QThread 和窗口之间的通信通常通过信号和槽机制来实现

也可以直接通过调用线程中的值

效果图(Dialog To hello; TextLabel To hello)

在主窗口类中创建线程实例，并连接线程发出的信号到主窗口的槽函数。

.h

#ifndef TESTAPP_H
#define TESTAPP_H

#include <QDialog>
#include <QThread>

namespace Ui {
class TestApp;
}

class TestAppThread : public QThread
{
    Q_OBJECT

public:
    QString threadValue;

signals:
    void valueSignals(QString valueStr);
    
protected:
    void run() override;
};

class TestApp : public QDialog
{
    Q_OBJECT

public:
    explicit TestApp(QWidget *parent = nullptr);
    ~TestApp();

    TestAppThread *m_testAppThread;

public slots:
    void valueReceiver(QString valueStr);
    
private:
    Ui::TestApp *ui;
};

#endif // TESTAPP_H

.cpp

#include "testapp.h"
#include "ui_testapp.h"

TestApp::TestApp(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::TestApp)
{
    ui->setupUi(this);
    m_testAppThread = new TestAppThread;
	m_testAppThread->threadValue = "hello";
    connect(m_testAppThread,&TestAppThread::valueSignals,this,&TestApp::valueReceiver);
	m_testAppThread->start();
}

TestApp::~TestApp()
{
    m_testAppThread->quit();
    m_testAppThread->wait();
    delete m_testAppThread;
    delete ui;
}

void TestAppThread::run()
{
    emit valueSignals(threadValue);
}

void TestApp::valueReceiver(QString valueStr)
{
    this->setWindowTitle(m_testAppThread->threadValue);
    ui->label->setText(valueStr);
}

此案例为部分功能点的记录，结合点击按钮弹出对话框使用线程处理数据并在Dialog上显示。

也希望对大家有所帮助！！！