Swift 闭包中循环引用解决方式

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Swift 闭包中循环引用解决方

示例说明:开启一个定时器,然后每隔一秒钟加1秒,直到60秒

变量声明

  1. //声明一个定时器变量
  2. var timer: Timer?
  3. var currentSeconds: Int = 0

weak 方式

  1. func testTimer(){
  2.  
  3. weak var weakSelf : CurrentController? = self
  4. timer = Timer.scheduledTimer(withTimeInterval: 1.0,repeats: true,block: { _ in
  5.  
  6. weakSelf?.currentSeconds += 1
  7.  
  8. if weakSelf?.currentSeconds == 60{
  9.  
  10. weakSelf?.timer?.invalidate()
  11. weakSelf?.timer = nil
  12. }
  13. })
  14. }

[weak self] 方式

  1. func testTimer(){
  2. timer = Timer.scheduledTimer(withTimeInterval: 1.0,repeats: true,block: {[weak self] (_) in
  3.  
  4. self?.currentSeconds += 1
  5.  
  6. if self?.currentSeconds == 60{
  7.  
  8. self?.timer?.invalidate()
  9. self?.timer = nil
  10. }
  11. })
  12. }

[unowned self] 方式

  1. func testTimer(){
  2.  
  3. timer = Timer.scheduledTimer(withTimeInterval: 1.0,block: {[unowned self] (_) in
  4.  
  5. self.currentSeconds += 1
  6.  
  7. if self.currentSeconds == 60{
  8. self.timer?.invalidate()
  9. self.timer = nil
  10. }
  11. })
  12. }

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