iphone - 在 Objective C 中检查 NSString 的 NOT 值的条件

Question

代码:

NSString *tempPhone = [NSString stringWithFormat:@"%@", [personDict objectForKey:kPhoneKey]];
NSLog(@"NSString *tempPhone = %@",tempPhone);

输出:

NSString *tempPhone = <null>

现在我想添加if条件，for not null;我尝试了以下方法:

if (tempEmail != NULL)
if (tempPhone != Nil)
if (tempPhone != nil)
if (![tempPhone compare:@"<null>"])
if (tempPhone != (NSString*)[NSNull null])

我还检查了this Post.

他们都不适合我。我哪里错了？？

Answer 1

试试下面的代码

id phoneNo = [personDict objectForKey:kPhoneKey];

if( phoneNo && ![phoneNo isKindOfClass:[NSNull class]] )
{
    NSString *tempPhone = [NSString stringWithFormat:@"%@", [personDict objectForKey:kPhoneKey]];
    NSLog(@"NSString *tempPhone = %@",tempPhone);
}
else
{
    NSLog(@"NSString *tempPhone is null");
}