有時
[str isEqualToString:@""]并不好用,所以整理下面幾種方法判斷字符串是否為空
1. if (str == nil || str == NULL)
2. if ([str isKindOfClass:[NSNull class]])
3. if ([[str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0)
有時
[str isEqualToString:@""]并不好用,所以整理下面幾種方法判斷字符串是否為空
1. if (str == nil || str == NULL)
2. if ([str isKindOfClass:[NSNull class]])
3. if ([[str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0)