Question

我有一个包含我的自定义小部件的QScrollArea。当我更改自定义窗口小部件的数据（更改sizeHint（）并且窗口小部件占用更多空间）时，每行的结尾和最后几行都被截断。我创建了一个小程序来复制这个问题。

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QString>

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);

    void changeData(const QString &, const unsigned &, const unsigned &);

    QSize sizeHint() const override;
protected:
    void paintEvent(QPaintEvent *event) override;

private:
    QString lines;
    unsigned lineSize = 0, rowSize = 0;
};

#endif // WIDGET_H

的main.cpp

#include "widget.h"
#include <QApplication>
#include <QtWidgets>

Widget::Widget(QWidget *parent) : QWidget(parent)
{
    changeData("TESTING\nFUNCTIO\n1234567\nWORDS77\n", 7, 4);
    update();
}

void Widget::changeData(const QString &l, const unsigned &lineSz, const unsigned &rowSz)
{
    lines = l;
    lineSize = lineSz;
    rowSize = rowSz;
}

void Widget::paintEvent(QPaintEvent * /*event*/)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);

    QFont defaultFont = painter.font();
    QPen defaultPen = painter.pen();
    defaultFont.setLetterSpacing(QFont::AbsoluteSpacing, lineSize / 2 - 3);
    // set pen and font
    painter.setFont(defaultFont);
    painter.setPen(defaultPen);
    // starting point
    QPoint prntPoint(5, 15);

    for (QString::size_type ind = 0, row = 1; ind < lines.size(); ++ind)
    {
        if (lines[ind] != '\n') // if it's a letter
        {
            // print the letter and move the point to the right
            painter.drawText(prntPoint, QString(lines[ind]));
            prntPoint.setX(prntPoint.x() + 20);
        }
        else if (lines[ind] == '\n') // if the character is a newline
        {
            prntPoint.setX(5); // move point back to the very left
            prntPoint.setY(row * 20 + 15); // move down
            ++row;
        }
    }
}

QSize Widget::sizeHint() const
{
    return QSize(lineSize * 20, rowSize * 20);
}



int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Widget *w = new Widget;
    QScrollArea area;

    area.setWidget(w);
    area.show();

    //change string and other data variables
    w->changeData("1234567890\nQWERTYU123\nLETTERS123\nWORDSSS123\n"
                  "TESTING123\nFUNCTIO123\nLETTERS123\nWORDSSS123\n", 10, 8);

    return a.exec();
}

正如您所看到的那样，我们在main函数中设置的数据被截断，只打印了前7个字符和前4行，基本上取了我们在构造函数中设置的第一个字符串并获取了这个新字符串的子集打印它。

删除QScrollArea可以解决问题，但我需要为我的应用程序提供滚动功能。任何帮助将不胜感激。谢谢

QScrollArea自定义窗口小部件无法正确重新绘制

0 个答案: