一.消息機(jī)制

1.在viewDidLoad中直接用 performSelector:@selector(doSomething) 來調(diào)用doSomething方法時(shí),會(huì)發(fā)現(xiàn)找不到這個(gè)方法而奔潰.此時(shí),我們可以在resolveInsantanceMethod:(SEL)see 方法中獲取這個(gè)所有在運(yùn)行時(shí)階段的方法,在這個(gè)方法中只需要判斷一下,將這個(gè)方法獲取,并且運(yùn)用Runtime 的 class_addMethod 的方法來將方法和響應(yīng)函數(shù)綁定,進(jìn)而達(dá)到為某一個(gè)類添加方法的目的.

- (void)viewDidLoad {
    [superviewDidLoad];
    [selfperformSelector:@selector(doSomething)];

}

//1.對象在收到無法解讀的消息后,會(huì)調(diào)用resolveInstanceMethod

//2.再用class_addMethod 將調(diào)用的方法名字和制定函數(shù)相關(guān)聯(lián)

+ (BOOL)resolveInstanceMethod:(SEL)sel {

    if (sel == @selector(doSomething)) {
        NSLog(@"add method here");
        class_addMethod([selfclass], sel, (IMP)dynamicMethodIMP, "v@:");
        returnYES;
    }
    return [superresolveInstanceMethod:sel];

}

//函數(shù)

void dynamicMethodIMP (idself,SEL_cmd) {
    NSLog(@"doSomething SEL");

}

+ (BOOL)resolveClassMethod:(SEL)sel {
    NSLog(@">> Class resolving %@",NSStringFromSelector(sel));
    return [superresolveClassMethod:sel];

}

                              二.消息轉(zhuǎn)發(fā)

#import "ViewController.h"

@interfaceViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [superviewDidLoad];
    [selfperformSelector:@selector(messageViewMethod)];
}

/**
 *  @author zhouyantong
 *
 *  @brief 在這個(gè)方法中并沒有找到或者實(shí)現(xiàn)相應(yīng)的方法,那么消息會(huì)往下傳遞,在轉(zhuǎn)發(fā)方法中看別的界面是否有這個(gè)方法
 *
 */
+ (BOOL)resolveInstanceMethod:(SEL)sel {
    return [superresolveInstanceMethod:sel];
}

- (id)forwardingTargetForSelector:(SEL)aSelector {
    Class class = NSClassFromString(@"MessageViewController");
    UIViewController *vc = class.new;
    if (aSelector == NSSelectorFromString(@"messageViewMethod")) {
        NSLog(@"MessageVC do this!");
        return vc;
    }
    returnnil;
}

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

}

 

 

 

#import "MessageViewController.h"

@interfaceMessageViewController ()

@end

@implementation MessageViewController

- (void)viewDidLoad {
   
}

- (void)messageViewMethod {
    NSLog(@"This is receive method!");
}

@end