獲取成員變數有兩種方法：

通過 class_copyPropertyList 獲取的成員變數僅僅是物件類的屬性（@property宣告的屬性）

  unsigned int count = 0;
        objc_property_t *properties = class_copyPropertyList([UITextField class], &count);
    
        for (int i = 0; i<count; i++) {
            objc_property_t property = properties[i];
            NSLog(@"%s",property_getName(property));
        }
    
        free(properties);
 

還有一種是通過copyIvarList 獲取，這種方法獲取的是所有屬性和變數(包括在@interface大括號中宣告的變數)

 unsigned int count = 0;
    Ivar *ivars = class_copyIvarList([UITextField class], &count);
    
    for (int i = 0; i<count; i++) {
        Ivar property = ivars[i];
        NSLog(@"%s---%@",ivar_getName(property),[NSString stringWithUTF8String:ivar_getName(property)]);
    }
    
    free(ivars);