModel *md = new QStandardItemModel;
QStandardItem *iii = new QStandardItem;
iii->setBackground(QBrush(Qt::red));
iii->setText("ss");
QStandardItem *iiii = new QStandardItem;
iiii->setBackground(QBrush(pxmap));
iiii->setText("ss");
md->setItem(1,0,iii);
md->setItem(0,0,iiii);
ui->comboBox->setModel(md);

Related

Qt - How to change a QTextEdit's font size with a QComboBox

im trying to change the font size of a QTextEdit by using a QComboBox which is filled in with different values, so for example when I choose a value in the QComboBox it will change the QTextEdits size to the value I have selected. I have values in the QComboBox but I don't know how to change the QTextEdit's value to the value I have selected.
Below is the code I used to fill the QComboBox with values:
for (int i = 0; i < 102; i+=2){
QStringList list = (QStringList()<<QString::number(i));
ui->combobox->addItem(list);
Any help on what to do from here would be appreciated thank you!
QTextEdit* textEdit = new QTextEdit(......);
QComboBox* fontSizeCombo = new QComboBox(....);
for (int i = 1; i < 102; i += 2) {
fontSizeCombo->addItem(QString::number(i));
}
connect(fontSizeCombo, SIGNAL(currentIndexChanged(QString), SLOT(changeFontSize(QString));
void MyClass::changeFontSize(const QString& selected)
{
textEdit->setFontPointSize(selected.toInt());
}
Don't need appending QStringList with each item.
Don't set font size to 0. Excerpt from the Qt docs:
Note that if s is zero or negative, the behavior of this function is
not defined.

QT GridLayout add Stacked QLabel

I am creating an image gallery, i've implemented the reading in of Files and showing them in a resizable scroll-Area. We've decided to add meta-tags / Buttons and i am searching for a convenient way not to change too much but add this little features.
Any suggestion how i can achieve this? Can i add two Qlabels to each other? I tried to stuck two labels in a new layout and push this to the scrollWidgetLayout, but then i have only one Thumbnail.
//Create new ThumbNail-Object
thumbNail = new Thumbnail(ui->scrollArea);
scrollWidgetLayout->addWidget(thumbNail);
In the picture you can see what i have already and what i need (yellow).
You create a widget that acts like a container and put the labels inside it. Set a layout to this widget, I used QVBoxLayout. A better design would be to create a custom widget by subclassing QWidget, but I just used QFrame to make the example quick and simple.
centralWidget()->setLayout(new QVBoxLayout);
QScrollArea *area = new QScrollArea(this);
area->setWidgetResizable(true);
area->setWidget(new QWidget);
QGridLayout *grid = new QGridLayout;
area->widget()->setLayout(grid);
centralWidget()->layout()->addWidget(area);
for(int row = 0; row < 2; row++)
{
for(int column = 0; column < 5; column++)
{
QFrame *container = new QFrame; // this is your widget.. you can also subclass QWidget to make a custom widget.. might be better design
container->setStyleSheet("QFrame{border: 1px solid black;}"); // just to see the shapes better.. you don't need this
container->setLayout(new QVBoxLayout); // a layout for your widget.. again, if you subclass QWidget do this in its constructor
container->layout()->addWidget(new QLabel("TOP")); // the top label.. in your case where you show the icon
container->layout()->addWidget(new QLabel("BOTTOM")); // the bottom label.. in your case where you show the tag
grid->addWidget(container, row, column); // add the widget to the grid
}
}

Spacing between widgets in QHBoxLayout

I'm trying to create a GUI with QtCreator. For this GUI, I need to display several images with different sizes next to each other. These images should be touching each other.
I use a QWidget with a QHBoxLayout, where I add the labels (with different sizes) containing the images.
According to related questions, I should use setSpacing and setContentsMargin to remove these spaces, but that won't work; I tried several times.
Here's the code:
QWidget *widget = new QWidget(ui->tagcloud);
QHBoxLayout * l = new QHBoxLayout(widget);
ui->tagcloud->setWidget(widget);
for(int i=0;i<list.size();++i)
{
QLabel *lab = new QLabel;
QPixmap pic((list[i].imgPath).c_str()); //This fetches the image
int sizeChange = 50 + (2*list[i].percent); //Calculates the size of the image
lab->setFixedSize(QSize(sizeChange, sizeChange));
lab->setPixmap(pic);
lab->setScaledContents(true);
l->addWidget(lab);
l->setSpacing(0);
}
However, when I run this, the spacing remains the same (i.e. definitely not zero).
If I add more labels to the layout, the spacing seems to get smaller.
Can anyone explain or help me? Thanks!
Setting spacing to 0 and adding stretch before and after works for me :
l->addStretch();
for(int i = 0; i < list.size(); ++i)
{
QLabel *lab = new QLabel;
QPixmap pic((list[i].imgPath).c_str()); //This fetches the image
int sizeChange = 50 + (2*list[i].percent); //Calculates the size of the image
lab->setFixedSize(QSize(sizeChange, sizeChange));
lab->setPixmap(pic);
lab->setScaledContents(true);
l->addWidget(lab);
}
l->addStretch();
l->setSpacing(0);
Also this works I think
l->setSizeConstraint(QLayout::SetMaximumSize);

Qt Scroll Area does not add in scroll bars

Hi guys I have to dynamically create push buttons depending on user inputs, therefore if user gives a large input number the widget containing the push buttons has to have the ability to scroll up and down. For this reason I am using QScrollArea. I generate the template in Qt designer and the UIC generates the code for me after which I add in my part which should handle dynamic creation of push buttons. However, I can not seem to get the vertical scroll bars to appear. Here is the relevant part of the code.
verticalWidget = new QWidget(FWHMWorkflowDialog);
verticalWidget->setObjectName(QString::fromUtf8("verticalWidget"));
verticalWidget->setMinimumSize(QSize(150, 0));
verticalWidget->setMaximumSize(QSize(150, 16777215));
verticalLayout_5 = new QVBoxLayout(verticalWidget);
verticalLayout_5->setObjectName(QString::fromUtf8("verticalLayout_5"));
scrollArea = new QScrollArea(verticalWidget);
scrollArea->setObjectName(QString::fromUtf8("scrollArea"));
scrollArea->setMaximumSize(QSize(150, 16777215));
scrollArea->setWidgetResizable(true);
scrollAreaWidgetContents = new QWidget();
scrollAreaWidgetContents->setObjectName(QString::fromUtf8("scrollAreaWidgetContents"));
scrollAreaWidgetContents->setGeometry(QRect(0, 0, 130, 432));
numberOfSlices = numberSlices;
for (int i = 0; i < numberOfSlices; i++)
{
QWidget *horizontalWidget = new QWidget(scrollAreaWidgetContents);
horizontalWidget->setMaximumSize(150,40);
horizontalWidget->setGeometry(QRect(0, i*40, 150, 40));
hWidgetList.push_back(horizontalWidget);
QHBoxLayout *hLayout = new QHBoxLayout(horizontalWidget);
hLayoutList.push_back(hLayout);
hLayout->setSizeConstraint(QLayout::SetMinimumSize);
hLayout->setContentsMargins(-1, 1, -1, 1);
QPushButton *pushButton = new QPushButton(horizontalWidget);
pushButtonList.push_back(pushButton);
QString temp = QString("m_sliceButton").arg(i);
pushButtonList[i]->setObjectName(temp);
pushButtonList[i]->setGeometry(QRect(10, 20+i*40, 98, 27));
hLayout->addWidget(pushButton);
QCheckBox *checkBox = new QCheckBox(horizontalWidget);
checkBoxList.push_back(checkBox);
temp = QString("m_checkBox").arg(i);
checkBoxList[i]->setObjectName(temp);
checkBoxList[i]->setEnabled(true);
checkBoxList[i]->setGeometry(QRect(110, 20+i*40, 21, 22));
hLayout->addWidget(checkBox);
}
scrollArea->setWidget(scrollAreaWidgetContents);
//scrollArea->setWidgetResizable(true);
verticalLayout_5->addWidget(scrollArea);
The output window always looks like the following.
In this example the input by the user is 25 however you can see that the 21st button is cut off and 4 other buttons are not visible.
The size window problem occurring after scroll functionality started working.
You need to add your horizontalWidget to a vertical widget like so:
QVBoxLayout* vLayout = new QVBoxLayout();
for (int i = 0; i < numberOfSlices; i++)
{
QWidget *horizontalWidget = new QWidget();
vLayout->addWidget(horizontalWidget);
....
}
scrollAreaWidgetContents->setLayout(vLayout);
You second problem looks like it comes from this line:
scrollArea = new QScrollArea(verticalWidget);
You're adding scrollArea directly to verticalWidget, but to get it to lay out the way you want you need to put it in a layout. Try the following instead:
QVBoxLayout* l = new QVBoxLayout();
l->addWidget(sliceLabel); // or whatever you call it
l->addWidget(scrollArea);
l->addWidget(clearButton); // again, your name here
verticalWidget->setLayout(l);
Try playing around with the QScrollBarPolicy.
http://doc.qt.digia.com/qt/qabstractscrollarea.html#horizontalScrollBarPolicy-prop
I'm guessing that the default behavior isn't working because there is something strange going on with layouts.

QScrollArea with multiple QWidgets only shows empty box

I am trying to create a widget that would display some information. Each information would be a QWidget that contains multiple QLabel with text (the information). My idea is to put multiple (array of these) into a QScrollArea so that the user can view them scrolling up and down. The following code:
InfoWidget::InfoWidget(QWidget* parent) : QWidget(parent){
widgets = new QVector<MarkerInfoWidget*>();
csv_data = 0;
csv_velocity = 0;
labels = 0;
infoWidgetLayout = new QVBoxLayout(this);
setLayout(infoWidgetLayout);
scrollArea = new QScrollArea(this);
scrollWidgetLayout = new QVBoxLayout(scrollArea);
scrollArea->setLayout(scrollWidgetLayout);
infoWidgetLayout->addWidget(scrollArea);
//Test
QString name = "TEST";
for(int i=0; i<10; i++){
MarkerInfoWidget* markerWidget = new MarkerInfoWidget(name, scrollArea);
scrollWidgetLayout->addWidget(markerWidget);
widgets->append(markerWidget);
}
}
Both MarkerInfoWidget and InfoWidget extends QWidget. What I am getting is simply a box that has very small text:
If I drag it out and re-size it, it display correctly:
What I have noticed is that if I re-size it too small, it does not generate scrolls. What do I need to fix this?
I guess changing:
scrollArea->setLayout(scrollWidgetLayout);
to sth like:
QFrame* frame = new QFrame(scrollArea);
frame->setLayout(scrollWidgetLayout);
scrollArea->setWidget(frame);
As far as i know you have to put widget into QScrollableArea to make it really scrollable. Setting its layout is probably not the thing you want to do.