如何使用 QTimer [英] How to use QTimer

问题描述

在 Qt 中，我试图设置一个 QTimer 每秒调用一个名为更新"的函数.这是我的 .cpp 文件:

In Qt I'm trying to set a QTimer that calls a function called "update" every second. Here is my .cpp file:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTimer>
#include "QDebug"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
    timer->start(1000);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::update()
{
    qDebug() << "update";
}

和主要:

#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

项目正在构建，但它不执行更新，因为更新"行没有显示在任何地方...有人看到我做错了什么吗?

The project is being build, but it doesn't execute update, since the line "update" is not showing anywhere... Does anybody see what I´m doing wrong?

推荐答案

1. 最好让 QTimer 的父级使用 Qt 的内存管理系统.

1. It's good practice to give a parent to your QTimer to use Qt's memory management system.

update() 是一个 QWidget 函数 - 这是您要调用的函数吗?http://qt-project.org/doc/qt-4.8/qwidget.html#更新.

update() is a QWidget function - is that what you are trying to call or not? http://qt-project.org/doc/qt-4.8/qwidget.html#update.

如果数字 2 不适用，请确保您尝试触发的函数在标头中声明为插槽.

If number 2 does not apply, make sure that the function you are trying to trigger is declared as a slot in the header.

最后，如果这些都不是您的问题，那么了解您是否遇到任何运行时连接错误会很有帮助.

Finally if none of these are your issue, it would be helpful to know if you are getting any run-time connect errors.

这篇关于如何使用 QTimer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！