runtime -- 方法交换的坑自定义方法不执行

今天在群里看到有人说在viewWillAppear方法里添加埋点的问题

为了降低代码耦合度，我就觉得可以用runtime的方法交换来实现

controller里的代码

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    NSLog(@"2222222222222");
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


@end

 category里的代码

#import "UIViewController+NewApear.h"
#import <objc/message.h>

@implementation UIViewController (NewApear)



-(void)newAppear:(BOOL)animated{


    
    [self newAppear:animated];
    
    NSLog(@"my code");

}

+(void)load{
    //交换方法
    
    NSLog(@"333");

    SEL originalSelector = @selector(viewWillAppear:);
    SEL swizzledSelector = @selector(newAppear:);
    
    Class class = [self class];
    Method originalMethod = class_getInstanceMethod(class, originalSelector);
    Method swizzledMethod = class_getInstanceMethod(class, swizzledSelector);
    
    BOOL didAddMethod =
    class_addMethod(class,
                    originalSelector,
                    method_getImplementation(swizzledMethod),
                    method_getTypeEncoding(swizzledMethod));
    
    if (didAddMethod) {
        class_replaceMethod(class,
                            swizzledSelector,
                            method_getImplementation(originalMethod),
                            method_getTypeEncoding(originalMethod));
    } else {
        method_exchangeImplementations(originalMethod, swizzledMethod);
    }
}

@end

 

 

这里的代码是没问题的，但是我刚开始写demo的时候，在使用viewWillAppear的时候没有写

[super viewWillAppear:animated];

导致自定义的方法不执行，所以这个super一定要调用