c++ - 将 focusOutEvent 的函数分配给小部件

Question

我想在 lineedit1 失去焦点后做一些具体的事情。这是应用程序的代码片段:

QFocusEvent* focuslost = new QFocusEvent(QEvent::FocusOut);
void lineedit1::focusOutEvent(focuslost) {
  //do something
}

但它给了我编译器错误:

error: name followed by "::" must be a class or namespace name

我该怎么做才能实现这样的功能？

Answer 1

你不能只覆盖一个对象实例的方法，你需要创建一个继承自QLineEdit的新类并覆盖方法focusOutEvent:

mylineedit.h

class MyLineEdit : public QLineEdit
{
protected:
    void focusOutEvent(QFocusEvent * e) override;
}

mylineedit.cpp

void MyLineEdit::focusOutEvent(QFocusEvent * e)
{
    // your code here

    QLineEdit::focusOutEvent(e);
}

然后将lineedit1声明为MyLineEdit* lineedit1