runtime的常用方法.md

runtime的常用方法

1.给类别加属性

预设 char 值

static char WarningViewKey;

GET方法:objc_getAssociatedObject

- (CustomerWarnView *)warningView{
    return objc_getAssociatedObject(self, &WarningViewKey);
}

SET方法:objc_setAssociatedObject

- (void)setWarningView:(CustomerWarnView *)warningView{
    [self willChangeValueForKey:@"WarningViewKey"];
    objc_setAssociatedObject(self, &WarningViewKey, warningView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    [self didChangeValueForKey:@"WarningViewKey"];
}

2.替换（重写）方法

核心代码:

Method a = class_getInstanceMethod(self, @selector(sendAction:to:forEvent:));
    Method b = class_getInstanceMethod(self, @selector(rc_sendAction:to:forEvent:));
    method_exchangeImplementations(a, b);

例子:

+ (void)load
{
    //替换点击事件
    Method a = class_getInstanceMethod(self, @selector(sendAction:to:forEvent:));
    Method b = class_getInstanceMethod(self, @selector(rc_sendAction:to:forEvent:));
    method_exchangeImplementations(a, b);
}

- (void)rc_sendAction:(SEL)action to:(id)target forEvent:(UIEvent *)event
{
    if (self.ignoreClick) {
        return;
    }
    else{
        [self rc_sendAction:action to:target forEvent:event];
    }
    if (self.clickInterval > 0)
    {
        self.ignoreClick = YES;
        [self performSelector:@selector(setIgnoreClick:) withObject:@(NO) afterDelay:self.clickInterval];
    }
    
}

3.通过类名(字符串)初始化对象

可以简化代码提高复用:NSClassFromString

Class classVC = NSClassFromString(@"类名");
[classVC new];

4.通过方法名(字符串)调用该方法

使用:NSSelectorFromString

SEL normalSelector = NSSelectorFromString(methodName);
    if ([self respondsToSelector:normalSelector]) {
        
        ((void (*)(id, SEL))objc_msgSend)(self, normalSelector);
    }