iOS - UIButton 作为 UIAlertController 上的 subview 未触发事件

Question

我在 UIAlertController 上添加了 UIButton，但它没有在任何事件上触发该方法。

UIButton *cancelBtn = [UIButton buttonWithType:UIButtonTypeCustom];
[cancelBtn setFrame:CGRectMake((_alertController.view.frame.size.width/2)-30, _alertController.view.frame.size.height-50, 60, 30)];
[cancelBtn setTitle:@"Cancel" forState:UIControlStateNormal];
[cancelBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
[cancelBtn setBackgroundColor:[UIColor orangeColor]];
[cancelBtn addTarget:self action:@selector(forceFullDismiss_FireDelegate:) forControlEvents:UIControlEventTouchUpInside];
cancelBtn.showsTouchWhenHighlighted = YES;

[_alertController.view setUserInteractionEnabled:YES];
[_alertController.view addSubview:cancelBtn];

按钮似乎突出显示，但相应的事件未触发。

这里有什么问题？

Answer 1

这来自 UIAlertController documentation .

The UIAlertController class is intended to be used as-is and does not support subclassing. The view hierarchy for this class is private and must not be modified.

如果要添加取消按钮，可以使用

UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
    //  action on cancel
}];

[_alertController addAction:cancel];