c++ - 如何更改 qlist 中颜色的值

Question

我有一个圆形对象，它包含绘制它的属性，如宽度、坐标 xy、颜色。我有一个这个圆圈（对象）的 qlist，但是当我尝试更改颜色时出现错误。

class Circle {
 int x;
 int y;
 int width;
 QColor color
}

QList <Circle> circles;

我在列表中添加了一些圈子，这是问题所在

circles.at(3).color = Qt::yellow;

将 'const QColor' 作为 'QColor& QColor::operator=(Qt::GlobalColor)' 的 'this' 参数传递会丢弃限定符 [-fpermissive]

Answer 1

The at() function of a QList returns a const reference: const T & QList::at(int i) const, so you can not modify it. Use operator[] instead: circles[3].color = Qt::yellow

Also note that right now all members of your class are private (by default), so you will not be able to set color anyway.