第四章 Runtime应用：方法添加

不念不忘少年蓝@ 2022-05-21 12:10 134阅读 0赞

方法添加

class_addMethod(Class _Nullable cls, SEL _Nonnull name, IMP _Nonnull imp, const char * _Nullable types)

> 1、cls 被添加方法的类  
> 2、name 添加的方法的名称的SEL  
> 3、imp 方法的实现。该函数必须至少要有两个参数，self,\_cmd  
> 4、类型编码

示例`class_addMethod([self class], sel, (IMP)fooMethod, "v@:");`

代码示例

#import "ViewController.h"
    #import "Person.h"
    #import "NSMutableArray+RunTime.h"
    #import "UIViewController+RunTime.h"
    #import "UIView+RunTime.h"
    #import <objc/runtime.h>
    #import <objc/message.h>
    
    @interface ViewController ()
    {
        NSMutableArray *names;
    }
    
    @end
    
    @implementation ViewController
    
    - (void)viewDidLoad {
        [super viewDidLoad];
        // Do any additional setup after loading the view, typically from a nib.
    
        self.title = @"runtime";
    
        self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"click" style:UIBarButtonItemStyleDone target:self action:@selector(buttonClick)];
    
        // 执行work函数
        [self performSelector:@selector(work:)];
    }
    
    #pragma mark - 消息转发（方法添加）
    
    + (BOOL)resolveInstanceMethod:(SEL)sel
    {
        if (sel == @selector(work:))
        {
            // 如果是执行work函数，就动态解析，指定新的IMP
            class_addMethod([self class], sel, (IMP)workMethod, "v@:");
            return YES;
        }
        return [super resolveInstanceMethod:sel];
    }
    
    void workMethod(id obj, SEL _cmd)
    {
        // 新的work函数
        NSLog(@"Doing work");
    }
    
    - (void)didReceiveMemoryWarning {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }
    
    @end