一个std::thread在成员函数执行耗时操作的例子

#include <QLabel>
#include <QPushButton>
#include <QVBoxLayout>
#include <thread>
#include <chrono>
#include <mutex>
#include <QDebug>

class MyWidget : public QWidget
{
    Q_OBJECT
public:
    MyWidget(QWidget *parent = nullptr) : QWidget(parent)
    {
        QVBoxLayout *layout = new QVBoxLayout(this);
        label = new QLabel("Result: ", this);
        layout->addWidget(label);

        QPushButton *button = new QPushButton("Start Task", this);
        layout->addWidget(button);
        layout->addWidget(new QPushButton("helloworld"));

        connect(button, &QPushButton::clicked, this, &MyWidget::startTask);
        connect(this,&MyWidget::resultReady,this,&MyWidget::updateResult);
    }

    ~MyWidget()
    {
        if (workerThread.joinable())
        {
            {
                std::lock_guard<std::mutex> lock(mtx);
                running = false;
            }
            workerThread.join();
        }
    }

signals:
    void resultReady(int);

private slots:
    void updateResult(int result)
    {
        qDebug()<<"执行一次耗时操作";
        label->setText("Result: " + QString::number(result));
    }

    void startTask()
    {
        if (!workerThread.joinable())//线程未在执行
        {
            running = true;
            workerThread = std::thread(&MyWidget::timeConsumingTask, this);
        }
    }

private:
    QLabel *label;
    std::thread workerThread;
    std::mutex mtx;
    bool running{false};

    void timeConsumingTask()
    {
        for(int i = 0;i < 20;++i)
        {
            if(running)
            {
                // 模拟耗时操作
                std::this_thread::sleep_for(std::chrono::seconds(3));

                std::lock_guard<std::mutex> lock(mtx);
                emit resultReady(i);
            }
        }
    }
};

不卡界面