Runtime系列（Method Swizzzling）

最新推荐文章于 2023-10-13 07:45:00 发布

原创最新推荐文章于 2023-10-13 07:45:00 发布 · 379 阅读

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如何为一个实例动态替换方法？

#import "ViewController.h"
#import <objc/runtime.h>
@interface ViewController ()

@end

@implementation ViewController

+(void)load {
    static dispatch_once_t onceToken;  //必须只调用一次，如果调用偶数次，就会起不到交换的作用
    dispatch_once(&onceToken,^{
        SEL originSel = @selector(originFunc);
        SEL swizzlingSel = @selector(swizzlingFunc);
        
        Method originMethod = class_getInstanceMethod(self,originSel);
        Method swizzlingMethod = class_getInstanceMethod(self, swizzlingSel);
        
        BOOL methodAdded = class_addMethod(self, originSel, method_getImplementation(swizzlingMethod), method_getTypeEncoding(swizzlingMethod));
        if(methodAdded) {
            class_replaceMethod(self, swizzlingSel, method_getImplementation(originMethod), method_getTypeEncoding(originMethod));  
        } else{
            method_exchangeImplementations(originMethod, swizzlingMethod);
        }
        
    });
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self originFunc];
}

-(void)originFunc {
    NSLog(@"%s",__func__);
}

-(void)swizzlingFunc {
    NSLog(@"%s",__func__);
}


@end

2017-03-24 21:50:37.911 ceshi3[8508:83721] -[ViewController swizzlingFunc]