“实时"更新一个Qt TextView [英] "real time" update a Qt TextView

问题描述

我有一个带有嵌入式脚本/jit的Qt应用程序.现在，我想从QTextEdit(更具体的QPlainTextEdit)上的脚本接收输出.为此，将发出回调.我面临的问题是，无论我尝试执行什么操作，TextEdit的输出要么延迟到脚本完成，要么在2-3秒后卡住(然后延迟，直到脚本完成). 我尝试使用信号和插槽进行更新，但也使用直接函数调用-均无效.同样，重新粉刷/更新TextEdit和父窗体，甚至QCoreApplication :: flush()都显示很少/没有效果.似乎我在做一些根本错误的事情.有什么想法或示例可以实现实时"更新吗?

I have a Qt application with an embedded script/jit. Now I'd like to receive the output from the script on an QTextEdit (more specific QPlainTextEdit). For this purpose callbacks are being issued. The problem I'm facing is that whatever I try the output to the TextEdit is either delayed until the script has finished or gets stuck after 2-3 seconds (and is delayed then until the script has finished). I tried to use signals and slots for the update but also direct function calls - neither worked. Also repainting / updating the TextEdit and the parent form as well as even QCoreApplication::flush() did show little/no effect. Seems like I'm doing something fundamentally wrong. Any ideas or examples how to achive the "real time" updates?

顺便说一句，正在调用更新例程-实时提供对stdout的调试输出.

Btw, the update routines are being called - debug output to stdout is avaiable in real time.

推荐答案

只是使用线程来绘制解决方案，我已经多次使用它来记录日志，并且可以按需工作:

Just to sketch a soluting using threads, which I have used numerous times for logging purposes and which works as desired:

定义您的线程类:

class MyThread : public QThread
{
  Q_OBJECT
public:
  MyThread(QObject *parent=0) : QThread(parent) {}
signals:
  void signalLogMessage(const QString &logMessage);

...
};

只要您希望在主线程中显示日志消息，只需使用

Whenever you want a log message to be shown in the main thread, just use

emit signalLogMessage("Foo!");

在您的主线程中:

MyThread *thread = new MyThread(this);
connect(thread, SIGNAL(signalLogMessage(const QString&)), 
        this, SLOT(logMessageFromThread(const QString&)));
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
...
thread->start();

其中logMessageFromThread的作用类似于myPlainTextEdit->appendPlainText(message). 这样可以正常工作，没有任何延迟或其他问题.

where logMessageFromThread does something like myPlainTextEdit->appendPlainText(message). This works without any delay or other problems.

我希望能帮上忙.

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