我对iOS开发人员网站上的某些项目感到困惑,需要解释。在下面的例子中,A,B的属性/变量将被更新,但它没有。以下代码所在的页面。
这些是属性/变量
- A)
self.badgeView.firstName
- B)
NSDate *originalDate
以下是 2 个代码片段:
NSMutableString *nameString = [NSMutableString stringWithString:@"John"];
self.badgeView.firstName = nameString;
[nameString appendString:@"ny"];
NSDate *originalDate = self.lastModificationDate;
self.lastModificationDate = [NSDate date];
NSLog(@"Last modification date changed from %@ to %@", originalDate, self.lastModificationDate);
这些
NSString
属性,如果以正确的方式实现,将复制你传递的参数。
NSMutableString *nameString = [NSMutableString stringWithString:@"John"];
self.badgeView.firstName = nameString;
[nameString appendString:@"ny"];
// you'll have to update it again, if you want that view's string updated:
self.badgeView.firstName = nameString;