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对于我的 GUI，我希望有两对按钮可以在滚动区域中上下滚动。第一组按钮应该在滚动区域 1 上工作，第二组按钮应该在滚动区域 2 上工作。我放在滚动区域中的小部件称为 viewport1 和 viewport2。 由于两组按钮都应该执行相同的操作（向上和向下滚动），我想我会创建两个名为scrollUp和scrollDown的插槽来处理两组按钮的滚动。不幸的是我无法完成这项工作并且需要一些帮助。我已经尝试过以下方法：

QPushButton up;
QPushButton down;
QPushButton up2;
QPushButton down2;

connect(&up,SIGNAL(clicked()),&up,SLOT(scrollUp()));
connect(&up2,SIGNAL(clicked()),&up,SLOT(scrollUp()));
connect(&down,SIGNAL(clicked()),&down,SLOT(scrollDown()));
connect(&down2,SIGNAL(clicked()),&down,SLOT(scrollDown()));

void MainWindow::scrollDown()
{
QScrollArea area;
QWidget view;

if((QPushButton) &sender = down)
{
    area=scrollArea;
    view=viewport;
}
if((QPushButton) &sender = down2)
{
    area=scrollArea;
    view=viewport;
}
int curpos = area.verticalScrollBar()->value();
area.verticalScrollBar()->setValue(curpos+15);
int newpos = area.verticalScrollBar()->value();
QPoint topLeft = area.viewport()->rect().topLeft();
view.move(topLeft.x(),topLeft.y()-(newpos));
}

void MainWindow::scrollUp()
{
QScrollArea area;
QWidget view;

if((QPushButton) &sender = up)
{
    area=scrollArea;
    view=viewport;
}
if((QPushButton) &sender = up2)
{
    area=scrollArea2;
    view=viewport2;
}
int curpos = area.verticalScrollBar()->value();
area.verticalScrollBar()->setValue(curpos-15);
int newpos = area.verticalScrollBar()->value();
QPoint topLeft = area.viewport()->rect().topLeft();
view.move(topLeft.x(),topLeft.y()-(newpos));
}

但由于多种原因，这不起作用。我还尝试给插槽一些参数，例如：

connect(&up,SIGNAL(clicked()),&up,SLOT(scrollUp(scrollarea1,viewport1)));
connect(&up2,SIGNAL(clicked()),&up,SLOT(scrollUp(scrollarea2,viewport2)));

但再次没有成功。有谁能够帮助我？

首先，“它不起作用”并不意味着什么，如果你不说出你遇到了什么错误，就很难帮助你。那么，问题就很少了。

所有QObject派生类都是不可复制的，这意味着你不能这样做

QWidget a;
QWidget b;
b = a; // Wrong

您应该使用指针（或者也许是引用）。

QWidget a;
QWidget * b = new QWidget(...);
QWidget * c;
c = & a; // Ok
c = b; // Ok

那么你的connect调用错误：

connect(&up, SIGNAL(clicked()), &up, SLOT(scrollUp()));

第三个参数是拥有槽的对象。up是一个 QPushButton，它没有scrollUp()插槽，是您的主窗口执行以下操作：

connect(&up, SIGNAL(clicked()), this, SLOT(scrollUp()));

(since connect在 MainWindow 的构造函数中调用this指向当前的 MainWindow 对象）。

同样在 C++ 中=符号表示赋值，用于相等比较使用=='. Andsender` 是一个函数。

如果以正确的方式实施，您的方法应该有效：

class MainWindow: public QWidget
{
    QScrollArea * scroll1;
    QScrollArea * scroll2;
    QWidget * view1;
    QWidget * view2;
    QPushButton * up1;
    QPushButton * up2;
    QPushButton * down1;
    QPushButton * down2;

public:
    MainWindow()
    {
        // Here initialize member variables.
        ...

        connect(up1, SIGNAL(clicked()), this, SLOT(scrollUp()));
        connect(up2, SIGNAL(clicked()), this, SLOT(scrollUp()));
        connect(down1, SIGNAL(clicked()), this, SLOT(scrollDown()));
        connect(down2, SIGNAL(clicked()), this, SLOT(scrollDown()));
    }

public slots:
    void scrollDown()
    {
        QScrollArea * area;
        QWidget * view;

        if(qobject_cast<QPushButton>(sender()) == down1) {
            area = & scroll1;
            view = & view1;
        } else if(qobject_cast<QPushButton>(sender()) == down2) {
            area = & scroll2;
            view = & view2;
        } else {
            // Error.
        }

        // Now `area` and `view` point to the right widgets.
        ...
    }

    void scrollUp()
    {
        // The same as before.
    }
};

另一种方法是将实际的滚动指令提取到单独的函数中：

class MainWindow: public QWidget
{
    // Same variables as before
    ...

public:
    MainWindow()
    {
        // Here initialize member variables.
        ...

        connect(up1, SIGNAL(clicked()), this, SLOT(scrollUp1()));
        connect(up2, SIGNAL(clicked()), this, SLOT(scrollUp2()));
        connect(down1, SIGNAL(clicked()), this, SLOT(scrollDown1()));
        connect(down2, SIGNAL(clicked()), this, SLOT(scrollDown2()));
    }

public slots:
    void scrollDown(QScrollArea * area, QWidget * view)
    {
        // Here you scroll over `area` and `view`.
    }

    void scrollDown1()
    {
        scrollDown(scroll1, area1);
    }

    void scrollDown2()
    {
        scrollDown(scroll2, area2);
    }

    // Again, the same for `scrollUp`.
};