Qt实现进度条（QProgressBar）

╰+攻爆jí腚メ 2023-02-13 04:59 16阅读 0赞

## 1、进度条的作用 ##

用于显示时间，并告诉用户当前任务的执行进展。

## 2、进度条的使用方式 ##

两种：模态方式和非模态方式
    
       模态方式：使用简单，但必须使用QApplication::processEvents()使事件循环保持正常进行状态，以保证应用不会被阻塞。
    
       非模态方式：需通过QTime实现定时设置进度条的值。

## 3、进度条的显示方式 ##

两种：1、QProgressBar，可以横向或纵向显示；2、QProgressDialog，以对话框的形式表示。

## 4、标准进度条的基本元素 ##

进度显示条、取消按钮、标签。

## 5、样例 ##

**1、头文件progressdlg.h**

#ifndef PROGRESSDLG_H
    #define PROGRESSDLG_H
     
    #include <QDialog>
     
    class QLabel;
    class QLineEdit;
    class QComboBox;
    class QProgressBar;
    class QPushButton;
    class QGridLayout;
     
    class ProgressDlg : public QDialog
    {
        
        Q_OBJECT
     
    public:
        ProgressDlg(QWidget *parent = 0);
        ~ProgressDlg();
     
    private slots:
        void startProgress();
     
    private:
        QLabel *FileNum;
        QLineEdit *FileNumLineEdit;
        QLabel *ProgressType;
        QComboBox *comboBox;
        QProgressBar *progressBar;
        QPushButton *starBtn;
        QGridLayout *mainLayout;
    };
     
    #endif // PROGRESSDLG_H

**2、源文件 progressdlg.cpp**

#include "progressdlg.h"
    #include <QFont>
    #include <QLabel>
    #include <QLineEdit>
    #include <QComboBox>
    #include <QProgressBar>
    #include <QPushButton>
    #include <QGridLayout>
    #include <QProgressDialog>
     
    ProgressDlg::ProgressDlg(QWidget *parent)
        : QDialog(parent)
    {
        
        QFont font("ZYSong18030", 12);
        setFont(font);
        setWindowTitle(tr("Progress"));
     
        FileNum = new QLabel;
        FileNum->setText(tr("File Number: "));
        FileNumLineEdit = new QLineEdit;
        FileNumLineEdit->setText(tr("100000"));
     
        ProgressType = new QLabel;
        ProgressType->setText(tr("Dispaly Type: "));
        comboBox = new QComboBox;
        comboBox->addItem(tr("progressBar"));
        comboBox->addItem(tr("progressDialog"));
     
        progressBar = new QProgressBar;
     
        starBtn = new QPushButton;
        starBtn->setText(tr("Start"));
     
        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()));
    }
     
    ProgressDlg::~ProgressDlg()
    {
        
        if(FileNum) delete FileNum;
        if(FileNumLineEdit) delete FileNumLineEdit;
        if(ProgressType) delete ProgressType;
        if(comboBox) delete comboBox;
        if(progressBar) delete progressBar;
        if(starBtn) delete starBtn;
        if(mainLayout) delete mainLayout;
    }
     
    void ProgressDlg::startProgress()
    {
        
        bool ok = false;
        int num = FileNumLineEdit->text().toInt(&ok);
     
        if (!ok)
            return ;
     
        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(tr("Please Wait"));
            progressDialog->setLabelText(tr("Copying..."));
            progressDialog->setCancelButtonText(tr("Cancel"));
            progressDialog->setRange(0, num);
            for (int i = 0; i < num + 1; ++i)
            {
        
                progressDialog->setValue(i);
                if (progressDialog->wasCanceled())
                {
        
                    delete progressDialog;
                    return ;
                }
            }
     
            delete progressDialog;
        }
    }

**3、main.cpp**

#include "progressdlg.h"
    #include <QApplication>
     
    int main(int argc, char *argv[])
    {
        
        QApplication a(argc, argv);
        ProgressDlg w;
        w.show();
     
        return a.exec();
    }

## 6、显示结果 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][b7e3ed91591a48eaa264513512ccd515.png]  
![在这里插入图片描述][4fe460e0081849f4affa28f5eb896906.png]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/f58065044fdd4ed6868deaa53a62cf46.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/377b4fb0a7654f298e9f149de4f5e92d.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0MDEzNzkw,size_16,color_FFFFFF,t_70
[b7e3ed91591a48eaa264513512ccd515.png]: https://img-blog.csdnimg.cn/b7e3ed91591a48eaa264513512ccd515.png
[4fe460e0081849f4affa28f5eb896906.png]: https://img-blog.csdnimg.cn/4fe460e0081849f4affa28f5eb896906.png