日志

QT线程更新UI和QTimer定时器

已有 534 次阅读2019-3-1 10:58 |个人分类:QT编程|系统分类:兴趣爱好| 线程, QThread, 定时器, QTimer

1、在MainWindow的构造函数中创建了QTimer对象，QTimer运行在主线程中（本线程）

2、在新建线程MyThread中，想要更新UI，则发出信号，由主线程中连接的SLOT函数处理（跨线程）

//------------------------------------------------------------------------------线程头文件--------------------------------

#include <QThread>

class MyThread : public QThread

{

Q_OBJECT

public:

MyThread();

bool task_start();

bool end_request;
int task_cnt;signals:
void update_ui_signal();
private:
void run() override;

};

//------------------------------------------------------------------------------线程源文件-------------------------------

#include "mythread.h"

#include <QPushButton>
MyThread::MyThread()
{
end_request = false;
task_cnt = 0;
}
bool MyThread::task_start()
{
start();
return isRunning();
}
void MyThread::run()
{
while(!end_request)
{
      task_cnt++;
      emit update_ui_signal();                 //发出信号，通知SLOT（连接到MainWindow::update_ui_slot()）
      msleep(10);
}

}

//------------------------------------------------------------------------------UI头文件----------------------------------
#include <QMainWindow>
#include <QTimer>
#include "mythread.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_pushButton_clicked();
void update_ui_slot();
private:
Ui::MainWindow *ui;
int xCnt;
QTimer *tmr;
MyThread *thd;

};

//------------------------------------------------------------------------------UI源文件----------------------------------
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
xCnt = 0;

//连接QTimer的timeout()信号到pushButton的click(),模拟点击事件

//点击事件通过自动连接，由on_pushButton_clicked（）由处理

tmr = new QTimer(this);

connect(tmr, SIGNAL(timeout()), ui->pushButton, SLOT(click()));

tmr->start(10);

//连接QThread的update_ui_signal()信号到update_ui_slot()

thd = new MyThread();

thd->task_start();
connect(thd, SIGNAL(update_ui_signal()), this, SLOT(update_ui_slot()));
}
MainWindow::~MainWindow()
{
delete ui;
tmr->stop();
delete tmr;
tmr = nullptr;
if(thd->isRunning())
{
thd->end_request = true;
QThread::msleep(100);
}
delete thd;
thd = nullptr;
}
void MainWindow::on_pushButton_clicked()
{
xCnt++;
ui->pushButton->setText("OK ui=" + QString::number(xCnt) + ", thd=" + QString::number(thd->task_cnt));
}
void MainWindow::update_ui_slot()
{
//xCnt++;
ui->pushButton->setText("OK ui=" + QString::number(xCnt) + ", thd=" + QString::number(thd->task_cnt));
}