交换方法

#import <objc/runtime.h>
// 利用runtime来替换展现弹出框的方法
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Method presentM = class_getInstanceMethod(self.class, @selector(presentViewController:animated:completion:));
        Method presentSwizzlingM = class_getInstanceMethod(self.class, @selector(ox_presentViewController:animated:completion:));
        // 交换方法实现
        method_exchangeImplementations(presentM, presentSwizzlingM);
    });

// 自己的替换展示弹出框的方法
- (void)ox_presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion {

    if ([viewControllerToPresent isKindOfClass:[UIAlertController class]]) {// 要弹出的是UIAlertController
        // 输出到控制到可以发现两者都是null
        NSLog(@"title : %@",((UIAlertController *)viewControllerToPresent).title);
        NSLog(@"message : %@",((UIAlertController *)viewControllerToPresent).message);

        // 换图标时的提示框的title和message都是nil，由此可特殊处理
        UIAlertController *alertController = (UIAlertController *)viewControllerToPresent;
        if (alertController.title == nil && alertController.message == nil) {// 是换图标的提示
            return;
        } else {// 其他提示还是正常处理
            [self ox_presentViewController:viewControllerToPresent animated:flag completion:completion];
            return;
        }
    }

    // 其他的弹出还是正常处理
    [self ox_presentViewController:viewControllerToPresent animated:flag completion:completion];
}