How to capture a variable's current value for a block

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無奈伤痛
無奈伤痛 2021-01-21 12:17

Is there a way to save the current value of a varible for later usage in a block?

For example, for this Playground code:

import UIKit
import XCPlayground         


        
2条回答
  •  离开以前
    2021-01-21 13:21

    Since you're referencing i through a captured self, you will get whatever the value is at dispatch time. If you want to capture the value as it is at the beginning of the function, you'll need to get a local copy before changing it.

        let x = self.i
        dispatch_after(dispatchTime, dispatch_get_main_queue(), {
            self.test(x)
        })
    

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