Explanations: I'm trying to create a daemon-script that will be watching the Watch folder and if I drop some files there - it should run the script.
Problem: sometimes after I drop the file - nothing happens
Script: the script is working with files in the Watch folder and deletes them after.
Additional question: do I have to delete mc object manually or it will be done automatically?
main.cpp
#include "widget.h"
#include <QFileSystemWatcher>
#include <QApplication>
#include <QDebug>
#include "myclass.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QFileSystemWatcher watcher;
watcher.addPath("/home/user/Documents/Watch/");
MyClass* mc = new MyClass;
QObject::connect(&watcher, SIGNAL(directoryChanged(QString)), mc, SLOT(showModified(QString)));
return app.exec();
}
myclass.h
#ifndef MYCLASS
#define MYCLASS
#include <QWidget>
#include <QDir>
#include <QDebug>
#include <QProcess>
class MyClass : public QWidget
{
Q_OBJECT
public:
MyClass(QWidget* parent=0)
:QWidget(parent){}
~MyClass(){}
public slots:
void showModified(const QString& str)
{
if(QDir("/home/user/Documents/Watch/").entryInfoList(QDir::NoDotAndDotDot|QDir::AllEntries).count() == 0)
{
qDebug()<<"EEEMPTYYYY!!!!!!!!!!!!!!!!!!!\n";
_status = false;
}
Q_UNUSED(str)
if (_status == false)
{
_status = true;
QProcess *proc = new QProcess();
proc->setWorkingDirectory("/home/user/Documents/");
proc->startDetached("/home/user/Documents/script.sh");
proc->waitForFinished();
delete proc;
}
}
private:
bool _status = false;
};
#endif // MYCLASS
Related
I'm trying to learn c++ so, I try to implement the observer patterns from the book Game Progamming Patterns but I'm always getting Segmentation Fault.
Searching arround I saw that Segmentation fault happens when a program try to access a non allocated memory. So I tried hard to fix it, but I can't. Someone can help me?
Here is my code:
Observer.h
#ifndef OBSERVER_H
#define OBSERVER_H
#include "EntityAndEvent.h"
#include "Subjects.h"
class Observer
{
private:
Observer* next_;
public:
Observer()
: next_(nullptr)
{}
virtual void onNotify(const Entity& entity, Event::Type event) = 0;
// Other stuff...
friend class Subjects;
};
#endif
Achievements.cpp
#ifndef ACHIEVEMENTS_CPP
#define ACHIEVEMENTS_CPP
#include "Observer.h"
#include <vector>
class Achievements : public Observer
{
public:
enum Type{
FELL_OFF,
AWAKE_ON
};
private:
std::vector<Type> done{};
public:
virtual void onNotify(const Entity&, Event::Type);
void unlock(Achievements::Type);
void printDone();
};
void Achievements::onNotify(const Entity& entity, const Event::Type event)
{
switch (event)
{
case Event::Type::ENTITY_FELL:
if(entity.isHero())
unlock(Achievements::Type::FELL_OFF);
break;
case Event::Type::ENTITY_AWAKE:
if(entity.isHero())
unlock(Achievements::Type::AWAKE_ON);
break;
default:
break;
}
};
void Achievements::unlock(Achievements::Type achiev)
{
done.push_back(achiev);
}
void Achievements::printDone()
{
// assert(done.size());
for(size_t i{0}; i < done.size(); i++)
{
std::cout << done[i] << "\n";
}
};
EntityAndEvent.cpp (i create this just to work with observer and subjects)
#ifndef ENTITY_AND_EVENT_H
#define ENTITY_AND_EVENT_H
class Entity
{
public:
inline const bool isHero() const {return true;}
};
class Event
{
public:
enum Type{
ENTITY_FELL,
ENTITY_AWAKE
};
};
#endif
Subjects.h
#ifndef SUBJECT_H
#define SUBJECT_H
#include "Observer.h"
#include <vector>
class Observer;
class Subjects
{
private:
// when implements this, prefer to use linked list or another optimized algorithms
Observer* head_{};
protected:
void notify(const Entity& Entity, Event::Type event);
public:
Subjects() : head_(NULL)
{};
~Subjects() {}
void addObserver(Observer* observer);
// const int getNumObs() const {return num_obs_;}
};
#endif
Subjects.cpp
#include "Subjects.h"
#include <cassert>
void Subjects::notify(const Entity& entity, Event::Type event)
{
Observer* observer = head_;
while (observer != NULL)
{
observer->onNotify(entity, event);
observer = observer->next_;
};
};
void Subjects::addObserver(Observer* observer)
{
if (head_ != nullptr)
observer->next_ = head_;
head_ = observer;
};
Physics.cpp (i create this just to populates the subject)
#ifndef PHYSICS_H
#define PHYSICS_H
#include "Subjects.h"
#include "EntityAndEvent.h"
class Physics: public Subjects
{
private:
public:
void update(const Entity& entity)
{
if (entity.isHero())
{
notify(entity, Event::Type::ENTITY_AWAKE);
};
};
};
#endif
main.cpp
#include "Observer.h"
#include "Achievements.h"
#include "Achievements.cpp"
#include "EntityAndEvent.h"
#include "Physics.h"
#include "Subjects.h"
#include "Subjects.cpp"
int main()
{
Physics *p{};
Entity e{};
Achievements *achiev{};
p->addObserver(achiev);
p->update(e);
return 0;
}
With Physics *p{}; you are declaring a pointer, but it currently does not point to a valid object (it is being initialized as nullptr here). Therefore, calling p->addObserver results in a segmentation fault. You should be able to confirm this by running the program in a debugger.
Why are you using a pointer here? Change Physics *p{}; to Physics p{};.
Disclaimer: Since your code is definitely not a minimum example I didn't look into the whole code or even tried to compile it. I'm only posting an answer because there is a clear error in the main function (use of an invalid pointer) that results in a segmentation fault.
first, tks for the reply. #darcamo that works. I dont know why it was declared as pointer.
I fixed that, so if anyone else have the same doubt check below:
main.cpp
#include "Observer.h"
#include "Achievements.h"
#include "EntityAndEvent.h"
#include "Physics.h"
#include "Subjects.h"
int main()
{
Physics p{};
Entity e{};
Achievements achiev{};
Observer* ptr_achiev{&achiev};
p.addObserver(ptr_achiev);
p.update(e);
return 0;
}
For an exercise i need to build a vector of polymorphic objects and for some reason both shared and Unique ptr make linkage errors 2019 and 1120 when i use them. i have no option to use the old way of memory allocation with New and Delete so i have to make it work. i tried various of different syntax options for doing this and still with no luck.
*note:
we use Cmake to bind the project together in visual studio
and also we splitting the objects into header and cpp files.
here are my objects for now:
//This is the abstract base class
#pragma once
#include <string>
class Shape
{
public:
Shape() = default;
virtual ~Shape() = default;
virtual std::string get_name() = 0;
private:
};
These are the derived classes:
#pragma once
#include "Shape.h"
class Circle : public Shape
{
public:
Circle();
~Circle();
virtual std::string get_name() override;
private:
std::string m_name;
};
Cpp file:
#pragma once
#include "Circle.h"
Circle::Circle()
: m_name("Circle")
{
}
Circle::~Circle()
{
}
std::string Circle::get_name() override
{
return m_name;
}
another derived class:
#pragma once
#include "Shape.h"
class Rectangle : public Shape
{
public:
Rectangle();
~Rectangle();
virtual std::string get_name() override;
private:
std::string m_name;
};
Cpp file:
#pragma once
#include "Rectangle.h"
Rectangle::Rectangle()
: m_name ("Rectangle")
{
}
Rectangle::~Rectangle()
{
}
std::string Rectangle::get_name() override
{
return m_name;
}
this is the class that operates the program:
#pragma once
#include <iostream>
#include <string>
#include <vector>
#include <memory>
#include "Shape.h"
#include "Circle.h"
#include "Rectangle.h"
class Board
{
public:
Board();
~Board();
void run();
void objects_allocation();
private:
std::string m_string;
std::vector<std::shared_ptr<Shape>> m_gates;
};
Cpp file:
#pragma once
#include "Board.h"
Board::Board()
: m_string(" ")
{
}
Board::~Board()
{
}
void run()
{
while (m_string != "exit")
{
std::cin >> m_string;
}
std::cout << "Goodbye!" << std::endl;
}
void Board::Objects_allocation()
{
m_gates.push_back(std::make_shared <Circle>());
m_gates.push_back(std::make_shared <Rectangle>());
}
and here is my main function:
#pragma once
#include "Board.h"
int main()
{
Board board1;
board1.run();
return 0;
}
sincerely thank you if you could explain to me what went wrong here..
The Problem was in the Cmake file. now everything is working just like i wanted.
I want to use transient scrollbar (Transient scroll bars appear when the content is scrolled and disappear when they are no longer needed) in Qt application. For this purpose I have inheritanced class QproxyStyle and reimplemented function styleHint. Code placed below.
File ScrollBar.h:
#include <QStyle>
#include <QCommonStyle>
#include <QProxyStyle>
class ScrollBarStyle : public QProxyStyle
{
public:
int styleHint(StyleHint sh, const QStyleOption *opt, const QWidget *widget, QStyleHintReturn *hret) const;
};
File ScrollBar.c:
#include "ScrollBar.h"
int ScrollBarStyle::styleHint(StyleHint sh, const QStyleOption *opt, const QWidget *widget,QStyleHintReturn *hret) const
{
int ret = 0;
switch (sh) {
case SH_ScrollBar_Transient:
ret = true;
break;
default:
return QProxyStyle::styleHint(sh, opt, widget, hret);
}
return ret;
}
File MainWindow.h:
#include <QMainWindow>
#include <QTextEdit>
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
};
File MainWindow.cpp:
#include <QTextEdit>
#include "MainWindow.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
QTextEdit *l = new (std::nothrow) QTextEdit(this);
if (l == 0)
return;
setCentralWidget(l);
}
MainWindow::~MainWindow()
{
}
File main.cpp:
#include "ScrollBar.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
ScrollBarStyle *style = new (std::nothrow) ScrollBarStyle;
if(style == 0)
return -1;
style->setBaseStyle(a.style());
w.show();
return a.exec();
}
But I have got a problem: transient scrollbar has been appearing only once (when text doesn't fit in the text area) then it has been disappeared and never come back visible.
So how can I fix this problem?
Thanks!
You have forgotten to set the style to application.
a.setStyle(style);
After I upload a file, I am trying to print out its spoolFileName() but although the application runs smoothly it seems as if the string of the name is empty. Any idea where it is wrong? (It's not the size of the file, it's less than 50k)
#include <Wt/WApplication>
#include <Wt/WFileUpload>
#include <Wt/WProgressBar>
#include <Wt/WBreak>
#include <Wt/WContainerWidget>
#include <Wt/WLineEdit>
#include <Wt/WPushButton>
#include <Wt/WText>
#include <Wt/Http/Request>
#include <Wt/WString>
using namespace Wt;
class HelloApplication: public WApplication {
public:
HelloApplication(const WEnvironment& env);
private:
WPushButton *uploadButton;
Wt::WFileUpload *fu;
Wt::WString g;
void greet();
void fileUploaded();
};
HelloApplication::HelloApplication(const WEnvironment& env) :
WApplication(env) {
root()->addStyleClass("container");
setTitle("Hello world"); // application title
fu = new Wt::WFileUpload(root());
fu->setFileTextSize(50); // Set the maximum file size to 50 kB.
fu->setProgressBar(new Wt::WProgressBar());
fu->setMargin(10, Wt::Right);
// Provide a button to start uploading.
uploadButton = new Wt::WPushButton("Send", root());
uploadButton->setMargin(10, Wt::Left | Wt::Right);
// Upload when the button is clicked.
uploadButton->clicked().connect(this, &HelloApplication::greet);
}
void HelloApplication::greet() {
fu->upload();
uploadButton->disable();
fu->uploaded().connect(this, &HelloApplication::fileUploaded);
g = fu->spoolFileName();
}
void HelloApplication::fileUploaded(){ // application title
root()->addWidget(new WText(g.value()));
}
WApplication *createApplication(const WEnvironment& env) {
return new HelloApplication(env);
}
int main(int argc, char **argv) {
return WRun(argc, argv, &createApplication);
}
I think the filename for the spool file is only known after the file is uploaded. Move
g = fu->spoolFileName();
to HelloApplication::fileUploaded().
I have 2 different QMainWindow, the first is the parent of the second. I want press some keys in the children windows and propagate the event in the parent. I create for everyone the function void keyPressEvent(QKeyEvent* event); but when i press key on the children the event is not propagate to the parent. Why?
This is the code...
//Parent class.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QKeyEvent>
#include "test.h"
#include <QDebug>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
protected:
void keyPressEvent(QKeyEvent* event);
private:
Ui::MainWindow *ui;
test *form;
private slots:
void on_pushButton_clicked();
};
#endif // MAINWINDOW_H
//Parent class.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
form = new test(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::keyPressEvent(QKeyEvent* event)
{
qDebug() << event->text();
}
void MainWindow::on_pushButton_clicked()
{
form->show();
}
//Children class.h
#ifndef TEST_H
#define TEST_H
#include <QMainWindow>
#include <QKeyEvent>
namespace Ui {
class test;
}
class test : public QMainWindow
{
Q_OBJECT
public:
explicit test(QWidget *parent = 0);
~test();
protected:
void keyPressEvent(QKeyEvent* event);
private:
Ui::test *ui;
};
#endif // TEST_H
//Children class.cpp
#include "test.h"
#include "ui_test.h"
test::test(QWidget *parent) : QMainWindow(parent), ui(new Ui::test)
{
ui->setupUi(this);
}
test::~test()
{
delete ui;
}
void test::keyPressEvent(QKeyEvent* event)
{
qDebug() << event->text();
event->ignore();
}
A QMainWindow is a top-level window and that is usually where event propagation ends. I'm not entirely clear what may be the rule though when a top-level window is parented. By your results, I'll have to assume that it stands.
In any case, you should be able to get the event by defining a filter method in your MainWindow class and installing it on test class. Refer to this documentation.
You also have the option of overriding the event() method of QApplication.