QFileSystemWatcher不会在控制台应用程序中发出fileChanged()
在我的文件sole.h/..cpp中，我有一个小类，它只要求用户输入一些文本，然后再打印文本，直到用户输入“退出”(参见方法consoleMain())。但是，在main.cpp中，我也有一个QFileSystemWatcher，它监视文件MyTextFile.txt，并在文本文件更改时调用Console::slotFileChanged(QString)。不幸的是，QFileSystemWatcher无法工作。当我更改文本文件时，永远不会执行Console::slotFileChanged(QString)。据我所知，只有当主事件循环已经启动时，QFileSystemWatcher才能工作，这在我的代码中也是如此。当我在QTimer::singlaShot中禁用main.cpp并将其替换为emit console.signalStart()时，主事件循环将不会被输入，但在输入“退出”后，我会看到QFileSystemWatcher ("File！“)的消息。问题是:是否可以让用户与控制台交互，并让FileWatcher在并行更改文本文件时发出信号？(我还尝试将QFileSystemWatcher放入控制台类并在堆中创建；不幸的是，它没有改变任何东西)
这是我的代码：
控制台.h
#ifndef CONSOLE_H
#define CONSOLE_H
#include <iostream>
#include <QObject>
#include <QFileSystemWatcher>
class Console: public QObject
{
Q_OBJECT
public:
Console(QObject *parent = 0);
~Console();
signals:
void signalStart();
void signalEnd();
public slots:
void consoleMain();
void slotFileChanged(QString text);
void slotEmit();
};
#endif // CONSOLE_Hconsole.cpp
#include "console.h"
Console::Console(QObject *parent): QObject(parent)
{
}
Console::~Console()
{
}
void Console::consoleMain()
{
bool isRunning = true;
std::string in;
while (isRunning)
{
std::cout << ">" << std::flush;
std::getline(std::cin, in);
if (in.compare("quit") == 0)
isRunning = false;
else
std::cout << "You have entered: " << in << std::endl;
}
emit signalEnd();
}
void Console::slotFileChanged(QString text)
{
Q_UNUSED(text);
std::cout << "File changed!" << std::endl;
}
void Console::slotEmit()
{
emit signalStart();
}main.cpp
#include "console.h"
#include <QCoreApplication>
#include <QTimer>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QFileSystemWatcher watcher(&a);
watcher.addPath("C:/MyTextFile.txt");
Console console(&a);
QObject::connect(&console, SIGNAL(signalStart()), &console, SLOT(consoleMain()));
QObject::connect(&console, SIGNAL(signalEnd()), &a, SLOT(quit()));
QObject::connect(&watcher, SIGNAL(fileChanged(QString)), &console, SLOT(slotFileChanged(QString)));
QTimer::singleShot(0, &console, SLOT(slotEmit()));
//emit console.signalStart();
std::cout << "Enter main event loop now" << std::endl;
return a.exec();
}回答 1
Stack Overflow用户
发布于 2015-04-23 20:16:55
好了，解决了。我用不同的线程尝试了Yakk的想法(谢谢你的想法，Yakk)。我不得不引入一个名为QObject的新子类MyObject。在其构造函数中，我为控制台对象创建了Console和一个新的QThread。QFileSystemWatcher是在main.cpp以及MyObjcet的一个实例中创建的。见下面的代码：
myobject.h
#ifndef MYOBJECT_H
#define MYOBJECT_H
#include "console.h"
#include <QThread>
#include <QCoreApplication>
class MyObject : public QObject
{
Q_OBJECT
public:
MyObject(QObject *parent = 0);
~MyObject();
private:
QThread *thread;
Console *console;
signals:
void signalStart();
public slots:
void slotFileChanged(QString text);
void slotEnd();
};
#endif // MYOBJECT_Hmyobject.cpp
#include "myobject.h"
MyObject::MyObject(QObject *parent): QObject(parent)
{
console = new Console;
thread = new QThread(this);
console->moveToThread(thread);
thread->start();
connect(this, SIGNAL(signalStart()), console, SLOT(consoleMain()));
connect(console, SIGNAL(signalEnd()), this, SLOT(slotEnd()));
emit signalStart();
}
MyObject::~MyObject()
{
thread->quit();
thread->wait();
}
void MyObject::slotFileChanged(QString text)
{
console->displayChangedFileText(text);
}
void MyObject::slotEnd()
{
QCoreApplication::exit(0);
}main.cpp
#include "myobject.h"
#include <QTimer>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QFileSystemWatcher *watcher = new QFileSystemWatcher(&a);
watcher->addPath("C:/MyTextFile.txt");
MyObject *object = new MyObject(&a);
QObject::connect(watcher, SIGNAL(fileChanged(QString)), object, SLOT(slotFileChanged(QString)));
std::cout << "Enter main event loop now" << std::endl;
return a.exec();
}控制台h/..cpp不存在，只有Console::slotFileChanged(QString)被Console::displayChangedFileText(QString)所取代。
https://stackoverflow.com/questions/29807758
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