    NSString *code = [state substringFromIndex: [state length] - 2];

should do it


**Swift 4:**

    let code = (state as? NSString)?.substring(from: state.characters.count - 2)

I&#39;m a web application development noob. I have a function that opens a file and reads it. Unfortunately, the directory structures between the test and production servers differ. I was told to &quot;use a path relative to ~&quot;. I haven&#39;t been able to find any resources on the &#39;~&#39;, though!

How do I use the tilde character in the context of paths?

EDIT: This is in Python. I fixed the problem, using [os.path.expanduser(&#39;~/path/in/home/area&#39;)][1].


  [1]: https://docs.python.org/3/library/os.path.html#os.path.expanduser

How do I use &#39;~&#39; (tilde) in the context of paths?

I&#39;m creating a custom widget by extending `LinearLayout`:

    public class MyWidget extends LinearLayout {
        private static Paint PAINT = new Paint(Paint.ANTI_ALIAS_FLAG);
        static {
            PAINT.setColor(Color.RED);
        }

        public MyWidget(Context context) {
            this(context, null);
        }

        public MyWidget(Context context, AttributeSet attrs) {
            super(context, attrs);
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            canvas.drawCircle(canvas.getWidth() / 2, canvas.getHeight()/2, canvas.getWidth()/2, PAINT);
            // never gets called :-(
        }
        
        @Override
        protected void dispatchDraw(Canvas canvas) {
            super.dispatchDraw(canvas);
            // this gets called, but with a canvas sized after the padding.
        }
    }

I can add children just fine, but I&#39;m never getting my custom `onDraw()` being called. `dispatchDraw()` gets called, but that seems to have a different canvas (the one that&#39;s within the padding. I need to draw on the whole layout area). Is there some flag that needs to get set to get `onDraw()` called for the layout?

Custom Widget using LinearLayout not getting onDraw()

Say I have a string:

    NSString *state = @&quot;California, CA&quot;;

Can someone please tell me how to extract the last two characters from this string (`@&quot;CA&quot;` in this example).

Get last 2 characters of a string?

Say I have a string:
<pre><code class="hljs language-ini">NSString *state = @"California, CA";
</code></pre>
Can someone please tell me how to extract the last two characters from this string (<code>@"CA"</code> in this example).

What is the difference between a Category and a Class Extension. I believe both are used to add custom methods in existing classes. Can someone throw light on this? Examplification with code will be really appreciated.

Difference between Category and Class Extension?

How do I hide an NSTableView header completely, so that it does not take any space up?

Hiding NSTableView header?

I&#39;ve previously avoided underscores in my variable names, perhaps a holdover from my college Java days. So when I define a property in Objective C this is what I naturally do.

    // In the header
    @interface Whatever
    {
    	NSString *myStringProperty
    }
    
    @property (nonatomic, copy) NSString *myStringProperty;
    
    // In the implementation
    @synthesize myStringProperty;

But in almost every example it is done like

    // In the header
    @interface Whatever
    {
        NSString *_myStringProperty
    }
    
    @property (nonatomic, copy) NSString *myStringProperty;
    
    // In the implementation
    @synthesize myStringProperty = _myStringProperty;

Should I get over my aversion to the underscore because that is the one way it should be done, is there a good reason for this style being the preferred one?

**Update:** With automatic property synthesis nowadays you can leave out the @synthesize and the result is the same as if you&#39;d used  

    @synthesize myStringProperty = _myStringProperty;

which clearly shows you Apple&#39;s preference. I&#39;ve since learned to stop worrying and love the underscore.

Prefixing property names with an underscore in Objective C

I want to display an image next to a UILabel, however UILabel has variable text length, so I don&#39;t know where to place the image. How can I accomplish this?

How to calculate UILabel width based on text length?

Is there any way to check whether or not the current thread is the main thread in Objective-C?

I want to do something like this.

      - (void)someMethod
      {
        if (IS_THIS_MAIN_THREAD?) {
          NSLog(@&quot;ok. this is main thread.&quot;);
        } else {
          NSLog(@&quot;don&#39;t call this method from other thread!&quot;);
        }
      }

Check whether or not the current thread is the main thread

Hi I am trying to convert a standard `std::string` into an `NSString` but I&#39;m not having much luck.

I can convert successfully from an `NSString` to a `std::string` with the following code
    
    NSString *realm = @&quot;Hollywood&quot;;
    std::string REALM = [realm cStringUsingEncoding:[NSString defaultCStringEncoding]];

However I get a compile time error when I try the following
     
    NSString *errorMessage = [NSString stringWithCString:REALM encoding:[NSString defaultCStringEncoding]];

The error I get is 

    Cannot convert &#39;std::string&#39; to &#39;const char*&#39; in argument passing

Am I missing something here?

Thanks in advance.


How to convert std::string to NSString?

I have an NSString object and I want to make a substring from it, by locating a word.

For example, my string is: &quot;The dog ate the cat&quot;, I want the program to locate the word &quot;ate&quot; and make a substring that will be &quot;the cat&quot;.

Can someone help me out or give me an example?

Thanks,

Sagiftw

Finding a substring in a NSString object

I have an NSString with the value of

    http://digg.com/news/business/24hr

How can I get everything before the 3rd level?

    http://digg.com/news/

Get parts of a NSURL in objective-c

I have a `UITextView` that takes an `NSString` with formatting `stringWithUTF8String`. It is getting its values from a database and I want the text in the database to be rendered with breaks within the text. I tried using `\n` to do this but it gets rendered as text. Doing this in my information page of the app as straight text worked but I think the reason its not working when taking it from the database is because of the formatting. 

Any suggestions?

Adding a line break to a UITextView

Both the following comparisons evaluate to true:

1)

    @&quot;foo&quot; == @&quot;foo&quot;;

2)

    NSString *myString1 = @&quot;foo&quot;;
    NSString *myString2 = @&quot;foo&quot;;
    myString1 == myString2;

However, there are definitely times where two `NSString`s cannot be compared using the equality operator, and `[myString1 isEqualToString:myString2]` is required instead.  Can someone shed some light on this?

Content Type	Original Author	Original Content on Stackoverflow
Question	dpigera	View Question on Stackoverflow
Solution 1 - Objective C	Ferruccio	View Answer on Stackoverflow
Solution 2 - Objective C	Naishta	View Answer on Stackoverflow

Get last 2 characters of a string?

Objective C Problem Overview

Objective C Solutions

Solution 1 - Objective C

Solution 2 - Objective C

Custom Widget using LinearLayout not getting onDraw()

How do I use '~' (tilde) in the context of paths?

Attributions