利用runtime的特性，创建一个UIViewController的分类，然后pch文件导入
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface UIViewController (PModel)
@end
NS_ASSUME_NONNULL_END
#import "UIViewController+PModel.h"
#import <objc/runtime.h>
@implementation UIViewController (PModel)
+(void)load{
Method m1 = class_getInstanceMethod([self class], @selector(presentViewController:animated:completion:));
Method m2 = class_getInstanceMethod([self class], @selector(p_presentViewController:animated:completion:));
method_exchangeImplementations(m1, m2);
}
- (void)p_presentViewController:(UIViewController *)viewControllerToPresent animated: (BOOL)flag completion:(void (^ __nullable)(void))completion{
viewControllerToPresent.modalPresentationStyle = UIModalPresentationFullScreen;
[self p_presentViewController:viewControllerToPresent animated:flag completion:completion];
}
@end
