我有一个QSpinbox
我要设置的范围:
QSpinBox *SpinBox = new QSpinBox;
SpinBox->setRange(0, 100);
但是,我可以手动输入一个+
符号,该符号不会反映在我的广告位中。
connect (SpinBox, SIGNAL (valueChanged (QString)), this,
SLOT (onSpinBoxChanged (QString)));
我也尝试用QString
替换int
。但是+
不会反映在广告位中。
如何限制输入+
符号?
我已经提到了一些Qt和StackOverflow帖子/答案,它们禁用了Spinbox中的行编辑:
我试图对Spinbox进行行编辑ReadOnly
,但由于它是const
变量,所以我无法这样做。
一些答案建议继承QSpinbox
类。
是否有其他方法来限制+
符号或禁用QSpinbox
的行编辑本身?
答案 0 :(得分:3)
如果不想从QSpinBox
类继承,可能的解决方案是使用eventFilter
,在下面的代码中,我显示一个示例:
#include <QApplication>
#include <QSpinBox>
#include <QLineEdit>
#include <QKeyEvent>
class PlusRemoveHelper: public QObject{
public:
using QObject::QObject;
void addWidget(QWidget *widget){
if(widget){
widgets.append(widget);
widget->installEventFilter(this);
}
}
public:
bool eventFilter(QObject *watched, QEvent *event) override
{
if(std::find(widgets.begin(), widgets.end(), watched) != widgets.end()
&& event->type() == QEvent::KeyPress){
QKeyEvent *keyevent = static_cast<QKeyEvent *>(event);
if(keyevent->text() == "+")
return true;
}
return QObject::eventFilter(watched, event);
}
private:
QWidgetList widgets;
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QSpinBox w;
w.setRange(0, 100);
PlusRemoveHelper helper;
helper.addWidget(&w);
w.show();
return a.exec();
}
如果您位于小部件内,则可以实现相同的逻辑:
*。h
...
class QSpinBox;
class SomeClass: public SuperClass
{
...
public:
bool eventFilter(QObject *watched, QEvent *event);
private:
...
QSpinBox *SpinBox
};
*。cpp
SomeClass::SomeClass(...):
SuperClass(..)
{
SpinBox = new QSpinBox;
SpinBox->setRange(0, 100);
SpinBox->installEventFilter(this):
}
bool SomeClass::eventFilter(QObject *watched, QEvent *event){
if(watched == SpinBox && event->type() == QEvent::KeyPress){
QKeyEvent *keyevent = static_cast<QKeyEvent *>(event);
if(keyevent->text() == "+")
return true;
}
return SomeClass::eventFilter(watched, event);
}