QLineEdit - 焦点事件 [英] QLineEdit - focus event
问题描述
我必须将焦点事件从一些QLineEdit元素( ui-> lineEdit )连接到方法 focus()。我如何做到这一点?
I have to connect focus event from some QLineEdit element (ui->lineEdit) to the method focus(). How can I do this?
推荐答案
当QLineEdit获得焦点时没有信号发射。因此,将方法连接到焦点事件的概念不是直接合适的。
There is no signal emitted when a QLineEdit gets the focus. So the notion of connecting a method to the focus event is not directly appropriate.
如果你想有一个聚焦
信号,你将得到QLineEdit类。
If you want to have a focused
signal, you will have to derive the QLineEdit class. Here is a sample of how this can be achieved.
在 myLineEdit.h
文件中,您有:
class MyLineEdit : public QLineEdit
{
Q_OBJECT
public:
MyLineEdit(QWidget *parent = 0);
~MyLineEdit();
signals:
void focussed(bool hasFocus);
protected:
virtual void focusInEvent(QFocusEvent *e);
virtual void focusOutEvent(QFocusEvent *e);
}
在 myLineEdit.cpp
file你有:
MyLineEdit::MyLineEdit(QWidget *parent)
: QLineEdit(parent)
{}
MyLineEdit::~MyLineEdit()
{}
void MyLineEdit::focusInEvent(QFocusEvent *e)
{
QLineEdit::focusInEvent(e);
emit(focussed(true));
}
void MyLineEdit::focusOutEvent(QFocusEvent *e)
{
QLineEdit::focusOutEvent(e);
emit(focussed(false));
}
现在可以连接 MyLineEdit :: focused )
发送到您的 focus()
方法(插槽)。
You can now connect the MyLine:focussed()
signal to your focus()
method (slot).
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