iOS_js代码如何转换oc代码?

一丶原理

1.利用 可以实现js和oc的消息传递;

2.利用反射机制,根据消息处理对应事情;

3.利用oc语言的动态特性,动态地创建对象,实现对象方法;

二丶原理探索

利用

JSContext *context = [[JSContext alloc] init];

context[@"hello"] = ^(NSString *msg){
    
    NSLog(@"%@",msg);
};
[context evaluateScript:@"hello('word')"];

生成一个View 的OC代码:

//原生实现
    UIView *redView = [[UIView alloc] init];
    redView.frame = CGRectMake(0, 0, 100, 100);
    redView.backgroundColor = [UIColor redColor];
    [self.view addSubview:redView];

Paste_Image.png

利用反射机制

  
    NSDictionary *creatClassDict = @{@"class":@"UIView",
                                     @"backgroundColor":@{@"key":@"backgroundColor",@"class":@"UIColor",@"value":@"yellowColor"},
                                     @"selector":@"addSubview:",
                                     @"frame":@{@"key":@"frame",@"value":@"{{100, 100}, {100, 100}}"}
                                     };
    
    //反射机制
    Class objClass = NSClassFromString(creatClassDict[@"class"]);
    id yellowView = [[objClass alloc] init];
    Class colorClass = NSClassFromString(creatClassDict[@"backgroundColor"][@"class"]);
    SEL colorSelector = NSSelectorFromString(creatClassDict[@"backgroundColor"][@"value"]);
    
    IMP colorImp = [colorClass methodForSelector:colorSelector];
    id (*colorfunc)(id, SEL) = (void *)colorImp;
    id color = colorfunc(colorClass, colorSelector);
    
    [yellowView setValue:color forKey:creatClassDict[@"backgroundColor"][@"key"]];
    
    [yellowView setValue:[NSValue valueWithCGRect:CGRectFromString(creatClassDict[@"frame"][@"value"])] forKey:creatClassDict[@"frame"][@"key"]];
    
    SEL selector = NSSelectorFromString(creatClassDict[@"selector"]);
    IMP imp = [self.view methodForSelector:selector];
    void *(*func)(id, SEL, UIView *) =(void *) imp;
    func(self.view, selector, yellowView);
    
    
    /*总结,需要的参数:
     UIView;
     backgroundColor = UIColor(yellowColor);
     frame : {{100, 100}, {100, 100}}
     self.view:addSubview(yellowView);
     */

Paste_Image.png

三丶js调用oc

    JSContext *context = [[JSContext alloc] init];
    
    context[@"hello"] = ^(NSString *msg){
      
        NSDictionary *creatClassDict =  [msg dictionaryWithJsonString];
        
        Class objClass = NSClassFromString(creatClassDict[@"class"]);
        id yellowView = [[objClass alloc] init];
        Class colorClass = NSClassFromString(creatClassDict[@"backgroundColor"][@"class"]);
        SEL colorSelector = NSSelectorFromString(creatClassDict[@"backgroundColor"][@"value"]);
        
        IMP colorImp = [colorClass methodForSelector:colorSelector];
        id (*colorfunc)(id, SEL) = (void *)colorImp;
        id color = colorfunc(colorClass, colorSelector);
        
        [yellowView setValue:color forKey:creatClassDict[@"backgroundColor"][@"key"]];
        
        [yellowView setValue:[NSValue valueWithCGRect:CGRectFromString(creatClassDict[@"frame"][@"value"])] forKey:creatClassDict[@"frame"][@"key"]];
        
        SEL selector = NSSelectorFromString(creatClassDict[@"selector"]);
        IMP imp = [self.view methodForSelector:selector];
        void *(*func)(id, SEL, UIView *) =(void *) imp;
        func(self.view, selector, yellowView);
        
        
        NSLog(@"%@",creatClassDict);
    };
    [context evaluateScript:@"hello('{\"class\":\"UIView\",\"backgroundColor\":{\"key\":\"backgroundColor\",\"class\":\"UIColor\",\"value\":\"yellowColor\"},\"selector\":\"addSubview:\",\"frame\":{\"key\":\"frame\",\"value\":\"{{100, 100}, {100, 100}}\"}}')"];

指定js调用oc的规则,对实现的封装,就应该可以实现js调用oc;

四丶可以看JSPatch的实现

http://blog.cnbang.net/tech/2808/