QTimer::singleShot的作用

QTimer::singleShot的作用

1.用作单次定时启动某类函数

2.线程操作，主线程操作某个线程类，为了让主线程调用某类接口是子线程里去执行的，可以在调用接口使用QTimer::singleShot去调用想让子线程运行的接口（在调用接口前，必须是该类线程已经movethread）

例子:

main.cpp

#include <QCoreApplication>
#include "amainwork.h"
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    {
        AMainWork mainwork;
        mainwork.init();
        QThread::sleep(10);
        qDebug() << "main";
    }
    return a.exec();
}

amainwork

#ifndef AMAINWORK_H
#define AMAINWORK_H
#include "athreadtestobj.h"
#include <QObject>
#include <QScopedPointer>

class AMainWork : public QObject
{
    Q_OBJECT
public:
    explicit AMainWork(QObject *parent = 0);
    ~AMainWork();
    void init();
signals:

public slots:
    void slotInit();

private:
    QScopedPointer<AThreadTestObj> m_threadTestObj;
};

#endif // AMAINWORK_H

#include "amainwork.h"
#include <QTimer>
#include <QDebug>
#include <QThread>

AMainWork::AMainWork(QObject *parent) : QObject(parent)
{

}

AMainWork::~AMainWork()
{
    m_threadTestObj->deinit();
}

void AMainWork::init()
{
    QTimer::singleShot(0,this,SLOT(slotInit()));
    qDebug() << "init " << QThread::currentThread();
    m_threadTestObj.reset(new AThreadTestObj());
    m_threadTestObj->init();
    m_threadTestObj->start();
}

void AMainWork::slotInit()
{
    qDebug() << "slotinit " << QThread::currentThread();
}

athreadtestobj

#ifndef ATHREADTESTOBJ_H
#define ATHREADTESTOBJ_H
#include "athread.h"

#include <QObject>
#include <QTimer>
#include <QThread>
#include <QTimer>

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

    virtual void init();
    virtual void deinit();
    virtual bool start();
    virtual bool stop();

protected:
    virtual void initInThread();
    virtual void deinitInThread();

signals:
    void sigOndeinit();

public slots:
    void sltInit();
    void sltDeinit();
    void sltOnTimer();

private:
    AThread<AThreadTestObj> m_thread;
    friend class AThread<AThreadTestObj>;
    QTimer * m_pTimer;
};
#endif // ATHREADTESTOBJ_H

#include "athreadtestobj.h"
#include <QDebug>
#include <QEventLoop>

AThreadTestObj::AThreadTestObj(QObject *parent) : QObject(parent)
{
}

void AThreadTestObj::init()
{
    m_thread.setObjectName("AThreadTestObj");

    m_thread.bind(this);
}

void AThreadTestObj::deinit()
{
    stop();
}

bool AThreadTestObj::start()
{
    QTimer::singleShot(0,this,SLOT(sltInit()));
    m_thread.start();
    qDebug() << "AThreadTestObj::start " << QThread::currentThread();
    return true;
}

bool AThreadTestObj::stop()
{
    qDebug() << "AThreadTestObj::stop " << QThread::currentThread();
    QEventLoop loop;
    connect(this, SIGNAL(sigOndeinit()), &loop, SLOT(quit()));
    QTimer::singleShot(0, this, SLOT(sltDeinit()));
    loop.exec();

    m_thread.quit();
    return true;
}

void AThreadTestObj::initInThread()
{
    qDebug() << "AThreadTestObj::initInThread " << QThread::currentThread();
}

void AThreadTestObj::deinitInThread()
{
    qDebug() << "AThreadTestObj::deinitInThread " << QThread::currentThread();
}

void AThreadTestObj::sltInit()
{
    m_pTimer = new QTimer(this);
    connect(m_pTimer, SIGNAL(timeout()), this, SLOT(sltOnTimer()));
    m_pTimer->start(600);
}

void AThreadTestObj::sltDeinit()
{
    qDebug() << "AThreadTestObj::sltDeinit " << QThread::currentThread();
    if(nullptr != m_pTimer)
    {
        m_pTimer->stop();
        delete m_pTimer;
        m_pTimer = nullptr;
    }

    emit sigOndeinit();
}

void AThreadTestObj::sltOnTimer()
{
    qDebug() << "AThreadTestObj::sltOnTimer " << QThread::currentThread();
}

athread.h

#ifndef ATHREAD_H
#define ATHREAD_H
#include <QThread>

template<typename T>
class AThread : public QThread
{
public:
    explicit AThread(QObject *parent = Q_NULLPTR)
        :QThread(parent),m_pt(nullptr){}
    ~AThread(){}

    void bind(T* pt)
    {
        m_pt = pt;
        m_pt->moveToThread(this);
    }
protected:
    virtual void run()
    {
        if(nullptr==m_pt) return ;
        m_pt->initInThread();
        exec();
        m_pt->deinitInThread();
    }
public:
    T* m_pt;
};

#endif // ATHREAD_H