qt - Qt:事件是否按顺序处理？

Question

如果我有A类，那么它的功能之一是:

void A::func()
{
    emit first_signal();
    emit second_signal();
}

假设B类有2个插槽，一个插槽连接到first_signal，另一个插槽连接到second_signal，是否可以保证在到first_signal插槽之前，始终处理来处理连接到second_signal的插槽？

Answer 1

如果在信号和插槽之间使用直接连接类型(Qt::DirectConnection)，则答案是肯定的。

从Qt帮助系统:

When a signal is emitted, the slots connected to it are usually executed immediately, just like a normal function call. When this happens, the signals and slots mechanism is totally independent of any GUI event loop. Execution of the code following the emit statement will occur once all slots have returned. The situation is slightly different when using queued connections; in such a case, the code following the emit keyword will continue immediately, and the slots will be executed later.

您可以使用enum Qt::ConnectionType方法将默认连接类型更改为QObject::connect中的任何一种。