创建子进程类

普通的长时间操作界面容易卡死, 体验非常不好,为了提升体验, 所以将需要较长时间响应的事件都放到了子线程中执行, 这样主线程就不会出现假死的状态

方法1(继承QThread):

.h [头文件]

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QThread>

class Generate : public QThread
{
    Q_OBJECT
public:
    explicit Generate(QObject* parent = nullptr);// 直接使用qt的类生成,这里没有默认的空指针,new的时候会报错,需要设置成nullptr

protected:
    void run(); // 重写run函数

signals:
    void curNumber(int num);// 自定义信号, 传递数据
    void curimg(QImage* img); // 传递图片, 如果是自定义的结构, 需要注册类型:qRegisterMetaType<int>("int")  [int根据自己的类型设置];

public slots:
};

#endif // MYTHREAD_H

.c[源文件]

#include "mythread.h"
#include "qdebug.h"

Generate::Generate(QObject* parent) : QThread(parent)
{

}

void Generate::run()
{
    qDebug() << "current Thread id is: " << QThread::currentThread();

    int num = 0;
    while (1)
    {
        emit curNumber(num++);
        if (num == 999)
        {
            qDebug() << " sub Thread is finished...";
            break;
        }
        QThread::usleep(1);
    }
}

mainwindow.c主线程

#include "qtwidgetsapplication_thread.h"
#include "MyCreate.h"



#include <qdebug.h>

QtWidgetsApplication_Thread::QtWidgetsApplication_Thread(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);
    qDebug() << "main thread is : " << QThread::currentThread();
    
    // 将刚才的创建的类实例化
    Generate * subThread_A = new Generate ;
   


    // 绑定信号和槽
    connect(subThread_A, &Generate ::curNumber, this, [=](int num) {
        ui.label->setNum(num);
        });
   


    // 启动线程
    connect(ui.pushButton, &QPushButton::clicked, this, [=]() {
        subThread_A->start();
        });
    
   

}

方法二(moveToThread):

这种方法相对来说更加灵活 打开创建类的头文件MyThread.h

修改MyThread(QObject *parent);—–>MyThread(QObject *parent=nullptr);, 不修改在new的时候会报错 [类不存在默认构造函数]

修改完成后如下

#include <QObject>

class MyThread  : public QObject
{
    Q_OBJECT
    
public:
    MyThread(QObject *parent=nullptr);
    ~MyThread();

    // create working function to do sth what you want
    void working(); //线程中执行的代码写到working中,这个函数名随意

signals:
    // create a signal to kick the thread
    void signal_hello(int count); // 设置一个触发信号, count为传递的变量, 将这个变量用来讲子线程和主线程之间进行传递数据.
};

打开创建类的源文件MyThread.cpp

将刚才创建的头文件进行实现 这个程序的作用主要是将子线程中的变量发送到主线程进行显示

#include "MyThread.h"

#include "qdebug.h"
#include "qthread.h"

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

MyThread::~MyThread()
{}

void MyThread::working()
{
    int count = 0;
    while (1) {
        // kick the signal, and post the data [count] by this signal
        emit signal_hello(++count);  // 将信号发送, 并将数据发送到主线程
        if (count == 999) {
            qDebug() << "sub thread is stoped:";
            break;
        }
        qDebug() << "current thread is:" << QThread::currentThread;
    }
}

进入到主线程进行实现mainwindow.cpp

MyThread* work = new MyThread;
QThread* thread_c = new QThread;

work->moveToThread(thread_c);                    // 放到新线程中
thread_c->start();                               // 启动线程

connect(ui.pushButton, &QPushButton::clicked, work, &MyThread::working);// 按钮点击信号
connect(work, &MyThread::signal_hello, this, [=](int count) {
       ui.label->setNum(count);
       });  // 界面刷新信号