#ifndef DIALOG_H#define DIALOG_H #include <QDialog>#include <QLabel>#include <QPushButton>#include <QTimer>#include <QStringList> class Dialog : public QDialog{ Q_OBJECT public: Dialog(QWidget *parent = 0); ~Dialog();private slots: void on_clicked(); void on_timer();private: QLabel *label1; QPushButton *btn1; QTimer *tm; QStringList strlist;};  #endif // DIALOG_H

#include "dialog.h"#include <QVBoxLayout>#include <QFont>#include <QFile>#include <QTextStream>#include <QMessageBox> Dialog::Dialog(QWidget *parent) : QDialog(parent){ setWindowTitle(tr("幸運大抽獎"));//設(shè)置窗口標題 label1 = new QLabel; label1->setText(tr("開始幸運大抽獎")); QFont font; font.setBold(true);//設(shè)置字體為粗體 font.setPointSize(80);//設(shè)置字號 label1->setFont(font);  btn1 = new QPushButton; btn1->setText(tr("開始"));  QVBoxLayout *layout1 = new QVBoxLayout(this); layout1->addWidget(label1, 0, Qt::AlignCenter);//加入label1標簽，并且居中顯示 layout1->addWidget(btn1); // layout1->setSizeConstraint(QLayout::SetFixedSize);//設(shè)置layout大小和控件尺寸一致,使窗口不能更改大小  QFile file("student.txt"); if (file.open(QFile::ReadOnly))//以只讀的方式打開student.txt文件 {  QTextStream stream(&file);  while(!stream.atEnd())  {   strlist.append(stream.readLine());//將文件內(nèi)容放到strlist中  }  file.close(); }else {  //如果打開student.txt文件失敗,程序退出  QMessageBox::critical(this, tr("錯誤"), file.errorString());  exit(0); } tm = new QTimer(this); connect(tm, SIGNAL(timeout()), this, SLOT(on_timer())); connect(btn1, SIGNAL(clicked()), this, SLOT(on_clicked()));} Dialog::~Dialog(){ } void Dialog::on_clicked(){ static bool status = true; if (status) {  btn1->setText("停止");//如果isok為true,設(shè)置按鈕標題為“停止”  tm->start(50);//啟動計時器,沒0.05秒執(zhí)行一次on_timer函數(shù)  status = false; }else {  btn1->setText("開始");//如果isok為false,設(shè)置按鈕標題為“開始”  tm->stop();//停止計時器  status = true; }} void Dialog::on_timer(){ if (strlist.count() == 0) {  return ;//如果strlist中沒有內(nèi)容，函數(shù)返回 }  static int i = 0; label1->setText(strlist[i]);//從0到strlist.count(),循環(huán)顯示strlist中每一項的內(nèi)容 i++; if (i >= strlist.count()) {  i = 0; }}