在Qt / C ++中替换睡眠函数 [英] Substitute for sleep function in Qt/C++

问题描述

所以我写一个程序，显示一个单词的每个字母1秒，字母之间有1秒的间隔。 （这是1级的拼写练习）。我目前正在使用睡眠功能暂停程序1秒钟，然后再更新。之后，它显示单词一秒，然后删除它。

So I am writing a program that displays each letter of a word for 1 second with a 1 second interval between the letters. (It's for a spelling exercise for grade 1). I am currently using the sleep function to "pause" the program for 1 second before it "updates" again. After that it displays the word for a second and then removes it. I repaint before the sleep function, else it does not seem to update in time.

这是基本的功能：

QString word = "apple";
QThread thread;

for(int i = 0; i < word.size(); i++)
{
    ui->label1->setText(word[i]);
    ui->label1->repaint();
    thread.sleep(1);
    ui->label1->setText("");
    thread.sleep(1);
}

ui->label1->setText(word);
ui->label1->repaint();
thread.sleep(1);
ui->label1->setText("");

这很好，除了程序停止响应（即使我可以看到正确的输出仍然显示）直到整个函数完成执行，然后它再次工作正常。有没有另一种方式，我可以完成这个目标，而不使用睡眠？我对Qt很新。

This works fine, except the program stops responding (even though I can see the correct output is still displaying) until the whole function is done executing then it works fine again. Is there another way I can accomplish this goal without using sleep? I am quite new to Qt.

我更新了。我做了一个新类，将处理的定时器，但它似乎没有实际连接信号和插槽。这是.h文件：

Update I made. I made a new class that will handle the timer, but it does not seem to actually connect the signal and slot. Here is the .h file:

#ifndef TIMERDISPLAY_H
#define TIMERDISPLAY_H

#include <QTimer>
#include <QObject>

class TimerDisplay:public QObject
{
    Q_OBJECT

public:
    TimerDisplay();

public slots:
    void expired();

private:
    QTimer timer;
};

#endif // TIMERDISPLAY_H

和.cpp文件：

#include "timerdisplay.h"
#include <QDebug>

TimerDisplay::TimerDisplay()
{
    connect(&timer, SIGNAL(timeout()), this, SLOT(expired()));
    timer.setSingleShot(false);
    timer.setInterval(1000);
    timer.start();
}

void TimerDisplay::expired()
{
    qDebug()<<"timer expired";
}

推荐答案

使用 QTimer 或 QElapsedTimer 如果您需要更高的精度。

Use QTimer or QElapsedTimer if you need more precision.

#include <QTimer>
#include <QCoreApplication>
#include <QString>
#include <QTextStream>
#include <QDebug>

int main(int argc, char **argv)
{
    QCoreApplication application(argc, argv);
    QTimer timer;
    QTextStream textStream(stdout);
    QString word = "apple";
    int i = 0;
    QObject::connect(&timer, &QTimer::timeout, [&textStream, word, &i] () {
        if (i < word.size()) {
            textStream << word.at(i) << flush;
            ++i;
        }
    });
    timer.start(1000);
    return application.exec();
}

main.pro

main.pro

TEMPLATE = app
TARGET = main
QT = core
CONFIG += c++11
SOURCES += main.cpp

构建并运行

Build and Run

qmake && make && ./main

输出

Output

apple

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