Question

我需要使用按钮非常频繁地启动和停止线程..我正在使用Qt。最近我学会了创建一个worker的QObject并将其移动到QThread的对象，作为在Qt中实现线程的正确方法。以下是我的实施......

Worker.h

class worker : public QObject
{
    Q_OBJECT
public:
    explicit worker(QObject *parent = 0);
    void StopWork();
    void StartWork();
    bool IsWorkRunning();

signal:
    void SignalToObj_mainThreadGUI();

public slots:
    void do_Work();

private:
    void Sleep();

    volatile bool running,stopped;
    QMutex mutex;
    QWaitCondition waitcondition;
};

Worker.cpp

 worker::worker(QObject *parent) :
    QObject(parent),stopped(false),running(false)
{
}

void worker::do_Work()
{
    running = true;
    while(!stopped)
    {
        emit SignalToObj_mainThreadGUI();
        Sleep();
    }
}

void worker::Sleep()
{
    mutex.lock();
    waitcondition.wait(&mutex,10);
    mutex.unlock();
}

void worker::StopWork()
{
    mutex.lock();
    stopped = true;
    running = false;
    mutex.unlock();
}

void worker::StartWork()
{
    mutex.lock();
    stopped = false;
    running = true;
    mutex.unlock();
}

bool worker::IsWorkRunning()
{
    return running;
}

MainWindow.h

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

public slots:

private slots:
    void on_pushButton_push_to_start_clicked();

    void on_pushButton_push_to_stop_clicked();

private:

    Ui::MainWindow *ui;
    worker *myWorker;
    QThread *WorkerThread;
};

MainWindow.cpp

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    myWorker = new worker;
    WorkerThread = new QThread;
    myWorker.moveToThread(WorkerThread);

    QObject::connect(WorkerThread,SIGNAL(started()),myWorker,SLOT(do_Work()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_push_to_start_clicked()
{
    if(!myWorker.IsWorkRunning())
       {
         myWorker->StartWork();
         WorkerThread->start();
       }
}

void MainWindow::on_pushButton_push_to_stop_clicked()
{
  if(myWorker.IsWorkRunning())
     {
       myWorker->StopWork();
       WorkerThread->quit();
     }
}

最初应用程序工作正常但是在按钮的某些操作之后打开和关闭线程的工作会出现以下错误...

QObject :: killTimers（）：无法从其他线程停止计时器

我对这个错误感到很困惑......我是否需要将启动/停止功能实现为信号和插槽而不是类的成员函数？

Answer 1

不要启动和停止WorkerThread。让它继续运行。另外，将StartWork()和StopWork()方法移至公共广告位部分。你根本不需要互斥锁。

<强> Worker.h

class worker : public QObject
{
  Q_OBJECT
public:
  explicit worker(QObject *parent = 0);

signal:
  void SignalToObj_mainThreadGUI();
  void running();
  void stopped();

public slots:
  void StopWork();
  void StartWork();

private slots:
  void do_Work();

private:
  volatile bool running,stopped;
};

<强> Worker.cpp

worker::worker(QObject *parent) :
  QObject(parent), stopped(false), running(false)
{}

void worker::do_Work()
{
  emit SignalToObj_mainThreadGUI();

  if ( !running || stopped ) return;

  // do important work here

  // allow the thread's event loop to process other events before doing more "work"
  // for instance, your start/stop signals from the MainWindow
  QMetaObject::invokeMethod( this, "do_Work", Qt::QueuedConnection );
}

void worker::StopWork()
{
  stopped = true;
  running = false;
  emit stopped();
}

void worker::StartWork()
{
  stopped = false;
  running = true;
  emit running();
  do_Work();
}

<强> MainWindow.h

namespace Ui {
  class MainWindow;
}

class MainWindow : public QMainWindow
{
  Q_OBJECT
public:
  explicit MainWindow(QWidget *parent = 0);
  ~MainWindow();

signals:
  void startWork();
  void stopWork();

private slots:
  void on_pushButton_push_to_start_clicked();
  void on_pushButton_push_to_stop_clicked();

private:
  Ui::MainWindow *ui;
  worker *myWorker;
  QThread *WorkerThread;

};

<强> MainWindow.cpp

MainWindow::MainWindow(QWidget *parent) :
  QMainWindow(parent),
  ui(new Ui::MainWindow)
{
  ui->setupUi(this);

  myWorker = new worker;
  WorkerThread = new QThread;
  myWorker.moveToThread(WorkerThread);

  connect( this, SIGNAL(startWork()), myWorker, SLOT(StartWork()) );
  connect( this, SIGNAL(stopWork()), myWorker, SLOT(StopWork()) );
}

void MainWindow::on_pushButton_push_to_start_clicked()
{
  emit startWork();
}

void MainWindow::on_pushButton_push_to_stop_clicked()
{
  emit stopWork();
}

如何实现频繁启动/停止线程（QThread）

1 个答案: