QT refresh UI interface problem

When performing the settext() After the operation , If there is a dead loop or processing that takes up a lot of main thread time , Then the interface will not be updated immediately , The interface will only be updated after the logic is processed , So what can I do to update the interface immediately ？
The first one is ： Put the operation that takes up a lot of resources of the main thread into another thread to execute , This will not affect the interface update operation of the main thread
The second kind ： perform settext() Then directly execute once qApp->processEvent() In this way, the interface can be updated immediately

It needs to be said that the update interface is waiting for execution a. exec() Before you can update , And in the a. exec() In fact, it is also processEvent() function

Ui The update of can only be in the main thread

Although the interface is updated after the logic is executed , Yes a. exec() Then the interface will be updated , But there is a special control that will update the interface immediately , That is the progress bar control QProcessBar Medium setvalue() function , This will update the interface immediately , And if the setvalue() There was an operation to update other controls , You can also update the interface immediately , Estimated progress bar setvalue() Is also implemented qApp->processEvent() To update the interface immediately