QFutureWatcher没有调用连接的插槽

Question

我有以下代码实现QtConcurrent::run()与QFutureWatcher启动fetch()运行shell进程的函数.完成后,我想调用该writeDesc函数,但它永远不会被调用.

void MyClass::on_fetchButton_clicked()
{
    QFuture<void> fetcher;
    QFutureWatcher<void> watcher;
    connect(&watcher, SIGNAL(finished()), this, SLOT(writeDesc()));
    fetcher = QtConcurrent::run(this, &MyClass::fetch);
    watcher.setFuture(fetcher);
}

void MyClass::fetch()
{
    [...]
    qDebug()<<"Thread done";
}

void MyClass::writeDesc()
{
    qDebug()<<"Slot called";
    [...]
}

fetch()工作正常,但程序只显示调试消息,Thread done而不是Slot called.为什么不writeDesc被召唤？

Answer 1

问题是观察者对象在离开MyClass::on_fetchButton_clicked()方法时被破坏.被破坏的物体不能发射物体.尝试在类的构造函数中分配和连接观察程序.不要忘记在析构函数中销毁.