背景：最近在写一个删除90天数据显示进度的功能，实现思路是：通过信号槽捕获当前进度值实现。

 备注：点击start按钮，开始更新进度条，直到100（每隔1s进行更新）

举个栗子：

1、mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QThread>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);connect(ui->pushButton,&QPushButton::clicked,this,&MainWindow::close);connect(ui->pushButton1,&QPushButton::clicked,this,&MainWindow::on_startProcess);void (MyThread::*rmsgSignal)(int) = &MyThread::msgSignal;connect(&thread,rmsgSignal,this,&MainWindow::on_setProcess);ui->progressBar->setRange(0,100);}MainWindow::~MainWindow()
{delete ui;
}//开启线程
void MainWindow::on_startProcess(){thread.start();}//设置进度条参数
void MainWindow::on_setProcess(int v){ui->progressBar->setValue(v);
}

2、mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <mythread.h>#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();MyThread thread;void on_startProcess();void on_setProcess(int v);private:Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

3、mythread.cpp

#include "mythread.h"MyThread::MyThread()
{}//重写run方法
void MyThread::run(){for(int i = 1;i<=100;i++){QThread::msleep(1000);emit msgSignal(i);}
}

4、MyThread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QThread>class MyThread: public QThread{Q_OBJECT
public:MyThread();void run() override;signals:void msgSignal(int a);
};#endif // MYTHREAD_H

5、main.cpp

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

6、mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0"><class>MainWindow</class><widget class="QMainWindow" name="MainWindow"><property name="geometry"><rect><x>0</x><y>0</y><width>800</width><height>600</height></rect></property><property name="windowTitle"><string>MainWindow</string></property><widget class="QWidget" name="centralwidget"><widget class="QWidget" name="verticalLayoutWidget"><property name="geometry"><rect><x>320</x><y>140</y><width>160</width><height>80</height></rect></property><layout class="QVBoxLayout" name="verticalLayout"><item><widget class="QPushButton" name="pushButton"><property name="text"><string>close</string></property></widget></item><item><widget class="QPushButton" name="pushButton1"><property name="text"><string>start</string></property></widget></item><item><widget class="QProgressBar" name="progressBar"><property name="value"><number>0</number></property><property name="format"><string>%v%</string></property></widget></item></layout></widget></widget><widget class="QMenuBar" name="menubar"><property name="geometry"><rect><x>0</x><y>0</y><width>800</width><height>23</height></rect></property></widget><widget class="QStatusBar" name="statusbar"/></widget><resources/><connections/>
</ui>

7、结果
注：视频为测试结果，仅录制部分作为参考