请注意:

当_button的"buttonType"为"UIButtonTypeSystem"时，以下代码无效:

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

当_button的"buttonType"为"UIButtonTypeCustom"时，上述代码有效。

在Swift中，你可以使用:

UIView.performWithoutAnimation {
    self.someButtonButton.setTitle(newTitle, forState: .normal)
    self.someButtonButton.layoutIfNeeded()
}

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)
    }
} 

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)
    }
}

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

斯威夫特5

myButton.titleLabel?.text = "title"
myButton.setTitle("title", for: .normal)