c++ - QLayout 对齐小部件错误

Question

我有QLayout接受 QLabel 的类(class)并将其对齐为 Qt::AlignRight在单元格中，最初我认为它正在工作(因为布局单元格的大小正好等于像素图的大小)，我有一个与 QLabel 关联的事件，即当mousepressEvent发生了 QLabel 的大小增加(单元格的大小也增加，因此整个列的大小增加)，那一次另一个QLabel在 QLayout正在左对齐，我希望它们右对齐或居中对齐而不是左对齐，

我的代码是，

Container::Container()
{ 
    Layout = new QGridLayout;
    Layout->setHorizontalSpacing(0);
    Layout->setVerticalSpacing(10);
    Layout->setMargin(10); 
    for(int i = 0; i < 4; ++i)
    {
        holes[i] = new Hole; 
        Layout->addWidget(ui_holes[i], i, 0, 1, Qt::AlignRight);
        ui_holes[i].setPixmap("mypixmapname.png")
    } 
    Layout->setAlignment(Qt::AlignCenter);
    setLayout(Layout); 
    setMaximumSize(200,760);
    setMinimumSize(200,760);
    setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed);
}

void Screen::mousePressEvent(QMouseEvent *tevent)
{ 
    if(childAt(tevent->pos()))
    { 
        if(childAt(tevent->pos())->objectName() == "Hole")
        { 
            hole = static_cast<Hole *>(childAt(tevent->pos()));  
            hole->resize(QSize(160,160));  
        }
    }  
}  

void Screen::mouseReleaseEvent(QMouseEvent*)
{ 
    if(hole)
    {
        ui_Hole->resetSize();  
    } 
}

Hole 是继承自 QLabel 的类，我为 Hole 创建了两个新的成员函数是 resetSize 和 resize，

void Hole::resize(QSize size)
{
    setSize(size);
    if(!ui_HoleFlags[PIXMAP_EXISTS])
        return  void(0);
    QPixmap *tempPixmap = ui_resourceIcon();
    setPixmap(tempPixmap->scaled(size,Qt::IgnoreAspectRatio));
    delete tempPixmap;
} 

QPixmap* Hole::ui_resourceIcon()
{
    if(!ui_HoleFlags[ICON_EXISTS])
        return NULL;
    QPixmap *tempPixmap = new QPixmap(*pixmap());
    return tempPixmap;
}

void Hole::setSize(QSize size)
{
    setMaximumSize(size);
    setMinimumSize(size);
}

void Hole::resetSize()
{
    if(ui_HoleFlags[PIXMAP_EXISTS])
        setPixmap(*Pixmap);
    setSize(ICON_SIZE);
}

提前致谢

Answer 1

通过这种方式，无论单个标签的大小如何，您都可以使标签始终居中对齐。

#include <QLabel>
#include <QApplication>
#include <QLayout>
#include <QMouseEvent>

class Window : public QWidget
{
public:
    Window(QWidget *parent = 0) {}
    virtual ~Window() {}

protected:
    void mousePressEvent(QMouseEvent *event)
    {
        if (childAt(event->pos())) {
            QLabel *label = dynamic_cast<QLabel *>(childAt(event->pos()));
            if (label) {
                label->setMinimumSize(QSize(50, 50));
                label->setMaximumSize(QSize(50, 50));
            }
        }
    }
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    Window *window = new Window;
    window->show();
    window->resize(400, 300);

    QVBoxLayout *vLayout = new QVBoxLayout;

    QLabel *labels[4];
    for(int i = 0; i < 4; ++i) {
        labels[i] = new QLabel();
        labels[i]->setMaximumSize(30, 30);
        labels[i]->setMinimumSize(30, 30);

        QHBoxLayout *hLayout = new QHBoxLayout;
        hLayout->addItem(new QSpacerItem(10, 10, QSizePolicy::Expanding, QSizePolicy::Minimum));
        hLayout->addWidget(labels[i]);
        hLayout->addItem(new QSpacerItem(10, 10, QSizePolicy::Expanding, QSizePolicy::Minimum));
        vLayout->addLayout(hLayout);
    }

    window->setLayout(vLayout);
    window->setStyleSheet("QLabel {border: 1px solid red;}");

    return app.exec();
}