自定义自适应内容的Label

来源：互联网发布：tensorflow constant 编辑：程序博客网时间：2024/05/16 04:38

头文件：

#ifndef ELIDEDLABEL_H#define ELIDEDLABEL_H#include <QFrame>#include <QRect>#include <QResizeEvent>#include <QString>#include <QWidget>class ElidedLabel : public QFrame{    Q_OBJECT    Q_PROPERTY(QString text READ text WRITE setText)    Q_PROPERTY(bool isElided READ isElided)public:    ElidedLabel(QWidget *parent = 0);    void setText(const QString &text);    const QString & text() const { return content; }    bool isElided() const { return elided; }protected:    void paintEvent(QPaintEvent *event);signals:    void elisionChanged(bool elided);private:    bool elided;    QString content;};#endif // TEXTWRAPPINGWIDGET_H

源文件：

#include <QPainter>#include <QTextLayout>#include <QDebug>ElidedLabel::ElidedLabel(QWidget *parent)    : QFrame(parent)    , elided(false){    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);}void ElidedLabel::setText(const QString &newText){//    setToolTip(newText);    content = newText;    update();}void ElidedLabel::paintEvent(QPaintEvent *event){    QFrame::paintEvent(event);    QPainter painter(this);    QFontMetrics fontMetrics = painter.fontMetrics();    bool didElide = false;    int lineSpacing = fontMetrics.lineSpacing();    int y = 0;    QTextLayout textLayout(content, painter.font());    textLayout.beginLayout();    forever {        QTextLine line = textLayout.createLine();        if (!line.isValid())            break;        line.setLineWidth(width());        int nextLineY = y + lineSpacing;        if (height() >= nextLineY + lineSpacing) {            line.draw(&painter, QPoint(0, y));            y = nextLineY;        } else {            QString lastLine = content.mid(line.textStart());            QString elidedLastLine = fontMetrics.elidedText(lastLine, Qt::ElideRight, width());            painter.drawText(QPoint(0, y + fontMetrics.ascent()), elidedLastLine);            line = textLayout.createLine();            didElide = line.isValid();            break;        }    }    textLayout.endLayout();    if (didElide != elided) {        elided = didElide;        emit elisionChanged(didElide);    }}

文本内容随着控件的大小改变，可获取改变前的文本。

下面附上改变文本长度的代码，适合各种控件：

QFont font(ui->_signIn->font());QFontMetrics fm(font);ui->_signIn->setText(fm.elidedText(QString(signIn.c_str()),                                           Qt::ElideRight, ui->_signIn->width()));