qt5开发--线程的使用

方法1

??另一种单独在线程中执行的方式是继承QThread后重新实现run()函数(run函数内用户的执行操作)。

• 示例:

class WorkerThread : public QThread
{
    Q_OBJECT
    void run() override {
        QString result;
        /* ... here is the expensive or blocking operation ... */
        emit resultReady(result);
    }
signals:
    void resultReady(const QString &s);
};

void MyObject::startWorkInAThread()
{
    WorkerThread *workerThread = new WorkerThread(this);
    connect(workerThread, &WorkerThread::resultReady, this, &MyObject::handleResults);
    connect(workerThread, &WorkerThread::finished, workerThread, &QObject::deleteLater);
    workerThread->start();
}

方法2

??一个QThread实例管理程序中的一个线程。QThread的执行开始于run()。默认情况下，run()通过调用exec()启动事件循环，并在线程内运行Qt事件循环。
??你可以使用QObject::moveToThread()将工作对象移动到线程中使用。

• 示例：

class Worker : public QObject
{
    Q_OBJECT
public slots:
    void doWork(const QString ¶meter) {
        QString result;
        /* ... here is the expensive or blocking operation ... */
        emit resultReady(result);
    }

signals:
    void resultReady(const QString &result);
};

class Controller : public QObject
{
    Q_OBJECT
    QThread workerThread;
public:
    Controller() {
        Worker *worker = new Worker;
        worker->moveToThread(&workerThread);
        connect(&workerThread, &QThread::finished, worker, &QObject::deleteLater);
        connect(this, &Controller::operate, worker, &Worker::doWork);
        connect(worker, &Worker::resultReady, this, &Controller::handleResults);
        workerThread.start();
    }
    
    ~Controller() {
        workerThread.quit();
        workerThread.wait();
    }
    
public slots:
    void handleResults(const QString &);
    
signals:
    void operate(const QString &);
};