This isn&#39;t exactly the third level, mind you. An URL is split like that way:

* the protocol or scheme (here, `http`)
* the `://` delimiter
* the username and the password (here there isn&#39;t any, but it could be `username:password@hostname`)
* the host name (here, `digg.com`)
* the port (that would be `:80` after the domain name for instance)
* the path (here, `/news/business/24hr`)
* the parameter string (anything that follows a semicolon)
* the query string (that would be if you had GET parameters like `?foo=bar&amp;baz=frob`)
* the fragment (that would be if you had an anchor in the link, like `#foobar`).

A &quot;fully-featured&quot; URL would look like this:

&lt;!-- lang: lang-none --&gt;

    http://foobar:nicate@example.com:8080/some/path/file.html;params-here?foo=bar#baz

`NSURL` has a wide range of accessors. You may check them in the documentation for the [`NSURL`][1] class, section _Accessing the Parts of the URL_. For quick reference:

 * `-[NSURL scheme]` = http
 * `-[NSURL resourceSpecifier]` = (everything from // to the end of the URL)
 * `-[NSURL user]` = foobar
 * `-[NSURL password]` = nicate
 * `-[NSURL host]` = example.com
 * `-[NSURL port]` = 8080
 * `-[NSURL path]` = /some/path/file.html
 * `-[NSURL pathComponents]` = @[&quot;/&quot;, &quot;some&quot;, &quot;path&quot;, &quot;file.html&quot;] (note that the initial / is part of it)
 * `-[NSURL lastPathComponent]` = file.html
 * `-[NSURL pathExtension]` = html
 * `-[NSURL parameterString]` = params-here
 * `-[NSURL query]` = foo=bar
 * `-[NSURL fragment]` = baz

What you&#39;ll want, though, is something like that:

    NSURL* url = [NSURL URLWithString:@&quot;http://digg.com/news/business/24hr&quot;];
    NSString* reducedUrl = [NSString stringWithFormat:
    	@&quot;%@://%@/%@&quot;,
    	url.scheme,
    	url.host,
    	url.pathComponents[1]];

For your example URL, what you seem to want is the protocol, the host and the first path component. (The element at index 0 in the array returned by `-[NSString pathComponents]` is simply &quot;/&quot;, so you&#39;ll want the element at index 1. The other slashes are discarded.)

  [1]: https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSURL_Class/Reference/Reference.html

[![Using Playground , language swift, I got this !][1]][1]
Playground provides an interactive way of seeing this in action. I hope you can enjoy doing the same, a fun way to learn NSURL an important topic in iOS.

  [1]: https://i.stack.imgur.com/x7dCx.png

Should logger be declared static or not? Usually I&#39;ve seen two types of declaration for a logger :
&lt;pre&gt;
    protected Log log = new Log4JLogger(aClass.class);
&lt;/pre&gt;

or

&lt;pre&gt;
    private static Log log = new Log4JLogger(aClass.class);
&lt;/pre&gt;

Which one should be used? what are the pro&#39;s and con&#39;s of both?

Should logger be private static or not

Once the user is on my page, I do not want him to refresh the page.

1. Anytime, the user hits &lt;kbd&gt;F5&lt;/kbd&gt; or refresh button on top. He should get an alert saying 

   &gt; You cannot refresh the page. 

2. Also if the user opens a new tab and tries to access the same url in prev tab he should get an alert 

   &gt; You cannot open same page in 2 tabs

Anyway I can do this using JavaScript or jQuery? Point one is really important.

Prevent any form of page refresh using jQuery/Javascript

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 an NSString with the value of
<pre><code class="hljs language-ruby">http://digg.com/news/business/24hr
</code></pre>
How can I get everything before the 3rd level?
<pre><code class="hljs language-arduino">http://digg.com/news/
</code></pre>

How can I get the year/month/day of a `NSDate` object, given no other information? I realize that I could probably do this with something similar to this:

    NSCalendar *cal = [[NSCalendar alloc] init];
    NSDateComponents *components = [cal components:0 fromDate:date];
    int year = [components year];
    int month = [components month];
    int day = [components day];

But that seems to be a whole lot of hassle for something as simple as getting a `NSDate`&#39;s year/month/day. Is there any other solution?

NSDate get year/month/day

    - (void)someMethod
    {
        if ( [delegate respondsToSelector:@selector(operationShouldProceed)] )
        {
            if ( [delegate operationShouldProceed] )
            {
                // do something appropriate
            }
        }
    }

The [documentation][1] says:

&gt; The precaution is necessary only for optional methods in a formal protocol or methods of an informal protocol

What does it mean? If I use a formal protocol I can just use `[delegate myMethod]`?


  [1]: http://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CocoaFundamentals/CommunicatingWithObjects/CommunicateWithObjects.html#//apple_ref/doc/uid/TP40002974-CH7-SW29

when to use respondsToSelector in objective-c

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?

Understanding NSString comparison

I have a text file having data as given

e.g. 

    PUFGUjVRallYZDNaazFtVjVObU1zWm5ZcUJUYU5ORk4zbGthNHNDVUdSMlFVQmpSVEoxUUNSallYaFhkanBITXBGR1NTQnpZRTltZE1OalVzSkdXQ0Z6WXR0V2RpTmpTdXgwTWs5V1lZSkZiWjFXT29OV2JSVlhaSTUwYUpwR040UUZXTzVHVXFoWFVRcFdWNHdVTUJ0Q1VHSmxXVlJVTlJCMVE1VTFWV
    PUFGUjVRallYZDNaazFtVjVObU1zWm5ZcUJUYU5ORk4zbGthNHNDVUdSMlFVQmpSVEoxUUNSallYaFhkanBITXBGR1NTQnpZRTltZE1OalVzSkdXQ0Z6WXR0V2RpTmpTdXgwTWs5V1lZSkZiWjFXT29OV2JSVlhaSTUwYUpwR040UUZXTzVHVXFoWFVRcFdWNHdVTUJ0Q1VHSmxXVlJVTlJCMVE1VTFWV

Now I want to read data line by line. That means first I want to read

    PUFGUjVRallYZDNaazFtVjVObU1zWm5ZcUJUYU5ORk4zbGthNHNDVUdSMlFVQmpSVEoxUUNSallYaFhkanBITXBGR1NTQnpZRTltZE1OalVzSkdXQ0Z6WXR0V2RpTmpTdXgwTWs5V1lZSkZiWjFXT29OV2JSVlhaSTUwYUpwR040UUZXTzVHVXFoWFVRcFdWNHdVTUJ0Q1VHSmxXVlJVTlJCMVE1VTFWV

and then next remaining.
anyone have any idea??

How to read data from NSFileHandle line by line?

Which is the proper delegate to implement when an application is waking up from being in the background and you want it to prep it to be active?

applicationWillEnterForeground vs applicationDidBecomeActive -- What&#39;s the difference?

Which is the proper delegate to implement for when an application is going to sleep and you want to prep it to cleanup and save data?

applicationWillResignActive vs. applicationDidEnterBackground -- What&#39;s the difference?

Also, I&#39;ve noticed that applicationWillResignActive gets called when an incoming SMS or call comes in but the user chooses to click Ok and continue.  I don&#39;t want my app to take any action in these cases.  I just want it to keep running without any intermediate cleanup since the user didn&#39;t exit the app.  So, I would think it makes more sense to do cleanup work just in applicationDidEnterBackground.

I would appreciate your input on best practices to follow on choosing which delegates to implement for waking up and going to sleep as well as considering events like being interrupted by SMS/calls.

Thanks

applicationWillEnterForeground vs. applicationDidBecomeActive, applicationWillResignActive vs. applicationDidEnterBackground

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

I need to use something like `NSLog` but without the timestamp and newline character, so I&#39;m using `printf`. How can I use this with `NSString`?

How to use printf with NSString

I want to get a character from somewhere inside an NSString. I want the result to be an NSString.

This is the code I use to get a single character at index it:

    [[s substringToIndex:i] substringToIndex:1]
Is there a better way to do it?

How to get a single NSString character from an NSString

How would I convert an `NSString` like &quot;**01/02/10**&quot; (meaning 1st February 2010) into an `NSDate`? And how could I turn the `NSDate` back into a string?

Converting NSString to NSDate (and back again)

I have a URL like `myApp://action/1?parameter=2&amp;secondparameter=3`

With the property query I get following part of my `URL`

    parameter=2&amp;secondparameter=3

Is there any way easy to put this in a `NSDictionary` or an `Array`?

Thx a lot


Parse NSURL query property

Let&#39;s say I have an `NSURL`? Whether or not it already has an empty query string, how do I add one or more parameters to the `query` of the `NSURL`? I.e., does anyone know of an implementation of this function?

    - (NSURL *)URLByAppendingQueryString:(NSString *)queryString

So that it satisfies this `NSURL+AdditionsSpec.h` file:

    #import &quot;NSURL+Additions.h&quot;
    #import &quot;Kiwi.h&quot;
    
    SPEC_BEGIN(NSURL_AdditionsSpec)
    
    describe(@&quot;NSURL+Additions&quot;, ^{
        __block NSURL *aURL;
    
        beforeEach(^{
            aURL = [[NSURL alloc] initWithString:@&quot;http://www.example.com&quot;];
            aURLWithQuery = [[NSURL alloc] initWithString:@&quot;http://www.example.com?key=value&quot;];
        });
    
        afterEach(^{
            [aURL release];
            [aURLWithQuery release];
        });
    
        describe(@&quot;-URLByAppendingQueryString:&quot;, ^{
            it(@&quot;adds to plain URL&quot;, ^{
                [[[[aURL URLByAppendingQueryString:@&quot;key=value&amp;key2=value2&quot;] query] should]
                 equal:@&quot;key=value&amp;key2=value2&quot;];
            });
    
            it(@&quot;appends to the existing query sting&quot;, ^{
                [[[[aURLWithQuery URLByAppendingQueryString:@&quot;key2=value2&amp;key3=value3&quot;] query] should]
                 equal:@&quot;key=value&amp;key2=value2&amp;key3=value3&quot;];
            });
        });
    });
    
    SPEC_END




Objective-C: How to add query parameter to NSURL?

I have an app where the user can choose an image either from the built-in app images or from the iphone photo library. I use an object Occasion that has an `NSString` property to save the `imagePath`. 

Now in the case of the built-in app images I do get the file name as an `NSString` an save in the `[occasion imagePath]`. But in the 2nd case where the user picks an image form the photo library I get an `NSURL` which I want to convert to an `NSString` to be able to save it in `[occasion imagePath`].

Is it possible to convert the `NSURL` to an `NSString`?


Convert an NSURL to an NSString

I need to load an image from a url and set it inside an UIImageView; the problem is that I don&#39;t know the exact size of the image, then how can I show the image correctly?

iOS: load an image from url

I&#39;ve been trying to use Corona SDK&#39;s Facebook API to post the score on the game I&#39;m developing on facebook. However, I&#39;m having a problem with it. During the first time I try to post to facebook, I get this error after login and user authentication:

&gt; NSURLErrorDomain error code -999

Then, it won&#39;t post on facebook. What are possible causes of this error and how can I address it? I tried searching the web but couldn&#39;t find information about it. Thanks in advance.

By the way, I am not using webview on my app. Just the widget api and a show_dialog listener in my Facebook class.

Content Type	Original Author	Original Content on Stackoverflow
Question	Melina	View Question on Stackoverflow
Solution 1 - Objective C	zneak	View Answer on Stackoverflow
Solution 2 - Objective C	Kumar Utsav	View Answer on Stackoverflow

Get parts of a NSURL in objective-c

Objective C Problem Overview

Objective C Solutions

Solution 1 - Objective C

Solution 2 - Objective C

Prevent any form of page refresh using jQuery/Javascript

Should logger be private static or not

Attributions