Qt - 创建QPainter

Question

我正在尝试paintEvent在我的程序中重写方法并更改它.

void MainWindow::paintEvent(QPaintEvent *event)
{
    QRegion reg = this->bgPixmapHandle->rect();
    QPainter painter(this);

    painter.setClipRegion(reg);
    painter.drawImage(bgPixmapHandle->rect(), bgPixmapHandle);
    painter.end();
}

在这里,我尝试改变我的bg形象.但我在网上收到了错误:QPainter painter(this);

错误:变量'QPainter painter'已初始化,但类型不完整

Answer 1

包含QPainter头文件.QPainter类仅在您在该翻译单元中包含的Qt标头之一中进行前向声明.