如果你只关心回来时的行程，你可以在返回前把它弄好。

If you only care about the return trip, you can set it up before you return.

youdao

在后台执行程序的时候返回给调用线程进度的参数类型。

Progress, the type of the progress units published during the background computation.

youdao

在后台执行程序的时候返回给调用线程进度的参数类型。

Progress, the type of the progress units published during the background computation.

youdao