如何重繪另一個Qt的類

Question

我在Qt的新有點...

我有一個Qt的GUI應用程序（由我寫的），我們稱之爲QtAPP.exe 當QtAPP.exe運行，我將使用QThread和QProcess來執行一些外部文件，如player.exe（用原生C語言編寫）等 。

我的問題是： 在QtAPP.exe，有​​2個班， 1的QMainWindow - 核心QtAPP.exe的 2的QThread - 線程類執行外部事物

現在，如果我在QThread中獲得完成（）信號， 我該如何強制QMainWindow重新繪製自己？

希望有人能告訴我一些提示，也許示例代碼:) 任何建議，歡迎〜

Answer 1

一個解決辦法是簡單地完成的（）信號連接到插槽中主窗口，其實現調用update（） 。請注意，由於發送者和接收者對象位於不同的線程中，因此此信號的傳遞將是異步的。

這裏是一個工作示例：

的main.cpp

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

int main(int argc, char *argv[]) 
{ 
    QApplication app(argc, argv); 
    MainWindow w; 
    w.show(); 
    return app.exec(); 
} 

stuff.h

#ifndef STUFF_H 
#define STUFF_H 

#include <QtGui/QMainWindow> 
#include <QtCore/QThread> 

class QLabel; 

class Thread : public QThread 
{ 
    Q_OBJECT 
public: 
    Thread(QObject *parent); 
    void run(); 

private: 
    void startWork(); 

signals: 
    void workFinished(); 
}; 

class MainWindow : public QWidget 
{ 
    Q_OBJECT 
public: 
    MainWindow(); 

public slots: 
    void startWork(); 
    void workFinished(); 

private: 
    QLabel* m_label; 
    Thread* m_thread; 
}; 

#endif 

stuff.cpp

#include <QtCore/QTimer> 
#include <QtCore/QMutex> 
#include <QtCore/QWaitCondition> 
#include <QtGui/QVBoxLayout> 
#include <QtGui/QPushButton> 
#include <QtGui/QLabel> 
#include "stuff.h" 

#include <QDebug> 

// Global variables used for ITC 
QWaitCondition buttonPressed; 
QMutex mutex; 

Thread::Thread(QObject *parent) 
    : QThread(parent) 
{ 

} 

void Thread::run() 
{ 
    qDebug() << "Thread::run" << QThread::currentThreadId(); 
    while (1) { 
     mutex.lock(); 
     buttonPressed.wait(&mutex); 
     mutex.unlock(); 
     startWork(); 
    } 
} 

void Thread::startWork() 
{ 
    qDebug() << "Thread::startWork" << QThread::currentThreadId(); 
    // Simulate some long-running task 
    sleep(3); 
    // Emit a signal, which will be received in the main thread 
    emit workFinished(); 
} 


MainWindow::MainWindow() 
    : m_label(new QLabel(this)) 
    , m_thread(new Thread(this)) 
{ 
    QPushButton *button = new QPushButton("Start", this); 
    connect(button, SIGNAL(pressed()), this, SLOT(startWork())); 

    QVBoxLayout *layout = new QVBoxLayout(this); 
    layout->addWidget(button); 
    layout->addWidget(m_label); 
    setLayout(layout); 

    // Create connection across thread boundary 
    connect(m_thread, SIGNAL(workFinished()), this, SLOT(workFinished())); 

    m_thread->start(); 
} 

void MainWindow::startWork() 
{ 
    // Signal the thread to tell it that the button has been pressed 
    mutex.lock(); 
    m_label->setText("Started"); 
    buttonPressed.wakeAll(); 
    mutex.unlock(); 
} 

void MainWindow::workFinished() 
{ 
    qDebug() << "MainWindow::workFinished" << QThread::currentThreadId(); 
    m_label->setText("Finished"); 
}