// 1. 继承QThread
class DemoThread : public QThread
{
    Q_OBJECT
public:
    explicit DemoThread(QObject *parent = 0);
    ~DemoThread();

protected:
    //QThread的虚函数，不能直接调用，通过start()间接调用
    void run();

signals:
	//处理完成信号
    void processFinished();
};

#endif // MYTHREAD_H

};

void DemoThread::run()
{
    // 在该函数中进行业务的耗时操作
    // doSomething
	//发送完成信号
    emit processFinished();  
}


// 2. 通过QObject::moveToThread() --- qt assistant 提供的例子
class Worker : public QObject
{
  Q_OBJECT

public slots:
  void doWork(const QString &parameter) {
      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 &);
};


// 3. 使用QtConcurrent模块
// 3.1 不需要处理结果
QtConcurrent::run(this, &Controller::doWork, params);
// 3.2 需要接受处理结果
QFutureWatcher<QVariantMap> *doWorkWatcher = new QFutureWatcher<QVariantMap>;
QFuture<QVariantMap> future = QtConcurrent::run(this, &Controller::doWork, params);
connect(doWorkWatcher, &QFutureWatcher<QVariantMap>::finished, [=]()
{
	QVariantMap result = doWorkWatcher->resultAt(0);
	doWorkWatcher->deleteLater();
});
doWorkWatcher->setFuture(future);