QT QProgressBar,QProgressDialog实例

QProgressBar类的几个重要属性:

• minimum:进度条指示的最小值；
• maximum:进度条指示的最大值；
• format:决定进度条显示文字的格式，可以有三种显示格式:"%p%"(显示完成的百分比，默认显示方式)、"%v"(显示当前的进度值)和"%m"(显示总的步进值);

设置进度条的步进范围：

QProgressBar::setRange(0, 10000);

QProgressDialog类的几个重要属性:

mininum:进度条最小值；
maximum:进度条最大值；
minimumDuration:进度条对话框出现的等待时间，若小于设定的等待时间（minimumDuration）则不出现进度条对话框；

步进值百分比计算公式:

百分比=(value() - minimum()) / (maximum() - minimum())

dialog.h

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QLabel>
#include <QLineEdit>
#include <QProgressBar>
#include <QComboBox>
#include <QPushButton>
#include <QGridLayout>

class Dialog : public QDialog
{
    
    
    Q_OBJECT

public:
    Dialog(QWidget *parent = nullptr);
    ~Dialog();
private slots:
    void startProgress();
private:
    QLabel *FileNum;
    QLineEdit *FileNumLineEdit;
    QLabel *ProgressType;
    QComboBox *comboBox;
    QProgressBar *progressBar;
    QPushButton *starBtn;
    QGridLayout *mainLayout;
};
#endif // DIALOG_H

dialog.cpp

#include "dialog.h"
#include <QProgressDialog>
#include <QFont>

Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    
    
    QFont font("ZYSong18030", 12);
    setFont(font);
    setWindowTitle("Progress");

    FileNum = new QLabel();
    FileNum->setText("文件数目: ");
    FileNumLineEdit = new QLineEdit();
    FileNumLineEdit->setText("200000");

    ProgressType = new QLabel();
    ProgressType->setText("显示类型: ");

    comboBox = new QComboBox();
    comboBox->addItem("progressBar");
    comboBox->addItem("progressDialog");
    progressBar = new QProgressBar();
    starBtn = new QPushButton();
    starBtn->setText("开始");

    mainLayout = new QGridLayout(this);
    mainLayout->addWidget(FileNum, 0, 0);
    mainLayout->addWidget(FileNumLineEdit, 0, 1);
    mainLayout->addWidget(ProgressType, 1, 0);
    mainLayout->addWidget(comboBox, 1, 1);
    mainLayout->addWidget(progressBar, 2, 0, 1, 2);
    mainLayout->addWidget(starBtn, 3, 1);
    mainLayout->setMargin(15);
    mainLayout->setSpacing(10);

    connect(starBtn, SIGNAL(clicked()), this, SLOT(startProgress()));
}

Dialog::~Dialog()
{
    
    

}

void Dialog::startProgress()
{
    
    
    bool ok;
    int num = FileNumLineEdit->text().toInt(&ok);

    if(comboBox->currentIndex() == 0) {
    
    
        progressBar->setRange(0, num);
        for(int i=1; i<num+1; i++) {
    
    
            progressBar->setValue(i);
        }
    } else if (comboBox->currentIndex() == 1) {
    
    
        QProgressDialog *progressDialog = new QProgressDialog(this);
        QFont font("ZYSong18030", 12);
        progressDialog->setFont(font);
        progressDialog->setWindowModality(Qt::WindowModal);
        progressDialog->setMinimumDuration(5);
        progressDialog->setWindowTitle("Please Wait");
        progressDialog->setLabelText("Copying...");
        progressDialog->setCancelButtonText("Cancel");
        progressDialog->setRange(0, num);
        for (int i=1; i<num+1; i++) {
    
    
            progressDialog->setValue(i);
            if (progressDialog->wasCanceled()) {
    
    
                qDebug("Progress Dialog Was Canceled!");
                return;
            }
        }
    }
}

main.cpp

#include "dialog.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    
    
    QApplication a(argc, argv);
    Dialog w;
    w.show();
    return a.exec();
}