Objective-C how to check if a string is null

Posted by norskben on Stack Overflow See other posts from Stack Overflow or by norskben
Published on 2010-03-08T12:29:29Z Indexed on 2010/03/08 12:36 UTC
Read the original article Hit count: 975

Filed under:

objective-c

|

nil

|

nsstring

SO I wish to check to see if the item in my array [clientDataArray objectForKey:@"ClientCompany"] is nil.

    temp = [clientDataArray objectForKey:@"ClientCompany"];
    if (temp != [NSNull null]) infofieldCompany.text = temp;

So far I have been able to achieve this through the above code, but it does give me the warnings

warning: 'NSArray' may not respond to'-objectForKey:'
warning: comparison of distinct Objective-C types 'struct NSNull *' and 'struct NSString *' lacks a cast

My main interest is the second warning, but the first warning also interest me. How should I adapt my above code?

© Stack Overflow or respective owner

Related posts about objective-c

Blocking access to websites with objective-C / root privileges in objective-C

as seen on Stack Overflow - Search for 'Stack Overflow'
I am writing a program in Objective-C (XCode 3.2, on Snow Leopard) that is capable of either selectively blocking certain sites for a duration or only allow certain sites (and thus block all others) for a duration. The reasoning behind this program is rather simple. I tend to get distracted when I… >>> More
Objective-C with some Objective-C++, calling a normal c++ method "referenced from" problem

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I made an Objective-C project for the iPhone. I had only one cpp class, the soundEngine taken from some Apple demo. Now I'm trying to merge OpenFeint which is coded in Objective-C++. As soon as I drop in the code without even referring to it from my code, when I hit Build, my Objective-C code… >>> More
Add an objective @property attribute in objective-c

as seen on Stack Overflow - Search for 'Stack Overflow'
Does anyone know of a way to add additional attribute types to the @property keyword without modifying the compiler? Or can anyone think of another way to genericize getter/setter creation? Basically, I have a lot of cases in a recent project where it's handy for objects to lazily instantiate their… >>> More
ObjectiveC Syntax for Specifying Protocol Name in Method Argument

as seen on Stack Overflow - Search for 'Stack Overflow'
What's the ObjectiveC syntax for specifying a protocol as an argument in a method? Say I have 2 protocols, MyProtocol and MyProtocolCB: @protocol MyProtocolCB <NSObject> - (void) func; @end @protocol MyProtocol <NSObject> - (void) register:(MyProtocolCB*) cb; @end I'm receiving this… >>> More
ObjectiveC builtin template system ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I am developing an iPhone application and I use HTML to display formatted text. I often display the same webpage, but with a different content. I would like to use a template HTML file, and then fill it with my diffent values. I wonder if ObjectiveC has a template system similar to ERB in Ruby. That… >>> More

Related posts about nil

What's the effect in Ruby when you initialize with nil: x = String(nil)

as seen on Stack Overflow - Search for 'Stack Overflow'
What's the effect in Ruby when you pass nil to the constructor as in: s = String(nil) or a = Array(nil) Does this mean that s or a is nil or that s or a is an unpopulated object of type String or type Array? >>> More
In Ruby, what is good way to filter all the methods of an object that contain the word "time" in it?

as seen on Stack Overflow - Search for 'Stack Overflow'
I tried the following and it was partly working: >> s.methods.map {|n| n if n =~ /time/} => [nil, nil, nil, nil, nil, nil, nil, nil, "skip_time_zone_conversion_for_attri butes", nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, ni l, nil, nil, nil, nil, nil, nil, nil… >>> More
Getting ActiveRecord (Rails) to_xml to use xsi:nil and xsi:type instead of nil and type

as seen on Stack Overflow - Search for 'Stack Overflow'
The default behavior of XML serialization (to_xml) for ActiveRecord objects will emit 'type' and 'nil' attributes that are similar to XML Schema Instance attributes, but aren't set in a XML Namespace. For example, a model might produce an output like this: <user> <username nil="true"… >>> More
Ubuntu 12.04 can't detect internal mobile broadband (Gobi 2000)

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Hi I have been trying Ubuntu to detect and connect using the buit in mobile broadband capability in my HP 110 netbook but until now nothing seems to work Output of lspci command: 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2) 00:1f.0 ISA bridge: Intel Corporation 82801GBM… >>> More
undefined method `build_users' with nested models

as seen on Stack Overflow - Search for 'Stack Overflow'
I've got into trouble with nested attributes. Here is my Account model : class Account < ActiveRecord::Base has_many :products has_many :blogs has_many :openings has_many :users has_one :logo, :class_name => "AccountPicture" has_one :address, :class_name => "AccountAddress" … >>> More