objective-c - 为什么我在尝试 NSScanner 在 NSString 语句中使用时收到错误消息？

Question

我想知道为什么会收到错误消息

Thread 1: Program received signal: "SIGABRT")

当我使用这行代码时：

NSScanner *userEntered = [[NSScanner alloc] scannerWithString:temp];

错误是：

2011-04-18 02:06:11.995 XXX[25929:207] -[NSConcreteScanner scannerWithString:]: unrecognized selector sent to instance 0x6816bc0
2011-04-18 02:06:11.999 XXX[25929:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSConcreteScanner scannerWithString:]: unrecognized selector sent to instance 0x6816bc0'

谢谢你。

Answer 1

+scannerWithString 是一个类方法，应该按以下方式使用：

NSScanner *userEntered = [NSScanner  scannerWithString:temp];