Qt 线程初识别

Qt有两种多线程的方法，其中一种是继承QThread的run函数，另外一种是把一个继承于QObject的类转移到一个Thread里。 
这里我使用的是继承的方法使用线程花一个"复杂"图片的例子：

myThread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H
 
#include <QObject>
#include <Qimage>
 
class myThread : public QObject
{
    Q_OBJECT
public:
    explicit myThread(QObject *parent = );
 
    //线程处理函数
    void drawImage();
 
signals:
    void updateImage(QImage temp);
 
public slots:
};
 
#endif // MYTHREAD_H

myThread.cpp

#include "myThread.h"
#include <QPainter>
#include <QPen>
#include <QBrush>
 
myThread::myThread(QObject *parent) : QObject(parent)
{
 
}
 
void myThread::drawImage()
{
    //定义一个绘图设备
    QImage image(,,QImage::Format_ARGB32);
 
    QPainter p(&image);
 
    QPen pen;
    pen.setWidth();
    p.setPen(pen);
    QBrush brush;
    brush.setStyle(Qt::SolidPattern);
    brush.setColor(Qt::blue);
    p.setBrush(brush);
 
    QPoint a[] = { QPoint(qrand()%,qrand()%),
                   QPoint(qrand()%,qrand()%),
                   QPoint(qrand()%,qrand()%),
                   QPoint(qrand()%,qrand()%),
                   QPoint(qrand()%,qrand()%)  };
 
    p.drawPolygon(a,);
 
    emit updateImage(image);
}

widget.h

#ifndef WIDGET_H
#define WIDGET_H
 
#include <QWidget>
#include <QThread>
#include <Qimage>
#include "myThread.h"
 
namespace Ui {
class Widget;
}
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    explicit Widget(QWidget *parent = );
    ~Widget();
    void paintEvent(QPaintEvent *);
 
    void getImage(QImage temp); //槽函数
    void dealClose();
 
private:
    Ui::Widget *ui;
    QImage image;
    myThread *myT;
    QThread *thread2;
};
 
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QPainter>
#include <QTimer>
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
 
    myT = new myThread;
    thread2 = new QThread(this);
    myT->moveToThread(thread2);
    thread2->start();
 
    QTimer *timer = new QTimer(this);
    timer->start();
    connect(timer,&QTimer::timeout,myT,&myThread::drawImage);
 
    connect(ui->pushButton,&QPushButton::pressed,myT,&myThread::drawImage);
    connect(myT,&myThread::updateImage,this,&Widget::getImage);
 
    connect(this,&Widget::destroyed,this,&Widget::dealClose);
}
 
void Widget::dealClose()
{
    thread2->quit();
    thread2->wait();
 
    thread2->deleteLater();
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::getImage(QImage temp)
{
    image = temp;
    update();
}
 
void Widget::paintEvent(QPaintEvent *)
{
    QPainter p(this);
    p.drawImage(,,image);
}

main.cpp

#include "widget.h"
#include <QApplication>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
 
    return a.exec();
}