The parameters for your completionHandler closure are reversed, they should be:

    (home: HMHome!, error: NSError!)

Also note that you don&#39;t need to specify the types for the parameters, since the method signature specified them for you - thus you can simply list the parameter names you want to use, and they will automatically be assured to be of the correct type, for example:

    homeManager.addHomeWithName(&quot;My House&quot;, completionHandler:{
        home, error in
        if error { NSLog(&quot;%@&quot;, error) }
        })

--_edit_--

Also note that when I wrote _&#39;you can simply list the parameter names you want to use, and they will automatically be assured to be of the correct type&#39;_, that is to say that they will be typed according to the order in which they are listed - e.g. if you had used `error, home in` instead, then those would be your parameter names however the parameter `error` would be of type `HMHome!`, and `home` would be of type `NSError!` (since that is the order in which they appear in the parameter list for the closure in the method&#39;s signature)

Your arguments are ordered inconsistently; the signature for the `completionHandler` in `addHomeWithName` is 

    (HMHome!, NSError!) -&gt; Void

thus use:

    homeManager.addHomeWithName (&quot;My House&quot;, completionHandler:
      { (home: HMHome!, error: NSError!) in
          if error { NSLog(&quot;%@&quot;, error) }} )

Using a trailing closure and allowing the compiler to infer the types lets you simplify the above to:

    homeManager.addHomeWithName (&quot;My House&quot;) {
      if $1 { NSLog (&quot;%@&quot;, $1) }
    }

I am practicing JavaScript on Chrome&#39;s &#39;JavaScript Console&#39; ( version: 35.0) and I am unable to use the &#39;use strict&#39; clause as expected.

For the following code snippet :

    var obj={x:1,y:2}
    
    //Define new property with &#39;writable&#39; flag as false.
    Object.defineProperty(obj, &quot;z&quot;, {value:3, writable:false, enumerable:false, configurable:false})
    
    // Try to change the property &#39;z&#39;,
    &quot;use strict&quot;; obj[&quot;z&quot;]=4

&gt; Output: 4

As per my understanding, changing value of a &#39;non-writable&#39; property will silently fail in non-strict mode and throw &#39;TypeError&#39; in strict mode, But I don&#39;t see the exception.

    console.log(obj)

&gt; Object {x: 1, y: 2, z: 3}

Even though the property value is not changed but I am expecting a exception. 
Please correct if I am doing something wrong ?

How to use &#39;strict&#39; mode in Chrome &#39;JavaScript Console&#39;

I got an error using ASP.NET Identity in my app. 

&gt; Multiple object sets per type are not supported. The object sets
&gt; &#39;Identity Users&#39; and &#39;Users&#39; can both contain instances of type
&gt; &#39;Recommendation Platform.Models.ApplicationUser&#39;.

I saw a few questions about this error in StackOverflow. All indicate on two `DbSet` objects of the same type. But in my `DbContext` there aren&#39;t the same types of `DbSets`. Exception is thrown on `FindAsync()` method during logging in. 

    if (ModelState.IsValid)
        var user = await UserManager.FindAsync(model.UserName, model.Password);
        if (user != null &amp;&amp; user.IsConfirmed)
        {

The problem is I don&#39;t have two `DbSets` of the same type. My Contexts look like this:

    public class ApplicationDbContext : IdentityDbContext&lt;ApplicationUser&gt;
    {
        public ApplicationDbContext()
            : base(&quot;DefaultConnection&quot;)
        {
        }

        public System.Data.Entity.DbSet&lt;RecommendationPlatform.Models.ApplicationUser&gt; IdentityUsers { get; set; }

    }

and

    public class RecContext : DbContext
    {
        public RecContext()
            : base(&quot;RecConnection&quot;)
        {
            Database.SetInitializer&lt;RecContext&gt;(new DropCreateDatabaseIfModelChanges&lt;RecContext&gt;());
        }

        public DbSet&lt;Recommendation&gt; Recommendations { get; set; }
        public DbSet&lt;Geolocation&gt; Geolocations { get; set; }
        public DbSet&lt;Faq&gt; Faqs { get; set; }
        public DbSet&lt;IndexText&gt; IndexTexts { get; set; }
    }

What could cause this problem? Maybe something connected with in-built ASP.NET Identity functionalities? Anyway, what is `Users` type? I don&#39;t have it in my app...

ASP.NET Identity - Multiple object sets per type are not supported

I&#39;m playing with HomeKit, and I&#39;m trying to add a new home. This is my code:

    func addHome()
    {
        homeManager.addHomeWithName(&quot;My House&quot;, completionHandler:
            { (error: NSError!, home: HMHome!) in
                if error
                {
                    NSLog(&quot;%@&quot;, error)
                }
            })
    }

This gives a compiler error:

&gt;     Cannot convert the expression&#39;s type &#39;Void&#39; to type &#39;String!&#39;

I&#39;ve tried specifying a return type of `Void`: 

    ...
    { (error: NSError!, home: HMHome!) -&gt; Void in
    ...

to no avail. Does anyone have any ideas how to fix this? Passing `nil` to the completion handler fixes the error, but of course I want to do something on completion.

HomeKit completion block in Swift: Cannot convert the expression&#39;s type &#39;Void&#39; to type &#39;String!&#39;

I'm playing with HomeKit, and I'm trying to add a new home. This is my code:
<pre><code class="hljs language-go">func addHome()
{
 homeManager.addHomeWithName("My House", completionHandler:
 { (error: NSError!, home: HMHome!) in
 if error
 {
 NSLog("%@", error)
 }
 })
}
</code></pre>
This gives a compiler error:
> Cannot convert the expression's type 'Void' to type 'String!'
I've tried specifying a return type of <code>Void</code>:
<pre><code class="hljs language-python-repl">...
{ (error: NSError!, home: HMHome!) -> Void in
...
</code></pre>
to no avail. Does anyone have any ideas how to fix this? Passing <code>nil</code> to the completion handler fixes the error, but of course I want to do something on completion.

`label.font.pointSize` is read-only, so I&#39;m not sure how to change it.

How do I change the font size of a UILabel in Swift?

I am adding `UIPickerView` to `UIActionsheet` but its working perfectally in `ios 7` but not working in `ios 8`. Please help me to solve that.

Here i attached screenshot for that.![enter image description here][1]

Thanks


  [1]: http://i.stack.imgur.com/sBtn5.png


I am using following code for that.

    UIActionSheet *actionSheet;
    NSString *pickerType;
    
    - (void)createActionSheet {
        
        if (actionSheet == nil) {
            // setup actionsheet to contain the UIPicker
            actionSheet = [[UIActionSheet alloc] initWithTitle:@&quot;Please select&quot; delegate:self cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil];
            actionSheet.backgroundColor = [UIColor clearColor];
    
            UIToolbar *pickerToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 320, 40)];
            pickerToolbar.barStyle = UIBarStyleBlackOpaque;
            [pickerToolbar sizeToFit];
            
            UIImageView *imageObj = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
            imageObj.image = [UIImage imageNamed:@&quot;header.png&quot;];
            [pickerToolbar addSubview:imageObj];
            
            UIButton *cancelBtn = [UIButton buttonWithType:UIButtonTypeCustom];
            [cancelBtn addTarget:self action:@selector(pickerCancel:)forControlEvents:UIControlEventTouchDown];
            // [cancelBtn setImage:[UIImage imageNamed:@&quot;btnInviteCancel.png&quot;] forState:UIControlStateNormal];
            [cancelBtn setTitle:@&quot;Cancel&quot; forState:UIControlStateNormal];
            
            cancelBtn.frame = CGRectMake(7.0, 7.0, 65.0, 25.0);
            [pickerToolbar addSubview:cancelBtn];
            
            UIButton *doneBtn = [UIButton buttonWithType:UIButtonTypeCustom];
            [doneBtn addTarget:self action:@selector(pickerDone:)forControlEvents:UIControlEventTouchDown];
            //[doneBtn setImage:[UIImage imageNamed:@&quot;btnInviteDone.png&quot;] forState:UIControlStateNormal];
            [doneBtn setTitle:@&quot;Done&quot; forState:UIControlStateNormal];
            doneBtn.frame = CGRectMake(258.0, 7.0, 55.0, 25.0);
            [pickerToolbar addSubview:doneBtn];
            
            [actionSheet addSubview:pickerToolbar];
            [pickerToolbar release];
            
            
            UIPickerView *chPicker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 200.0)];
            chPicker.dataSource = self;
            chPicker.delegate = self;
            chPicker.showsSelectionIndicator = YES;
            [chPicker selectRow:0 inComponent:0 animated:YES];
            [actionSheet addSubview:chPicker];
            [chPicker release];
            
            [actionSheet showInView:self.view];
            [actionSheet setBounds:CGRectMake(0,0,320, 464)];
        }
    }



Add UIPickerView in UIActionSheet from IOS 8 not working

I have a RESTFull service with basic authentication and I want to invoke it from iOS+swift. How and where I must provide Credential for this request?

My code (sorry, I just start learn iOS/obj-c/swift):

```
class APIProxy: NSObject {
    var data: NSMutableData = NSMutableData()
    
    func connectToWebApi() {
        var urlPath = &quot;http://xx.xx.xx.xx/BP3_0_32/ru/hs/testservis/somemethod&quot;
        NSLog(&quot;connection string \(urlPath)&quot;)
        var url: NSURL = NSURL(string: urlPath)
        var request = NSMutableURLRequest(URL: url)
        let username = &quot;hs&quot;
        let password = &quot;1&quot;
        let loginString = NSString(format: &quot;%@:%@&quot;, username, password)
        let loginData: NSData = loginString.dataUsingEncoding(NSUTF8StringEncoding)
        let base64LoginString = loginData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.fromMask(0))
        request.setValue(base64LoginString, forHTTPHeaderField: &quot;Authorization&quot;)
        
        var connection: NSURLConnection = NSURLConnection(request: request, delegate: self)
        
        connection.start()
    }
    
    
    //NSURLConnection delegate method
    func connection(connection: NSURLConnection!, didFailWithError error: NSError!) {
        println(&quot;Failed with error:\(error.localizedDescription)&quot;)
    }
    
    //NSURLConnection delegate method
    func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
        //New request so we need to clear the data object
        self.data = NSMutableData()
    }
    
    //NSURLConnection delegate method
    func connection(connection: NSURLConnection!, didReceiveData data: NSData!) {
        //Append incoming data
        self.data.appendData(data)
    }
    
    //NSURLConnection delegate method
    func connectionDidFinishLoading(connection: NSURLConnection!) {
        NSLog(&quot;connectionDidFinishLoading&quot;);
    }
    
}
```

How to make an HTTP request + basic auth in Swift

I&#39;m trying to apply a gradient as the background color of a View (main view of a storyboard). The code runs, but nothing changes. I&#39;m using xCode Beta 2 and Swift.

Here&#39;s the code:


    class Colors {
      let colorTop = UIColor(red: 192.0/255.0, green: 38.0/255.0, blue: 42.0/255.0, alpha: 1.0)
      let colorBottom = UIColor(red: 35.0/255.0, green: 2.0/255.0, blue: 2.0/255.0, alpha: 1.0)
    
      let gl: CAGradientLayer

      init() {
        gl = CAGradientLayer()
        gl.colors = [ colorTop, colorBottom]
        gl.locations = [ 0.0, 1.0]
      }
    }

then in the view controller:

      let colors = Colors()
      
      func refresh() {
            view.backgroundColor = UIColor.clearColor()
            var backgroundLayer = colors.gl
            backgroundLayer.frame = view.frame
            view.layer.insertSublayer(backgroundLayer, atIndex: 0)
          }
        }
      }



How to Apply Gradient to background view of iOS Swift App

I&#39;m trying to play a sound with `AVAudioPlayer` but it won&#39;t work.

**Edit 1:** Still doesn&#39;t work.

**Edit 2**: This code works. My device was in silent mode.
    
    import UIKit
    import AVFoundation

    class ViewController: UIViewController {
    
        var audioPlayer = AVAudioPlayer()
                            
        override func viewDidLoad() {
            super.viewDidLoad()
        
            var alertSound = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource(&quot;button-09&quot;, ofType: &quot;wav&quot;))
            println(alertSound)
        
            var error:NSError?
            audioPlayer = AVAudioPlayer(contentsOfURL: alertSound, error: &amp;error)
            audioPlayer.prepareToPlay()
            audioPlayer.play()
        }
    }


Playing a sound with AVAudioPlayer

In Objective-C, you can define a block&#39;s input and output, store one of those blocks that&#39;s passed in to a method, then use that block later:

    // in .h

		typedef void (^APLCalibrationProgressHandler)(float percentComplete);
		typedef void (^APLCalibrationCompletionHandler)(NSInteger measuredPower, NSError *error);

		// in .m

		@property (strong) APLCalibrationProgressHandler progressHandler;
		@property (strong) APLCalibrationCompletionHandler completionHandler;

		- (id)initWithRegion:(CLBeaconRegion *)region completionHandler:(APLCalibrationCompletionHandler)handler
		{
		    self = [super init];
		    if(self)
		    {
		        ...
		        _completionHandler = [handler copy];
		        ..
		    }
    
		    return self;
	}

	- (void)performCalibrationWithProgressHandler:(APLCalibrationProgressHandler)handler
	{
	    ...
           
	            self.progressHandler = [handler copy];
            
	     ...
	            dispatch_async(dispatch_get_main_queue(), ^{
	                _completionHandler(0, error);
	            });
	     ...
	}

So I&#39;m trying to do the equivilant in Swift:

    var completionHandler:(Float)-&gt;Void={}
   
    
    init() {
        locationManager = CLLocationManager()
        region = CLBeaconRegion()
        timer = NSTimer()
    }
    
    convenience init(region: CLBeaconRegion, handler:((Float)-&gt;Void)) {
        self.init()
        locationManager.delegate = self
        self.region = region
        completionHandler = handler
        rangedBeacons = NSMutableArray()
    }

The compiler doesn&#39;t like that declaration of completionHandler. Not that I blame it, but, how do I define a closure that can be set and used later in Swift?



Store a closure as a variable in Swift

For the following code:

    for sort_key, order in query_data[&#39;sort&#39;]:
        results.sort(key=lambda k: get_from_dot_path(k, sort_key),
                     reverse=(order == -1))

Pylint reported an error: 

&gt; Cell variable sort_key defined in loop (cell-var-from-loop)

Could anyone give a hint what is happening here? From pylint source code the description is:

&gt; A variable used in a closure is defined in a loop.
&gt; This will result in all closures using the same value for
&gt; the closed-over variable.

But I do not have a clue what it means. Could anyone give an example of the problem?

Cell-var-from-loop warning from Pylint

I&#39;m studying [THREE.js][1] and noticed a pattern where functions are defined like so:

    var foo = ( function () {
    	var bar = new Bar();
    
    	return function ( ) {
    		//actual logic using bar from above.
    		//return result;
    	};
    }());


(Example see raycast method [here](https://github.com/mrdoob/three.js/blob/master/src/objects/Sprite.js)).

The _normal_ variation of such a method would look like this:

    var foo = function () {
    	var bar = new Bar();
    
    	//actual logic.
    	//return result;
    };


Comparing the first version to the _normal_ variation, the first seems to differ in that:

  1. It assigns the result of a self-executing function.
  3. It defines a local variable within this function.
  2. It returns the _actual_ function containing logic that makes use of the local variable.

So the main difference is that in the first variation the bar is only assigned once, at initialization, while the second variation creates this temporary variable every time it is called.

My best guess on why this is used is that it limits the number of instances for bar (there will only be one) and thus saves memory management overhead.

My questions:

  1. Is this assumption correct?
  1. Is there a name for this pattern?
  1. Why is this used?


  [1]: http://threejs.org/

What is this JavaScript pattern called and why is it used?

So what I want to have is a class that may get a closure passed to it in a function, it may also at some point want to disregard a that closure. How can I check if the closure variable is set and hwo can I delete it when I am done with it?
 

&gt; Cannot invoke &#39;!=&#39; with an argument list of type &#39;(@lvalue (sucsess:
&gt; Bool!, products: [AnyObject]!) -&gt; ()?, NilLiteralConvertible)&#39; Type
&gt; &#39;(sucsess: Bool!, products: [AnyObject]!) -&gt; ()?&#39; does not conform to
&gt; protocol &#39;NilLiteralConvertible&#39;

 
 

    class someClass{
        //typealias completionHandlerClosureType = (sucsess:Bool!, items:[AnyObject]!)-&gt;()
        var completionHandler:(sucsess:Bool!, items:[AnyObject]!)-&gt;()?
        var hitpoints = 100
        var someset = [&quot;oh no!&quot;,&quot;avenge me!&quot;]
        init(){}
    
        func getHitFunc(impact:Int, passedCompletionsHandler:(sucsess:Bool!, items:[AnyObject]!)-&gt;()){
            completionHandler = passedCompletionsHandler
            hitpoints = hitpoints - impact
        }
        
        func checkIfDead{
            if hitpoints&lt;=0 {               // The error received
                if completionHandler != nil{// Cannot invoke &#39;!=&#39; with an argument list of type 
                                            //&#39;(@lvalue (sucsess: Bool!, products: [AnyObject]!) -&gt; ()?, NilLiteralConvertible)&#39; 
                    //run the handler if dead
                    completionHandler(sucsess: true, items: someset)
                    //do not run it again
                    completionHandler = nil     //Type &#39;(sucsess: Bool!, products: [AnyObject]!) -&gt; ()?&#39; does not conform to protocol &#39;NilLiteralConvertible&#39;
                }
            }
            else{
                completionHandler = nil      //Type &#39;(sucsess: Bool!, products: [AnyObject]!) -&gt; ()?&#39; does not conform to protocol &#39;NilLiteralConvertible&#39;
            }
        }
    }



optional closure and check if it is nil

A 3rd party library we use contains a rather long function that uses a nested function inside it. Our use of that library triggers a bug in that function, and we very much would like to solve that bug.

Unfortunately, the library maintainers are somewhat slow with fixes, but we don&#39;t want to have to fork the library. We also cannot hold our release until they have fixed the issue.

We would prefer to use monkey-patching to fix this issue here as that is easier to track than patching the source. However, to repeat a very large function where just replacing the inner function would be enough feels overkill, and makes it harder for others to see what exactly we changed. Are we stuck with a static patch to the library egg?

The inner function relies on closing over a variable; a contrived example would be:

    def outerfunction(*args):
        def innerfunction(val):
            return someformat.format(val)

        someformat = &#39;Foo: {}&#39;
        for arg in args:
            yield innerfunction(arg)

where we would want to replace just the implementation of `innerfunction()`. The actual outer function is far, far longer. We&#39;d reuse the closed-over variable and maintain the function signature, of course.

Can you patch *just* a nested function with closure, or must the whole outer function be repeated?

In Objective-C we use to do it like this

    + (Class)layerClass
    {
        return [CAEAGLLayer class];
    }

Obviously this won&#39;t work:

    CAEAGLLayer.class()

Because `class` is a keyword in Swift. How do you do it in Swift?

How do you override layerClass in swift

Which is the equivalent of `isnan()` in Swift ? 
I need to check if some operation results are valid and delete those invalid like x/0
Thanks

Which is the Swift equivalent of isnan()?

in objective c it can be done in init method by


    -(id)init{
        self = [[[NSBundle mainBundle] loadNibNamed:@&quot;ViewBtnWishList&quot; owner:0 options:nil]     objectAtIndex:0];
    return self;
    }

but when i do this in swift

    init(frame: CGRect) {
        self = NSBundle.mainBundle().loadNibNamed(&quot;ViewDetailMenu&quot;, owner: 0, options: nil)[0] as? UIView
    }

cannot assign to self in a method error is shown.
now my approach is to create a view, and add the view loaded from nib to it.
anyone have a better idea?

Assign xib to the UIView in Swift

Is there a way to work with reverse ranges in Swift?

For example:

    for i in 5...1 {
      // do something
    }

is an infinite loop.

In newer versions of Swift that code compiles, but at runtime gives the error: 

 &gt; Fatal error: Can&#39;t form Range with upperBound &lt; lowerBound

I know I can use `1..5` instead, calculate `j = 6 - i` and use `j` as my index. I was just wondering if there was anything more legible?


Content Type	Original Author	Original Content on Stackoverflow
Question	SmokeDetector	View Question on Stackoverflow
Solution 1 - Ios	fqdn	View Answer on Stackoverflow
Solution 2 - Ios	GoZoner	View Answer on Stackoverflow

HomeKit completion block in Swift: Cannot convert the expression's type 'Void' to type 'String!'

Ios Problem Overview

Ios Solutions

Solution 1 - Ios

Solution 2 - Ios

ASP.NET Identity - Multiple object sets per type are not supported

How to use 'strict' mode in Chrome 'JavaScript Console'

Attributions