removed sleep, delay no longer blocks event loop

window.cpp

@@ -9,6 +9,7 @@
 #include <QHBoxLayout>
 #include <QVBoxLayout>
 #include <QSpacerItem>
+#include <QTimer>
 
 Window::Window(QWidget *parent)
     : QWidget{parent}
@@ -85,7 +86,7 @@ void Window::solveButtonClicked()
     while (1)
     {
         repaint(); // draw cells again
-        QThread::msleep(m_delay);
+        delay(m_delay);
         if (backtracking)
         {
             hist.back()->cell->un();
@@ -97,7 +98,7 @@ void Window::solveButtonClicked()
             backtracking = false;
             int choiceNr = rand() % hist.back()->index.size(); // choose a random number;
             repaint();                                         // draw cells again
-            QThread::msleep(m_delay);
+            delay(m_delay);
             hist.back()->cell->collapse(hist.back()->index[choiceNr]); // collapse cell with chosen number;
             std::vector<int>::iterator it;
             it = hist.back()->index.begin() + choiceNr;
@@ -145,7 +146,14 @@ void Window::solveButtonClicked()
     }
     // qInfo("%d---:)");
 }
-
+inline void Window::delay(int millisecondsWait)
+{
+    QEventLoop loop;
+    QTimer t;
+    t.connect(&t, &QTimer::timeout, &loop, &QEventLoop::quit);
+    t.start(millisecondsWait);
+    loop.exec();
+}
 void Window::clearButtonClicked()
 {
     for (auto &x : m_cell)

window.h

@@ -35,6 +35,7 @@ private:
             }
         }
     };
+    inline void delay(int millisecondsWait);
 
 signals:
     void counterReached();