qthread

PySide2 Qthread crash

由 ╄→尐↘猪︶ㄣ 提交于 2020-01-24 17:55:12
问题 I want to use PySide2 Qtcore.Qthread because of Qtcore.Signal, but I end up with this error: Process finished with exit code -1073740791 from PySide2.QtCore import QThread class Thread(QThread): def run(self): print('task started') k = 0 for i in range(10000): for j in range(5000): k += 1 print('task finished') Thread().start() expect to have those prints but I have this error: Process finished with exit code -1073740791 Update: so, why this code also throw the same error? class Thread

Show progressbar in Qt with computationally heavy background process

由 扶醉桌前 提交于 2020-01-23 04:02:29
问题 I'm building an application that let's the user export his/her work. This is a computationally heavy process, lasting for a minute or so, during which I want to show a progress bar (and make the rest of the UI unresponsive). I've tried the implementation below, which works fine for a non-computationally expensive background process (e.g. waiting for 0.1 s). However, for a CPU heavy process, the UI becomes very laggy and unresponsive (but not completely unresponsive). Any idea how I can solve

QT多线程操作

由 家住魔仙堡 提交于 2020-01-22 13:47:38
QT的线程开启方式有俩种方法 方法一: 1.派生QThread类,重写父类的run函数.派生对象调用strat()函数; 二方法: 1.派生出一个QObject的子类,再创建一个QThread对象; 2.把需要在线程运行的函数写在QObject的子类的槽中; 3通过QObject的子类的对象moveToThread()移动到线程对象中去; 4.连接connect(线程对象,SIGNAL(strated()),QObject派生类对象,SLOT(func())); 5.线程对象调用strat()函数; 官网推荐第二种方法开启线程,这里需要注意的是一个QThread类的派生对象就是一条线程,当线程调用strat()函数,默认调用了run()函数,run函数又底层调用了exec()事件循环; 所以线程内函数运行结束了,需要回收资源的话,需要先调用quit()函数退出事件循环,再调用wait()来回收线程资源; 注:QObject派生类对象如果槽函数是死循环需要设置一个flag来终止,对象的资源回收需要线程来完成deleteLater(),不可以设置父类托管内存,因为该对象已经不在主线程中了; 示例: 新建一个窗口类,放入俩个LCD控件,一个按钮控件; widget.h 1 #ifndef WIDGET_H 2 #define WIDGET_H 3 4 #include <QWidget>

QThread blocking main application

由 匆匆过客 提交于 2020-01-20 22:14:06
问题 I have a simple form UI that has a slot for a button, starting a thread: void MainWindow::LoadImage() { aThread->run(); } And the run() method looks like this: void CameraThread::run() { qDebug("Staring Thread"); while(1) { qDebug("ping"); QThread::sleep(1); } } When I click the button that calls LoadImage(), the UI becomes unresponsive. I periodically see the "ping" message as the debug output but the UI hangs, does not respond to anything. Why is my thread not running separately?

QThread and QTimer

由 跟風遠走 提交于 2020-01-20 06:51:05
问题 I'm working on an application developed with Qt 4.6. I want to create a custom timer that counts in a separate thread. However, I want this timer to be able to send signals to the main thread. I subclassed QThread but it doesn't seem to work. Here is Timer.h: #ifndef TIMER_H #define TIMER_H #include <QtCore/QObject> #include <QtCore/QThread> #include <QtCore/QTimer> class Timer : public QThread { Q_OBJECT public: explicit Timer(QObject *parent = 0); ~Timer(); // true if the timer is active

用Python来做一个屏幕录制工具

由 谁说胖子不能爱 提交于 2020-01-18 13:58:33
一、写在前面 作为一名测试，有时候经常会遇到需要录屏记录自己操作，方便后续开发同学定位。以前都是用ScreenToGif来录屏制作成动态图，偶尔的机会看到python也能实现。那就赶紧学习下。 二、效果展示 三、知识串讲 这次要讲的东西可能比较多了，涉及到pyqt5 GUI软件的制作、QThread多线程的使用、Sikuli库的图形操作、win32库的模拟键盘操作、cv2库的写视频文件等。下面我们一点点来蚕食我这次写的代码。 1、GUI界面制作 这次我用的是现成的Pyqt5界面布局类，QVBoxLayout。这个类可以快速协助我完成按钮的垂直分布，而且按钮添加也更方便。 button1 = QPushButton("自定义录屏") layout.addWidget(button1) 两行代码就完成了按钮的命名和添加。我之前玩qt时，用的都是qt的UI界面，对应生成的组件代码也比较复杂。因此，在开发一些少量按钮、简单布局时可以用QVBoxLayout类。如果喜欢水平布局，可以用QHBoxLayout类，使用方法是一样的。 另外，在按钮点击关联的功能函数，即work()方法时，如果想带参数，可以通过lambda匿名函数来实现。这 也是个小技巧。 # 不带参数 button1.clicked.connect(self.work) # 带参数 button1.clicked.connect

QObject Cannot create children for a parent that is in a different thread

由 Deadly 提交于 2020-01-15 09:06:51
问题 Hi have need to do some socket communication from background, I used QtConcurrent::run to this, but giving me the warning. QObject: Cannot create children for a parent that is in a different thread. (Parent is MainWindow(0x7fff3e69f500), parent's thread is QThread(0x16f8070), current thread is QThread(0x17413d0) Here is the code, MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),ui(new Ui::MainWindow){ ui->setupUi(this); QFuture<void> f2 = QtConcurrent::run(this,&MainWindow:

QT多线程的使用

由 风流意气都作罢 提交于 2020-01-15 04:45:22
Qt中提供了对于线程的支持，它提供了一些独立于平台的线程类，要进行多线程方法，可以有两种方式。 1. 第一种方式 qt提供QThread类，在QThread类中有一个virtual函数QThread::run()。 要创建一个新的线程，我们只需定义一个MyThread类，让其继承QThread，然后重新实现QThread::run()。 #ifndef MYTHREAD_H #define MYTHREAD_H #include <QThread> class MyThread : public QThread { Q_OBJECT public: explicit MyThread(QObject *parent = 0); ~MyThread(); protected: //QThread的虚函数 //线程处理函数 //不能直接调用，通过start()间接调用 void run(); signals: void isDone(); //处理完成信号 signals: public slots: }; #endif // MYTHREAD_H }; 然后可以在run中写入要进行的操作，比如可以让其等待5秒。若不是多线程，在运行时我们单击窗口，窗口会出现无响应的状态。 那如何通知线程结束？这就可以用qt的信号和槽机制了，我们可以在操作完成时发出一个完成信号

creating QApplication in a different thread

由 我只是一个虾纸丫 提交于 2020-01-11 06:35:11
问题 I'm trying to create QApplication in a different thread, but found 2 main problems: 1- I can't interact with GUI 2- some warnings: WARNING: QApplication was not created in the main() thread. QObject::startTimer: timers cannot be started from another thread //happens when resizing widget QObject::killTimer: timers cannot be stopped from another thread here is the full code: (it may has some memory leaks but for testing purposes it fails) //main.cpp #include <QCoreApplication> #include "cthread

How to use QThread correctly in pyqt with moveToThread()?

由 对着背影说爱祢 提交于 2020-01-09 05:00:14
问题 i read this article How To Really, Truly Use QThreads; The Full Explanation, it says instead of subclass qthread, and reimplement run(), one should use moveToThread to push a QObject onto QThread instance using moveToThread(QThread*) here is the c++ example, but i don't know how to convert it to python code. class Worker : public QObject { Q_OBJECT QThread workerThread; public slots: void doWork(const QString &parameter) { // ... emit resultReady(result); } signals: void resultReady(const
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