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实现一个标签内的字从右向左滚动。新建一个widget窗体，在上面放一个标签。

widget.ui

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<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Widget</class>
 <widget class="QWidget" name="Widget">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>800</width>
    <height>600</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Widget</string>
  </property>
  <widget class="QLabel" name="label">
   <property name="geometry">
    <rect>
     <x>210</x>
     <y>220</y>
     <width>331</width>
     <height>211</height>
    </rect>
   </property>
   <property name="font">
    <font>
     <pointsize>12</pointsize>
     <bold>true</bold>
    </font>
   </property>
   <property name="frameShape">
    <enum>QFrame::Shape::Box</enum>
   </property>
   <property name="text">
    <string>TextLabel</string>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

widget.h

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#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

QT_BEGIN_NAMESPACE
namespace Ui {
class Widget;
}
QT_END_NAMESPACE

class Widget : public QWidget

{

    Q_OBJECT

public:

    explicit Widget(QWidget *parent = 0);

    ~Widget();

    void setText(const QString &newText);

private:

    Ui::Widget *ui;

    int myTimerId;

    QString str; //存储显示字符串

    QString tempStr;

protected:

    void timerEvent(QTimerEvent *event);
};
#endif // WIDGET_H

widget.cpp

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#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :

    QWidget(parent),

    ui(new Ui::Widget)

{

    ui->setupUi(this);

    setFocus();

    myTimerId=startTimer(300);

}

Widget::~Widget()

{

    delete ui;

}

void Widget::setText(const QString &newText)

{

    str=newText;

    tempStr=str.leftJustified(str.length()*2-1,' ');

}

void Widget::timerEvent(QTimerEvent *event)

{

    if(event->timerId()==myTimerId)

    {

        tempStr=tempStr.mid(1)+tempStr.left(1);

        ui->label->setText(tempStr.mid(0,str.length()));

        this->update();

    }

}

main.cpp

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#include "widget.h"

#include <QApplication>

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

    w.setText(QObject::tr("Winter is coming"));//要显示的字符串
    w.show();
    return a.exec();
}

MoveLabelTest.pro

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QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    widget.cpp

HEADERS += \
    widget.h

FORMS += \
    widget.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target