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

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。

也许生成2个动画和2个按钮是一个更好的解决方案，以避免出现动画和更改按钮文本的问题?

我创建了第二个uibutton并生成了2个动画，这个解决方案没有hickup。

    _button2.hidden = TRUE;
    _button1.hidden = FALSE;

    CGPoint startLocation = CGPointMake(_button1.center.x, button1.center.y - 70);
    CGPoint stopLocation  = CGPointMake(_button2.center.x, button2.center.y- 70);


    [UIView animateWithDuration:0.3 animations:^{ _button2.center = stopLocation;} completion:^(BOOL finished){_button2.center = stopLocation;}];
    [UIView animateWithDuration:0.3 animations:^{ _button1.center = startLocation;} completion:^(BOOL finished){_button1.center = startLocation;}];

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()
}

我得到了它的工作组合的答案:

[[[button titleLabel] layer] removeAllAnimations];

    [UIView performWithoutAnimation:^{

        [button setTitle:@"Title" forState:UIControlStateNormal];

    }];

设置UIButton类型为自定义。这应该会删除淡入和淡出动画。