main.cpp 范例文件

progressdialog/main.cpp
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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(); }