奇怪的NSNumberFormatter崩溃

Question

代码很简单：

static NSNumberFormatter *numberFormatter = nil;

if (numberFormatter == nil) {
    numberFormatter = [[NSDateFormatter alloc] init];
    [numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
}

然而，它在最后一行崩溃了：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSDateFormatter setNumberStyle:]: unrecognized selector sent to instance 0x5c378d0'

怎么可能？

Answer 1

因为您创建了NSDateFormatter，而不是NSNumberFormatter。