NS调用；变量不是 CFString
我正在使用 NSInspiration 进行动态调用：
NSInvocation *lNSInvocation = [NSInvocation invocationWithMethodSignature: [lListener methodSignatureForSelector:lSelector]];
[lNSInvocation setTarget:lListener];
[lNSInvocation setSelector:lSelector];
// Note: Indexes 0 and 1 correspond to the implicit arguments self and _cmd, which are set using setTarget and setSelector.
[lNSInvocation setArgument:object atIndex:2];
[lNSInvocation setArgument:object2 atIndex:3];
[lNSInvocation setArgument:object3 atIndex:4];
[lNSInvocation invoke];
在调试器中，所有三个对象变量都正确指向三个不同的 NSCFString*。调用完成，另一端到达正确的方法。
- (void)login:(NSString*)username password:(NSString*)password host:(NSString*)host
但是，在调试器中，其参数给出错误：“变量不是 CFString”。更糟糕的是；所有三个变量都指向同一内存位置。
怎么会这样呢？
I'm making a dynamic call using NSInvocation:
NSInvocation *lNSInvocation = [NSInvocation invocationWithMethodSignature: [lListener methodSignatureForSelector:lSelector]];
[lNSInvocation setTarget:lListener];
[lNSInvocation setSelector:lSelector];
// Note: Indexes 0 and 1 correspond to the implicit arguments self and _cmd, which are set using setTarget and setSelector.
[lNSInvocation setArgument:object atIndex:2];
[lNSInvocation setArgument:object2 atIndex:3];
[lNSInvocation setArgument:object3 atIndex:4];
[lNSInvocation invoke];
In the debugger all three object variables correctly point to three different NSCFString*. The invocation is done and on the other side the correct method is reached.
- (void)login:(NSString*)username password:(NSString*)password host:(NSString*)host
However, in the debugger its parameters give an error: "variable is not a CFString". Even worse; all three variables point to the same memory location.
How can this be?
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（1）
如果方法参数是对象，则
-setArgument:atIndex:需要一个指向可从中复制对象的变量的指针。因此，如果你的字符串是：那么你应该写：（
注意每个对象参数之前的＆符号）
If the method arguments are objects,
-setArgument:atIndex:expects a pointer to the variable from which the object can be copied. Consequently, if your strings are:then you should write:
(note the ampersand before each object argument)