iOS开发 runtime实现原理以及实际开发中的应用
2024-08-27 07:57:54
自己写了一个小例子：有一些相关知识点和博客文章
A: 首先现在控制器里面初始化一个对象，然后调用对象的方法：
#import "ViewController.h"
#import "Message.h"
#import "NSObject+AssociatedObject.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
Message *message = [Message new];
[message sendMessage:@"Sam Lau"];
}
@endB: 对象First的声明：
//
// Message.h
// RuntimeDemo
//
// Created by caijunrong on 7/15/15.
// Copyright © 2015 caijunrong. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface Message : NSObject
- (void)sendMessage:(NSString *)word;
@end对象First的实现：
//
// Message.m
// RuntimeDemo
//
// Created by caijunrong on 7/15/15.
// Copyright © 2015 caijunrong. All rights reserved.
//
#import "Message.h"
#import "MessageForwarding.h"
#import <objc/runtime.h>
@implementation Message
//- (void)sendMessage:(NSString *)word
//{
// NSLog(@"normal way : send message = %@", word);
//}
//- (void)sendOtherMessage:(NSString *)word{
// NSLog(@"sendOtherMessage word:%@",word);
//}
#pragma mark - Method Resolution
/// override resolveInstanceMethod or resolveClassMethod for changing sendMessage method implementation
+ (BOOL)resolveInstanceMethod:(SEL)sel
{
if (sel == @selector(sendMessage:)) {
//如果是这个方法的话，重新定义一个新的方法,映射过去
class_addMethod([self class], sel, imp_implementationWithBlock(^(id self, NSString *word) {
NSLog(@"word = %@", word);
//通过这种方法可以讲找不到的方法重新定义到别的方法去
[self sendOtherMessage:word];
}), "v@*");
}
return YES;
}
#pragma mark - Fast Forwarding
//- (id)forwardingTargetForSelector:(SEL)aSelector
//{
// if (aSelector == @selector(sendMessage:)) {
// return [MessageForwarding new];
// }
//
// return nil;
//}
#pragma mark - Normal Forwarding
- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector
{
NSMethodSignature *methodSignature = [super methodSignatureForSelector:aSelector];
if (!methodSignature) {
methodSignature = [NSMethodSignature signatureWithObjCTypes:"v@:*"];
}
return methodSignature;
}
- (void)forwardInvocation:(NSInvocation *)anInvocation
{
MessageForwarding *messageForwarding = [MessageForwarding new];
if ([messageForwarding respondsToSelector:anInvocation.selector]) {
[anInvocation invokeWithTarget:messageForwarding];
}
}
@end对象Second的声明：
//
// MessageForwarding.h
// RuntimeDemo
//
// Created by caijunrong on 7/15/15.
// Copyright © 2015 caijunrong. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface MessageForwarding : NSObject
- (void)sendMessage:(NSString *)word;
- (void)sendOtherMessage:(NSString *)word;
@end对象Second的实现：
// // MessageForwarding.m // RuntimeDemo // // Created by caijunrong on 7/15/15. // Copyright © 2015 caijunrong. All rights reserved. // #import "MessageForwarding.h" @implementation MessageForwarding - (void)sendMessage:(NSString *)word { NSLog(@"fast forwarding way : send message = %@", word); } - (void)sendOtherMessage:(NSString *)word{ NSLog(@"MessageForwarding sendOtherMessage word:%@",word); } @end
相关文章：
http://yulingtianxia.com/blog/2014/11/05/objective-c-runtime/
http://tech.glowing.com/cn/objective-c-runtime/
然后，关于里面的代码实现有2个比较不错的博客，可以参考
http://blog.sunnyxx.com
http://www.cnblogs.com/biosli/p/NSObject_inherit_2.html
另外还可以补充其他一些：
//-----------------------------------刨根问底Objective－C Runtime ---------------------
就这些基本能搞懂这个runtime的原理了。
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