#include <QCoreApplication>
#include <QThread>
#include <QObject>
#include <QDebug>
// 1. 定義工作類（千萬不要繼承QThread）
class Worker : public QObject {
    Q_OBJECT
public:
    explicit Worker(int id) : m_id(id) {}
public slots:
    // 槽函數(shù)：執(zhí)行耗時任務(wù)
    void doWork() {
        qDebug() << "Worker" << m_id << "running in thread:" << QThread::currentThreadId();
        QThread::msleep(1000); // 模擬耗時操作
        int result = m_id * 100; // 模擬計算結(jié)果
        emit resultReady(m_id, result); // 發(fā)送結(jié)果信號
    }
signals:
    void resultReady(int id, int result);
private:
    int m_id;
};
int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);
    qDebug() << "Main thread:" << QThread::currentThreadId();
    QList<QThread*> threads;
    QList<Worker*> workers;
    // 創(chuàng)建 5 個工作對象和 5 個線程
    for (int i = 0; i < 5; ++i) {
        Worker *worker = new Worker(i);
        QThread *thread = new QThread();
        worker->moveToThread(thread); // 將工作對象移入新線程
        // 連接啟動信號：線程啟動后，調(diào)用 worker 的 doWork
        QObject::connect(thread, &QThread::started, worker, &Worker::doWork);
        // 連接結(jié)果信號：將結(jié)果打印到主線程
        QObject::connect(worker, &Worker::resultReady, [](int id, int result){
            qDebug() << "  -> Got result from Worker" << id << ":" << result;
        });
        // 連接清理信號：任務(wù)完成后，安全退出線程并清理內(nèi)存
        QObject::connect(worker, &Worker::resultReady, thread, &QThread::quit);
        QObject::connect(thread, &QThread::finished, worker, &QObject::deleteLater);
        QObject::connect(thread, &QThread::finished, thread, &QObject::deleteLater);
        threads.append(thread);
        workers.append(worker);
    }
    // 啟動所有線程
    for (QThread *t : threads) {
        t->start();
    }
    return a.exec();
}

#include <QCoreApplication>
#include <QThreadPool>
#include <QRunnable>
#include <QDebug>
// 1. 定義任務(wù)類
class ComputeTask : public QRunnable {
public:
    ComputeTask(int id, std::function<void(int, int)> callback) 
        : m_id(id), m_callback(callback) 
    {
        // 設(shè)置任務(wù)執(zhí)行完后自動銷毀，防止內(nèi)存泄漏
        setAutoDelete(true); 
    }
    // 重寫 run 函數(shù)
    void run() override {
        qDebug() << "Task" << m_id << "running in thread:" << QThread::currentThreadId();
        QThread::msleep(1000); // 模擬耗時操作
        int result = m_id * 100;
        // QRunnable 沒有信號槽，使用回調(diào)函數(shù)將結(jié)果傳回
        if (m_callback) {
            m_callback(m_id, result);
        }
    }
private:
    int m_id;
    std::function<void(int, int)> m_callback;
};
int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);
    qDebug() << "Main thread:" << QThread::currentThreadId();
    // 設(shè)置全局線程池最大線程數(shù)為 2（為了演示線程復(fù)用）
    QThreadPool::globalInstance()->setMaxThreadCount(2);
    for (int i = 0; i < 5; ++i) {
        // 定義回調(diào)函數(shù)接收結(jié)果
        auto callback = [](int id, int result) {
            qDebug() << "  -> Got result from Task" << id << ":" << result;
        };
        ComputeTask *task = new ComputeTask(i, callback);
        // 丟給線程池執(zhí)行
        QThreadPool::globalInstance()->start(task);
    }
    // 等待所有任務(wù)完成再退出（僅為了演示，實際GUI程序不推薦主線程wait）
    QThreadPool::globalInstance()->waitForDone();
    qDebug() << "All tasks finished.";
    return 0; // 不需要 a.exec()，因為沒有事件循環(huán)
}

#include <QCoreApplication>
#include <QtConcurrent>
#include <QFutureWatcher>
#include <QDebug>
int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);
    qDebug() << "Main thread:" << QThread::currentThreadId();
    // 同樣限制全局線程池大小以便觀察
    QThreadPool::globalInstance()->setMaxThreadCount(2);
    // 使用 QFutureWatcher 監(jiān)聽異步結(jié)果（因為 QtConcurrent 本身是非阻塞的）
    QFutureWatcher<int> *watcher = new QFutureWatcher<int>();
    // 當單個結(jié)果就緒時觸發(fā)
    QObject::connect(watcher, &QFutureWatcher<int>::resultReadyAt, [](int index) {
        qDebug() << "  -> Result at index" << index << "is ready.";
    });
    // 當所有任務(wù)完成時觸發(fā)
    QObject::connect(watcher, &QFutureWatcher<int>::finished, [watcher]() {
        qDebug() << "All concurrent tasks finished.";
        // 獲取所有結(jié)果
        QFuture<int> future = watcher->future();
        for (int i = 0; i < future.resultCount(); ++i) {
            qDebug() << "    Final Result[" << i << "] =" << future.resultAt(i);
        }
        watcher->deleteLater();
        QCoreApplication::quit(); // 退出程序
    });
    // 使用 QtConcurrent::run 啟動并發(fā)任務(wù)
    // 返回 QFuture 對象用于跟蹤狀態(tài)
    QFuture<int> future = QtConcurrent::mapped(QList<int>() << 0 << 1 << 2 << 3 << 4, [](int id) -> int {
        qDebug() << "Concurrent task" << id << "running in thread:" << QThread::currentThreadId();
        QThread::msleep(1000); // 模擬耗時
        return id * 100;       // 直接返回結(jié)果
    });
    // 將 future 交給 watcher 監(jiān)控
    watcher->setFuture(future);
    return a.exec();
}