在非UI线程中更改UI，Delphi使用隐藏窗口来处理，QT使用信号槽
在Delphi里我记得是使用TThread.Synchronize(TThreadMethod)，原理是利用了一个隐藏窗口来处理。
在QT Debug模式一下，碰到了同样的问题，显示错误：
cannot send events to objects owned by a different thread
解决方案是使用信号槽，就是在线程里不断的发信号，UI线程的槽函数不断的接受信号并做处理：
So as a solution I would propose the following:
- Define a signal in your PaintThread class
- connect this signal to the paint() slot in QWidget subclass
- Emit it in the run() function
参考：http://stackoverflow.com/questions/9018434/qthread-doesnt-work-well
或者使用：
int ThreadTest::showProgress(int percent, void *pContext)
{
// instead of: someOtherQObject->updateProgress(percent);
QMetaObject::invokeMethod(someOtherQObject, // obj
SLOT(updateProgress(int)), // member
Qt::QueuedConnection, // connection type
Q_ARG(int, percent)); // val1
//qDebug() << "Progress: " << QString::number(percent);
return 0;
}
https://forum.qt.io/topic/9119/solved-how-can-i-evade-the-error-cannot-send-events-to-objects-owned-by-a-different-thread/4