Qt 设置 QWidget 的默认宽度

Question

One of those days when you get stuck on something stupid. I've got the Min/Max width set, but it defaults to the Max width. I want it to default to the minimum width. How do I do this.

Answer 1

I also had massive trouble understanding why there isn't a "set to this size, but don't fix the values" method. It's called resize, like this:

QWidget *widget= new QWidget();
label->resize(50,50);

Answer 2

Consider the following code

QLabel *label = new QLabel();
label->setMinimumSize(50,50);
label->setMaximumSize(100,100);
label->setText("Hello World");
label->show();

Here label will be displayed with the size 50:50(width:height) and we can enlarge it to maximum 100:100(width:height). Here MinumumSize is given as 50:50 and MaximumSize is given as 100:100.

Answer 3

You can set the default minimum width/height like this:

int width = 100;
int height = 100;
QWidget * widget = new QWidget();
widget->setMinimumSize(width, height);
widget->deleteLater();

See more about setMinimumSize here: http://qt-project.org/doc/qt-4.8/qwidget.html#minimumSize-prop

Answer 4

Is your widget in a layout ? You can try to change the size policy:

widget->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);

Answer 5

Getting the default size of a widget can be done using:

QWidget widget(this);
widget.minimumSizeHint()

it returns the minimum size, the widget wants to have to be able to display the content.

Eg:

QSpinBox aSpinBox(this);
const QSize defaultSizeSpinBox = aSpinBox.minimumSizeHint();
std::cout << defaultSizeSpinBox.width() << std::endl;