- (void)viewDidLoad

{

    [super viewDidLoad];

    // Do any additional setup after loading the view.

    self.title=@"判断字符串是否为空";

    NSLog(@"-isEmpty--%i--",[self isEmpty:@"123"]);

}

//判断字符串是否为空

-(BOOL)isEmpty:(NSString *)str

{

    if(!str)

    {

        return true;

    }

    else

    {

        NSCharacterSet *set=[NSCharacterSet whitespaceAndNewlineCharacterSet];

        NSString *trimedString=[str stringByTrimmingCharactersInSet:set];

        if([trimedString length]==0)

        {

            return true;

        }

        else

        {

            return false;

        }

    }

}

2015-10-19 15:38:15.642 判断字符串是否为空[9406:236480] -isEmpty--0--