Xhacker Liu扩展转换为Swift 3:

extension UIButton {
    func setTitleWithoutAnimation(title: String?) {
        UIView.setAnimationsEnabled(false)

        setTitle(title, for: .normal)

        layoutIfNeeded()
        UIView.setAnimationsEnabled(true)
    }
}

Swift 4版Xhacker刘回答

import Foundation
import UIKit
extension UIButton {
    func setTitleWithOutAnimation(title: String?) {
        UIView.setAnimationsEnabled(false)

        setTitle(title, for: .normal)

        layoutIfNeeded()
        UIView.setAnimationsEnabled(true)
    }
} 

具有系统类型的UIButton在setTitle(_:for:)上有隐式动画。你可以用两种方法来解决这个问题:

设置按钮类型为自定义，从代码或接口生成器:

let button = UIButton(type: .custom)

从代码中禁用动画:

UIView.performWithoutAnimation {
    button.setTitle(title, for: .normal)
    button.layoutIfNeeded()
}

这适用于自定义按钮:

[UIView setAnimationsEnabled:NO];
[_button setTitle:@"title" forState:UIControlStateNormal];
[UIView setAnimationsEnabled:YES];

对于系统按钮，你需要在重新启用动画之前添加这个(谢谢@Klaas):

[_button layoutIfNeeded];

所以我找到了可行的解决方案:

_logoutButton.titleLabel.text = NSLocalizedString(@"Logout",);
[_logoutButton setTitle:_logoutButton.titleLabel.text forState:UIControlStateNormal];

首先我们改变按钮的标题，然后调整这个标题的按钮大小

一个方便的扩展动画按钮标题变化在Swift，发挥与默认实现很好:

import UIKit

extension UIButton {
  /// By default iOS animated the title change, which is not desirable in reusable views
  func setTitle(_ title: String?, for controlState: UIControlState, animated: Bool = true) {
    if animated {
      setTitle(title, for: controlState)
    } else {
      UIView.setAnimationsEnabled(false)
      setTitle(title, for: controlState)
      layoutIfNeeded()
      UIView.setAnimationsEnabled(true)
    }
  }
}