NSObject Swizzing

OCExt-NSObject.m

#pragma mark - Swizzling

#import <objc/runtime.h>

@interface NSObject (LWSwizzling)

+ (BOOL)swizzleMethod:(SEL)origSel withMethod:(SEL)altSel ;

+ (BOOL)swizzleClassMethod:(SEL)origSel withMethod:(SEL)altSel;

@end


@implementation NSObject (LWSwizzling)

+ (BOOL)swizzleMethod:(SEL)origSel withMethod:(SEL)altSel {
    Method origMethod = class_getInstanceMethod(self, origSel);
    Method altMethod = class_getInstanceMethod(self, altSel);
    if (!origMethod || !altMethod) {
        return NO;
    }
    class_addMethod(self,origSel,class_getMethodImplementation(self, origSel),method_getTypeEncoding(origMethod));
    class_addMethod(self,altSel,class_getMethodImplementation(self, altSel),method_getTypeEncoding(altMethod));
    method_exchangeImplementations(class_getInstanceMethod(self, origSel),class_getInstanceMethod(self, altSel));
    return YES;
}

+ (BOOL)swizzleClassMethod:(SEL)origSel withMethod:(SEL)altSel {
    return [object_getClass((id)self) swizzleMethod:origSel withMethod:altSel];
}

@end


//调用

@implementation UINavigationController (Ext)

+ (void)load {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        [self swizzleMethod:@selector(pushViewController:animated:) withMethod:@selector(myPushViewController:animated:)];
    });
}

- (void)myPushViewController:(UIViewController *)myPushViewController animated:(BOOL)animated {
    if(![self.topViewController isKindOfClass:[myPushViewController class]]){
        [self myPushViewController:myPushViewController animated:animated];
    }
}

@end