QFurture是異步進行的，可以開1個或多個線程。返回值可以是任意類型的。當調用result(),?resultAt(),?results()返回值無效時QFuture將會等待result返回正常為止。可以使用isResultReadAt()函數(shù)去判斷是否有數(shù)據。QFuture返回值可以是多個，使用resultCount()函數(shù)可以得到其數(shù)量。

還有很多函數(shù)就不一一介紹了。直接在代碼中演示吧！

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下面是一個官方例子：

runfunction.pro

QT += concurrent widgets CONFIG += cmdlineSOURCES += main.cpptarget.path = $$[QT_INSTALL_EXAMPLES]/qtconcurrent/runfunction INSTALLS += target

main.cpp

#include <QDebug> #include <QThread> #include <QString> #include <qtconcurrentrun.h> #include <QApplication>using namespace QtConcurrent;void hello(QString name) {qDebug() << "Hello" << name << "from" << QThread::currentThread(); }int main(int argc, char **argv) {QApplication app(argc, argv);QFuture<void> f1 = run(hello, QString("Alice"));QFuture<void> f2 = run(hello, QString("Bob"));f1.waitForFinished();f2.waitForFinished(); }

程序運行截圖如下：

下面是處理大量數(shù)據的例子：

源碼如下：

FutureDemo.pro

QT -= gui QT += concurrentCONFIG += c++11 console CONFIG -= app_bundle# The following define makes your compiler emit warnings if you use # any Qt feature that has been marked deprecated (the exact warnings # depend on your compiler). Please consult the documentation of the # deprecated API in order to know how to port your code away from it. DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if it uses deprecated APIs. # In order to do so, uncomment the following line. # You can also select to disable deprecated APIs only up to a certain version of Qt. #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0SOURCES += \main.cpp# Default rules for deployment. qnx: target.path = /tmp/$${TARGET}/bin else: unix:!android: target.path = /opt/$${TARGET}/bin !isEmpty(target.path): INSTALLS += target

main.cpp

#include <QCoreApplication> #include <QtConcurrent> #include <QTimer> #include <QTime> #include <QEventLoop> #include <QVector> #include <QMapIterator> #include <QString> #include <QDebug> #include <QMap>using namespace QtConcurrent;QVector<int> MyTest(QVector<int> vec){qDebug() << "deal with vec ! " << QThread::currentThread();QVector<int> ret;for(int i = 0; i < vec.size(); i++){ret << vec[i] - vec[i];}qDebug() << "deal with vec ! finished" << QThread::currentThread();return ret; }int main(int argc, char *argv[]) {QCoreApplication a(argc, argv);qsrand(QTime(0, 0, 0).secsTo(QTime::currentTime()));QVector<int> oriData;for(int i = 0; i < 1000000; i++){oriData.append(qrand() % 50000);}qDebug() << "隨機數(shù)生成完成！";QVector<int> overData;QList<QFuture<QVector<int>>> list;for(int i = 0; i < 1000000; i+= 10000){QFuture<QVector<int>> future = run(MyTest, oriData.mid(i, 10000));list.append(future);}QEventLoop loop;QTimer::singleShot(2 * 1000, &loop, &QEventLoop::quit);loop.exec();for(int i = 0; i < list.size(); i++){list[i].waitForFinished();overData.append(list[i]);}qDebug() << "over";return a.exec(); }

運行截圖如下：

變量

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