**Objective-C**

    NSMutableCharacterSet *_alnum = [NSMutableCharacterSet characterSetWithCharactersInString:@&quot;_&quot;];
    [_alnum formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];

**Swift** 

    let _alnum = NSMutableCharacterSet(charactersIn: &quot;_&quot;)
    _alnum.formUnion(with: .alphanumerics)


Another way would have been to make it mutable and add it.

**Objective-C**

    NSMutableCharacterSet *characterSet = [NSMutableCharacterSet alphanumericCharacterSet];
    [characterSet addCharactersInString:@&quot;_&quot;];


**Swift**

    let characterSet = NSMutableCharacterSet.alphanumeric()
    characterSet.addCharacters(in: &quot;_&quot;)

You could verify it has been added (in a Playground) with: 

    characterSet.characterIsMember(UInt16(Character(&quot;^&quot;).unicodeScalars.first!.value)) // false
    characterSet.characterIsMember(UInt16(Character(&quot;_&quot;).unicodeScalars.first!.value)) // true -- YAY!
    characterSet.characterIsMember(UInt16(Character(&quot;`&quot;).unicodeScalars.first!.value)) // false


    - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

        NSCharacterSet *blockedCharacters = [[NSCharacterSet whitespaceCharacterSet] invertedSet];
        NSCharacterSet *blockedCharacters2 = [[NSCharacterSet letterCharacterSet] invertedSet];
        return ([string rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound || [string rangeOfCharacterFromSet:blockedCharacters2].location);  

    }

So, I have a page that loads and through jquery.get makes several requests to populate drop downs with their values.


    $(function() {
        LoadCategories($(&#39;#Category&#39;));
        LoadPositions($(&#39;#Position&#39;));
        LoadDepartments($(&#39;#Department&#39;));
	
        LoadContact();
    };

It then calls LoadContact(); Which does another call, and when it returns it populates all the fields on the form.  The problem is that often, the dropdowns aren&#39;t all populated, and thus, it can&#39;t set them to the correct value.

What I need to be able to do, is somehow have LoadContact only execute once the other methods are complete and callbacks done executing.

But, I don&#39;t want to have to put a bunch of flags in the end of the drop down population callbacks, that I then check, and have to have a recursive setTimeout call checking, prior to calling LoadContact();

Is there something in jQuery that allows me to say, &quot;Execute this, when all of these are done.&quot;?

**More Info**
I am thinking something along these lines

    $().executeAfter(
    	function () {	// When these are done
    	    LoadCategories($(&#39;#Category&#39;));
    	    LoadPositions($(&#39;#Position&#39;));
    	    LoadDepartments($(&#39;#Department&#39;));
    	},
    	LoadContact	// Do this
    );

...it would need to keep track of the ajax calls that happen during the execution of the methods, and when they are all complete, call LoadContact;

If I knew how to intercept ajax that are being made in that function, I could probably write a jQuery extension to do this. 

**My Solution**

    ;(function($) {
    	$.fn.executeAfter = function(methods, callback) {
    
    		var stack = [];
    
    		var trackAjaxSend = function(event, XMLHttpRequest, ajaxOptions) {
    			var url = ajaxOptions.url;
    
    			stack.push(url);
    		}
    
    		var trackAjaxComplete = function(event, XMLHttpRequest, ajaxOptions) {
    			var url = ajaxOptions.url;
    
    			var index = jQuery.inArray(url, stack);
    
    			if (index &gt;= 0) {
    				stack.splice(index, 1);
    			}
    
    			if (stack.length == 0) {
    				callback();
    				$this.unbind(&quot;ajaxComplete&quot;);
    			}
    		}
    
    		var $this = $(this);
    
    		$this.ajaxSend(trackAjaxSend)
    		$this.ajaxComplete(trackAjaxComplete)
    
    		methods();
    		$this.unbind(&quot;ajaxSend&quot;);
    	};
    })(jQuery);

This binds to the ajaxSend event while the methods are being called and keeps a list of urls (**need a better unique id though**) that are called.  It then unbinds from ajaxSend so only the requests we care about are tracked.  It also binds to ajaxComplete and removes items from the stack as they return.  When the stack reaches zero, it executes our callback, and unbinds the ajaxComplete event.

Waiting on multiple asynchronous calls to complete before continuing

I want to use `.data()` in my application. The [examples][1] are helpful, but I do not understand however where the values are stored.

I inspect the webpage with Firebug and as soon as .data() saves an object to a dom element, I do not see *any* change in Firebug (either HTML or Dom tabs).

I tried to look at jQuery source, but it is very advanced for my Javascript knowledge and I lost myself.

So the question is:

Where do the values stored by jQuery.data() actually go? Can I inspect/locate/list/debug them using a tool?



  [1]: http://api.jquery.com/jQuery.data/

How does jQuery .data() work?

Building an NSCharacter set to restrict a UITextField for entering user names. I want the user to be able to also enter an underscore (so [A-Za-z0-9_]) but alphanumericCharacterSet does not include it. Is there a way to specify a range like that in short form? I see `+ (id)characterSetWithRange:(NSRange)aRange`, but I&#39;m not really understanding how that would work.

I&#39;ve got a simple UITextField sub-class that I pass the character set to. The restriction works fine and doesn&#39;t allow the user to enter anything but alpha numeric. Just need to add the &quot;_&quot; to those allowances.

    NSCharacterSet *characterSet = [NSCharacterSet alphanumericCharacterSet];
    [textField setAllowed:characterSet];
    [textField setFrame:frame];


NSCharacterSet: How do I add &quot;_&quot; to alphanumericCharacterSet text restriction?

Building an NSCharacter set to restrict a UITextField for entering user names. I want the user to be able to also enter an underscore (so [A-Za-z0-9_]) but alphanumericCharacterSet does not include it. Is there a way to specify a range like that in short form? I see <code>+ (id)characterSetWithRange:(NSRange)aRange</code>, but I'm not really understanding how that would work.
I've got a simple UITextField sub-class that I pass the character set to. The restriction works fine and doesn't allow the user to enter anything but alpha numeric. Just need to add the "_" to those allowances.
<pre><code class="hljs language-ini">NSCharacterSet *characterSet = [NSCharacterSet alphanumericCharacterSet];
[textField setAllowed:characterSet];
[textField setFrame:frame];
</code></pre>

I&#39;m trying to figure out why something with Javascript isn&#39;t working inside of a UIWebView. To my knowledge, there is no way to set a breakpoint inside of XCode for a js file. No problemo, I&#39;ll just go back to 2004 and use alert statemen-- oh wait they don&#39;t seem to work inside of a UIWebView either!

The only thing I could think of is by exporting my HTML And JS files to my desktop and then just doing my debugging inside of Safari. And that works! But of course, the bug I&#39;m fighting with in the UIWebView doesn&#39;t occur in Safari. 

Are there any other ways for debugging inside of a UIWebView, or any tricks that I can use akin to using the old-school alert method?

What are some methods to debug Javascript inside of a UIWebView?

Currently, we are defining ourselves an extended log mechanism to print out the class name and the source line number of the log. 

    #define NCLog(s, ...) NSLog(@&quot;&lt;%@:%d&gt; %@&quot;, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], \
        __LINE__, [NSString stringWithFormat:(s), ##__VA_ARGS__])

For example, when I call NCLog(@&quot;Hello world&quot;);
The output will be:

    &lt;ApplicationDelegate:10&gt;Hello world

Now I also want to log out the method name like:

    &lt;ApplicationDelegate:applicationDidFinishLaunching:10&gt;Hello world


So, this would make our debugging become easier when we can know which method is getting called. I know that we also have Xcode debugger but sometimes, I also want to do debugging by logging out.

NSLog the method name with Objective-C in iPhone

[PhoneGap][1] and [Titanium][2] allow you build native iPhone Apps based on HTML and JavaScript. 

Has anyone gained experience with both? What are the differences?


  [1]: http://www.phonegap.com/
  [2]: http://www.appcelerator.com/

PhoneGap vs. Titanium

I am compiling an IPhone application via command line (so no XCode options involved) and I am unable to get my symbol names to show when profiling with Instruments. I have tried several flags such as -gdawrf-2 and -g without any success. I have also tried using dsymutils to generate a .dSYM file but i have no clue how I&#39;m supposed to use it so that failed aswell.

Any help will be greatly appreciated!

Missing symbol names when profiling IPhone application with Instruments

I have a URL for an image (got it from UIImagePickerController) but I no longer have the image in memory (the URL was saved from a previous run of the app).  Can I reload the UIImage from the URL again?  

I see that UIImage has a imageWithContentsOfFile: but I have a URL.  Can I use NSData&#39;s dataWithContentsOfURL: to read the URL?

EDIT1
-
---
 based on @Daniel&#39;s answer I tried the following code but it doesn&#39;t work...

    NSLog(@&quot;%s %@&quot;, __PRETTY_FUNCTION__, photoURL);		
    if (photoURL) {
        NSURL* aURL = [NSURL URLWithString:photoURL];
        NSData* data = [[NSData alloc] initWithContentsOfURL:aURL];
        self.photoImage = [UIImage imageWithData:data];
        [data release];
    }

When I ran it the console shows:

    -[PhotoBox willMoveToWindow:] file://localhost/Users/gary/Library/Application%20Support/iPhone%20Simulator/3.2/Media/DCIM/100APPLE/IMG_0004.JPG
    *** -[NSURL length]: unrecognized selector sent to instance 0x536fbe0
    *** Terminating app due to uncaught exception &#39;NSInvalidArgumentException&#39;, reason: &#39;*** -[NSURL length]: unrecognized selector sent to instance 0x536fbe0&#39;

Looking at the call stack, I&#39;m calling URLWithString, which calls URLWithString:relativeToURL:, then initWithString:relativeToURL:, then _CFStringIsLegalURLString, then CFStringGetLength, then __forwarding_prep_0__, then __forwarding__, then -[NSObject doesNotRecognizeSelector].

Any ideas why my NSString (photoURL&#39;s address is 0x536fbe0) doesn&#39;t respond to length?  Why does it say it doesn&#39;t respond to -[NSURL length]?  Doesn&#39;t it know that param is an NSString, not a NSURL?

EDIT2
-
---
OK, the only problem with the code is the string to URL conversion.  If I hardcode the string, everything else works fine.  So something is wrong with my NSString and if I can&#39;t figure it out, I guess that should go in as a different question.  With this line inserted (I pasted the path from the console log above), it works fine:

    photoURL = @&quot;file://localhost/Users/gary/Library/Application%20Support/iPhone%20Simulator/3.2/Media/DCIM/100APPLE/IMG_0004.JPG&quot;;



Can I load a UIImage from a URL?

I have a `UITableView` that is populated with cells of a variable height. I would like the table to scroll to the bottom when the view is pushed into view.

I currently have the following function

    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[log count]-1 inSection:0];
    [self.table scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionBottom animated:NO];

log is a mutable array containing the objects that make up the content of each cell.

The above code works fine in `viewDidAppear` however this has the unfortunate side effect of displaying the top of the table when the view first appears and then jumping to the bottom. I would prefer it if the `table view` could be scrolled to the bottom before it appears.

I tried the scroll in `viewWillAppear` and `viewDidLoad` but in both cases the data has not been loaded into the table yet and both throw an exception.

Any guidance would be much appreciated, even if it&#39;s just a case of telling me what I have is all that is possible.

How to scroll to the bottom of a UITableView on the iPhone before the view appears

How can I get the last day of the current month as an `NSDate`?

Getting the last day of a month

I need to check if an dict has a key or not. How?

How to check if an NSDictionary or NSMutableDictionary contains a key?

I want to remove the default blue color of uitableview cell selection. I don&#39;t want any selection color there. I have not created a custom cell class. I&#39;m customizing the cell by adding labels and buttons over it. 
I tried doing:

    cell.selectioncolor = [UIColor clearcolor];

but it says that this method is deprecated.


Remove the cell highlight color of UITableView

I was using this, in Swift 1.2

    let urlwithPercentEscapes = myurlstring.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)

This now gives me a warning asking me to use

    stringByAddingPercentEncodingWithAllowedCharacters

I need to use a **NSCharacterSet** as an argument, but there are so many and I cannot determine what one will give me the same outcome as the previously used method.

**An example URL I want to use will be like this**

    http://www.mapquestapi.com/geocoding/v1/batch?key=YOUR_KEY_HERE&amp;callback=renderBatch&amp;location=Pottsville,PA&amp;location=Red Lion&amp;location=19036&amp;location=1090 N Charlotte St, Lancaster, PA

The URL Character Set for encoding seems to contain sets the trim my
URL. i.e, 
&gt; 
&gt; The path component of a URL is the component immediately following the
&gt; host component (if present). It ends wherever the query or fragment
&gt; component begins. For example, in the URL
&gt; http://www.example.com/index.php?key1=value1, the path component is
&gt; /index.php.

However I don&#39;t want to trim any aspect of it.
When I used my String, for example `myurlstring` it would fail.

But when used the following, then there were no issues. It encoded the string with some magic and I could get my URL data.

    let urlwithPercentEscapes = myurlstring.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)

As it

&gt; Returns a representation of the String using a given encoding to
&gt; determine the percent escapes necessary to convert the String into a
&gt; legal URL string

Thanks

How to use stringByAddingPercentEncodingWithAllowedCharacters() for a URL in Swift 2.0

I have the need to parse some unknown data which should just be a numeric value, but may contain whitespace or other non-alphanumeric characters.

Is there a new way of doing this in Swift? All I can find online seems to be the old C way of doing things. 

I am looking at `stringByTrimmingCharactersInSet` - as I am sure my inputs will only have whitespace/special characters at the start or end of the string. Are there any built in character sets I can use for this? Or do I need to create my own?

I was hoping there would be something like `stringFromCharactersInSet()` which would allow me to specify only valid characters to keep

Content Type	Original Author	Original Content on Stackoverflow
Question	typeoneerror	View Question on Stackoverflow
Solution 1 - Iphone	drawnonward	View Answer on Stackoverflow
Solution 2 - Iphone	Russ Van Bert	View Answer on Stackoverflow
Solution 3 - Iphone	AsbelK	View Answer on Stackoverflow

NSCharacterSet: How do I add "_" to alphanumericCharacterSet text restriction?

Iphone Problem Overview

Iphone Solutions

Solution 1 - Iphone

Solution 2 - Iphone

Solution 3 - Iphone

How does jQuery .data() work?

Waiting on multiple asynchronous calls to complete before continuing

Attributions