用以实现一个读取文件进度条的功能

1.新建一个无ui界面的工程，其基类为dialog对话框类

2.代码实现

dialog.h

#ifndef DIALOG_H #define DIALOG_H #include <QDialog> #include <QLabel> #include <QProgressBar> #include <QPushButton> class Dialog : public QDialog { Q_OBJECT public: Dialog(QWidget *parent = 0); ~Dialog(); private slots: void startProgress(); //定义一个槽函数 private: QLabel * fileNum; //控件声明 QProgressBar * progressBar; //控件声明 QPushButton * startBtn; //控件声明 }; #endif // DIALOG_H

dialog.cpp

#include "dialog.h" Dialog::Dialog(QWidget *parent) : QDialog(parent) { this->setWindowTitle(tr("进度条")); fileNum = new QLabel(this); fileNum->setText(tr("复制文件数目:0")); fileNum->setGeometry(20,10,200,18); progressBar = new QProgressBar(this); progressBar->setGeometry(20,35,200,10); startBtn = new QPushButton(this); startBtn->setText(tr("开始")); startBtn->setGeometry(20,55,80,30); //连接信号与槽 connect(startBtn,SIGNAL(clicked()),this,SLOT(startProgress())); } Dialog::~Dialog() { } //槽函数实现 void Dialog::startProgress() { progressBar->setRange(0,100000); //设置进度条的范围 for(int i = 1; i <= 100000; i++) { progressBar->setValue(i); QString str = QString("%1").arg(i); str = "复制文件数目: " +str; fileNum->setText(str); } }

3.效果展示

4.不足与需改进之处

1.进程过快。效果不宜呈现，可以将进度条的值调大一点

2.后面可以引入QTimer定时器功能，以实现文件复制

5.改进之后

progressbar.h

#ifndef PROGRESSBAR_H #define PROGRESSBAR_H #include <QMainWindow> #include <QProgressBar> class ProgressBar : public QMainWindow { Q_OBJECT public: ProgressBar(QWidget *parent = 0); ~ProgressBar(); }; //新建类 class QString; class Progressbar : public QProgressBar { Q_OBJECT public: Progressbar(QWidget *parent = 0):QProgressBar(parent){} QString strText; public slots: void stepOne(); }; #endif // PROGRESSBAR_H

progressbar.cpp

#include "progressbar.h" #include <QString> ProgressBar::ProgressBar(QWidget *parent) : QMainWindow(parent) { } ProgressBar::~ProgressBar() { } void Progressbar::stepOne() { if(this->value()+1 <= this->maximum()) { this->setValue(this->value() + 1); strText = "进度条 : " + this->text(); this->setWindowTitle(strText); } else { this->setValue(this->minimum()); } }

main.cpp

#include "progressbar.h" #include <QApplication> #include <QTimer> int main(int argc, char *argv[]) { QApplication a(argc, argv); ProgressBar w; w.show(); //进度条设置 Progressbar * progress = new Progressbar; progress->setWindowTitle("进度条"); progress->resize(400,40); progress->setMaximum(100); progress->setMinimum(0); progress->setValue(0); //设置一个定时器 QTimer *timer = new QTimer; timer->start(500); QObject::connect(timer, SIGNAL(timeout()), progress, SLOT(stepOne())); progress->show(); return a.exec(); }

6.效果展示

改进版本参考链接：http://blog.chinaunix.net/uid-27225886-id-3352398.html