qt5base-lts/examples/qtconcurrent/progressdialog/main.cpp
Michael Winkelmann ab9f4d5db6 Revamp QtConcurrent examples to C++11
I updated signals and slots and for each loops to the new syntax and
replaced most free functions with std::function.

Task-number: QTBUG-60641
Change-Id: I7693f81f71c7f53fcbe83189a0de2fb76ddf99a8
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
2017-11-07 09:42:34 +00:00

101 lines
4.0 KiB
C++

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#include <QtWidgets>
#include <QtConcurrent>
#include <functional>
using namespace QtConcurrent;
int main(int argc, char **argv)
{
QApplication app(argc, argv);
const int iterations = 20;
// Prepare the vector.
QVector<int> vector;
for (int i = 0; i < iterations; ++i)
vector.append(i);
// Create a progress dialog.
QProgressDialog dialog;
dialog.setLabelText(QString("Progressing using %1 thread(s)...").arg(QThread::idealThreadCount()));
// Create a QFutureWatcher and connect signals and slots.
QFutureWatcher<void> futureWatcher;
QObject::connect(&futureWatcher, &QFutureWatcher<void>::finished, &dialog, &QProgressDialog::reset);
QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher, &QFutureWatcher<void>::cancel);
QObject::connect(&futureWatcher, &QFutureWatcher<void>::progressRangeChanged, &dialog, &QProgressDialog::setRange);
QObject::connect(&futureWatcher, &QFutureWatcher<void>::progressValueChanged, &dialog, &QProgressDialog::setValue);
// Our function to compute
std::function<void(int&)> spin = [](int &iteration) {
const int work = 1000 * 1000 * 40;
volatile int v = 0;
for (int j = 0; j < work; ++j)
++v;
qDebug() << "iteration" << iteration << "in thread" << QThread::currentThreadId();
};
// Start the computation.
futureWatcher.setFuture(QtConcurrent::map(vector, spin));
// Display the dialog and start the event loop.
dialog.exec();
futureWatcher.waitForFinished();
// Query the future to check if was canceled.
qDebug() << "Canceled?" << futureWatcher.future().isCanceled();
}