从其他线程调用插槽

当使用 Qt 事件循环执行操作并且非 Qt-saavy 用户需要与该事件循环交互时，编写插槽以处理来自另一个线程的常规调用可以简化其他用户的操作。

main.cpp 中：

#include "OperationExecutioner.h"
#include <QCoreApplication>
#include <QThread>

int main(int argc, char** argv)
{
    QCoreApplication app(argc, argv);

    QThread thrd;
    thrd.setObjectName("thrd");
    thrd.start();
    while(!thrd.isRunning())
        QThread::msleep(10);

    OperationExecutioner* oe = new OperationExecutioner;
    oe->moveToThread(&thrd);
    oe->doIt1(123,'A');
    oe->deleteLater();
    thrd.quit();
    while(!thrd.isFinished())
        QThread::msleep(10);

    return 0;
}

OperationExecutioner.h：

#ifndef OPERATION_EXECUTIONER_H
#define OPERATION_EXECUTIONER_H

#include <QObject>

class OperationExecutioner : public QObject
{
    Q_OBJECT
public slots:
    void doIt1(int argi, char argc);
};

#endif  // OPERATION_EXECUTIONER_H

OperationExecutioner.cpp：

#include "OperationExecutioner.h"
#include <QMetaObject>
#include <QThread>
#include <QDebug>

void OperationExecutioner::doIt1(int argi, char argc)
{
    if (QThread::currentThread() != thread()) {
        qInfo() << "Called from thread" << QThread::currentThread();
        QMetaObject::invokeMethod(this, "doIt1", Qt::QueuedConnection,
                                  Q_ARG(int,argi), Q_ARG(char,argc));
        return;
    }

    qInfo() << "Called from thread" << QThread::currentThread()
            << "with args" << argi << argc;
}

OperationExecutioner.pro：

HEADERS += OperationExecutioner.h
SOURCES += main.cpp OperationExecutioner.cpp
QT -= gui