    // Original answer.
    var newColor = UIColor.lightGrayColor().CGColor

    // Swift 3 version
    var newColor = UIColor.lightGray.cgColor

Oddly enough, as Swift has evolved to 3.0 the answer has evolved as well. I ran across this while converting some Objective C code to Swift.  I hope this helps someone! :-) Here is what it is today:

    context.setStrokeColor(UIColor.lightGray.cgColor)

And it&#39;s funny, this &quot;light gray&quot; answer is actually helping me debug some code too!  Thank iou!

Swift 4+ version    


    UIColor.lightGray.cgColor

In a simple example like this one, the child margin does not affect parent height:

&lt;!-- begin snippet: js hide: false console: false babel: false --&gt;

&lt;!-- language: lang-css --&gt;

    .parent{ background: 
        black; 
    }
    .child{
        background: LightBlue;
        margin: 20px;
    }

&lt;!-- language: lang-html --&gt;

    &lt;div class=&quot;parent&quot;&gt;
        &lt;div class=&quot;child&quot;&gt;Some text...&lt;/div&gt;
    &lt;/div&gt;

&lt;!-- end snippet --&gt;

JSFiddle: http://jsfiddle.net/k1eegxt3/

By default, child margins do not affect parent height respectively parent dimensions in general, it is easily **fixed by adding something that margin could &quot;push&quot; to** in parent element, e.g. **add a padding or border to parent.:**

```css
.parent{ background: 
    black;
    padding: 1px; /* PADDING ADDED */ 
}
.child{
    background: LightBlue;
    margin: 20px;
}
```

JSFiddle: http://jsfiddle.net/fej3qh0z/

I want to know _why_ this works this way, not just how it is fixed.

Can someone explain, ideally with a reference to the specification, why this works this way?

Why doesn&#39;t a child&#39;s margin affect a parent&#39;s height?

Let&#39;s say I have a protocol :

    public protocol Printable {
        typealias T
        func Print(val:T)
    }

And here is the implementation 

    class Printer&lt;T&gt; : Printable {
        
        func Print(val: T) {
            println(val)
        }
    }

My expectation was that I must be able to use `Printable` variable to print values like this :

    let p:Printable = Printer&lt;Int&gt;()
    p.Print(67)

Compiler is complaining with this error : 

&gt; &quot;protocol &#39;Printable&#39; can only be used as a generic constraint because
&gt; it has Self or associated type requirements&quot;

Am I doing something wrong ? Anyway to fix this ?


    **EDIT :** Adding similar code that works in C#
    
    public interface IPrintable&lt;T&gt; 
    {
        void Print(T val);
    }
    
    public class Printer&lt;T&gt; : IPrintable&lt;T&gt;
    {
       public void Print(T val)
       {
          Console.WriteLine(val);
       }
    }
    
    
    //.... inside Main
    .....
    IPrintable&lt;int&gt; p = new Printer&lt;int&gt;();
    p.Print(67)


EDIT 2: Real world example of what I want. Note that this will not compile, but presents what I want to achieve.

    protocol Printable 
    {
       func Print()
    }
    
    protocol CollectionType&lt;T where T:Printable&gt; : SequenceType 
    {
       .....
       /// here goes implementation
       ..... 
    }
    
    public class Collection&lt;T where T:Printable&gt; : CollectionType&lt;T&gt;
    {
        ......
    }
    
    let col:CollectionType&lt;Int&gt; = SomeFunctiionThatReturnsIntCollection()
    for item in col {
       item.Print()
    }

How to use generic protocol as a variable type

This is the Obj-C code:

    CGContextSetStrokeColorWithColor(context, [[UIColor lightGrayColor] CGColor]);

How do I write it in swift.

Converting UIColor to CGColor in swift

This is the Obj-C code:
<pre><code class="hljs language-objectivec">CGContextSetStrokeColorWithColor(context, [[UIColor lightGrayColor] CGColor]);
</code></pre>
How do I write it in swift.

I have an auto-generated clear button on my UITextfield, with the default blue tint color. I cannot change the tint color to white. I have tried modifying the storyboard and code without success, and I do not want to use a custom image.

How can I change the default clear button tint color without using a custom image?

![clicked][1]

  [1]: http://i.stack.imgur.com/oezUP.png

How to change the tint color of the clear button on a UITextField

I have a searchBar I&#39;m setting in a tableviewcontroller. i&#39;ve referenced this similar question https://stackoverflow.com/questions/27451088/uisearchbar-cannot-become-first-responder-after-uitableview-did-re-appear but am still unable to set it as first responder. 
In .h file:

    @property (strong, nonatomic) UISearchController *searchController;
    @property (strong, nonatomic) IBOutlet UISearchBar *searchBar;

In view didload:
 

    self.searchController = [[UISearchController alloc]initWithSearchResultsController:nil];
    self.searchController.searchResultsUpdater = self;
    self.searchController.dimsBackgroundDuringPresentation = NO;
    self.searchController.hidesNavigationBarDuringPresentation = NO;
        
    self.searchController.searchBar.frame = CGRectMake(self.searchController.searchBar.frame.origin.x, self.searchController.searchBar.frame.origin.y, self.searchController.searchBar.frame.size.width, 44.0);
    self.tableView.tableHeaderView = self.searchController.searchBar;

And in viewDidAppear:

    -(void)viewDidAppear:(BOOL)animated {
      [self.searchController setActive:YES];
      [self.searchController.searchBar becomeFirstResponder];
      [super viewDidAppear:animated];
    }

When I segue to the view the searchBar animates, but no keyboard appears.

Cannot set searchBar as firstResponder

I&#39;ve been trying to checkout CocoaPods new framework setup to get some Pods going and I&#39;m having trouble using the Swift one&#39;s in my Objective-C project.

First things first, this is CocoaPods prerelease 0.35, you can read about how to use and install it &lt;a href=&quot;http://blog.cocoapods.org/Pod-Authors-Guide-to-CocoaPods-Frameworks/&quot;&gt;here&lt;/a&gt;.

Here&#39;s my current Podfile:

    source &#39;https://github.com/CocoaPods/Specs.git&#39;
    
    platform :ios, &#39;8.0&#39;
    
    pod &#39;MBProgressHUD&#39;
    pod &#39;SLPagingViewSwift&#39;

MBProgressHUD is a common spinning indicator, and SLPagingViewSwift is a random project I found by typing Swift into the cocoapods search.  Here&#39;s the `ViewController.m` In my project:

    #import &quot;ViewController.h&quot;
    
    @import SLPagingViewSwift;
    @import MBProgressHUD;
    
    @interface ViewController ()
    
    @end
    
    @implementation ViewController
    
    - (void)viewDidAppear:(BOOL)animated
    {
        [super viewDidAppear:animated];
        
        // Works just fine
        MBProgressHUD *hud = [[MBProgressHUD alloc] initWithView:self.view];
        [self.view addSubview:hud];
        [hud show:YES];

        // Causes Error -- Won&#39;t build
        SLPagingViewSwift *sl = [[SLPagingViewSwift alloc] init];
    }
    
    @end


Here&#39;s the `SLPagingViewSwift` declaration:

    class SLPagingViewSwift: UIViewController, UIScrollViewDelegate {

As you can see, it inherits from `UIViewController`, so it shouldn&#39;t be a problem to just allocate it and initialize it.  If I add the file separately as just a file, the above code runs just fine.  I know it works.

&lt;b&gt; tl;dr &lt;/b&gt;

How can I use a pure Swift Framework created by CocoaPods in a pure Objective-C class?

&lt;b&gt; TroubleShooting &lt;/b&gt;

Mostly I&#39;ve been trying various imports.  Apple recommends the `@import` style &lt;a href=&quot;https://developer.apple.com/library/ios/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html#//apple_ref/doc/uid/TP40014216-CH10-XID_77&quot;&gt;here&lt;/a&gt;

![enter image description here][1]

But I have been trying multiple other varieties:

    // Compiler Error
    #import &lt;SLPagingViewSwift/SLPagingViewSwift.h&gt;
    
    // Builds Fine -- Doesn&#39;t Work
    #import &lt;SLPagingViewSwift/SLPagingViewSwift-Swift.h&gt;
    #import &quot;SLPagingViewSwift-Swift.h&quot;

I&#39;ve also been trying a few other Swift libraries from time to time to see if I could make anything click.

I don&#39;t see anything on the Cocoapods issues that can help this, I also didn&#39;t find anything in their blog / release stuff.

&lt;b&gt; Note &lt;/b&gt;

If I add the `SLPagingViewSwift.swift` file separately to the project the old fashioned way, it works just fine.

  [1]: http://i.stack.imgur.com/G1EJc.png

How to import and use Swift Pod Framework in Objective-C Project

I&#39;m using an image view to display an image in my nav bar. The problem is that I can&#39;t set it to the center correctly because of the back button. I checked the related questions and had almost the same problem earlier that I solved, but this time I have no idea.

Earlier I solved this problem with fake bar buttons, so I tried to add a fake bar button to the right (and left) side, but it doesn&#39;t helped. 

    - (void) searchButtonNavBar {
        
        
        CGRect imageSizeDummy = CGRectMake(0, 0, 25,25);
        
        UIButton *dummy = [[UIButton alloc] initWithFrame:imageSizeDummy];
        
        UIBarButtonItem
        *searchBarButtonDummy =[[UIBarButtonItem alloc] initWithCustomView:dummy];
        self.navigationItem.rightBarButtonItem = searchBarButtonDummy;
      
    }


    - (void)setNavBarLogo {
        
        [self setNeedsStatusBarAppearanceUpdate];
        CGRect myImageS = CGRectMake(0, 0, 44, 44);
        UIImageView *logo = [[UIImageView alloc] initWithFrame:myImageS];
        [logo setImage:[UIImage imageNamed:@&quot;color.png&quot;]];
        logo.contentMode = UIViewContentModeScaleAspectFit;
        self.navigationItem.titleView = logo;
        [[UIBarButtonItem appearance] setTitlePositionAdjustment:UIOffsetMake(0.0f, 0.0f) forBarMetrics:UIBarMetricsDefault];
        
    }
I think it should be workin fine because in this case the `titleView` has bar buttons on the same side. Is there any explanation why it worked with bar buttons that was created programmatically but doesn&#39;t works with the common back button?
	



Can&#39;t set titleView in the center of navigation bar because back button

I&#39;m making test application, so in my tableviewCell in storyboard I have **imageView** &amp; **webView** (webview to show html-text). 

I set constraints like top/left/right/height=200 for **imageView**, spacing=5 between them &amp; left/right/bot for **webView**, so I want to calculate my **webView** height programmatically and then change cell&#39;s height to stretch my **webView**. But I got this :

    Unable to simultaneously satisfy constraints.
    
    Probably at least one of the constraints in the following list is one you don&#39;t want.
    
    Try this:
    
        (1) look at each constraint and try to figure out which you don&#39;t expect;
        (2) find the code that added the unwanted constraint or constraints &amp; fix it. (Note: If you&#39;re seeing NSAutoresizingMaskLayoutConstraints that you don&#39;t understand, refer to the documentation for the UIView property
    
        translatesAutoresizingMaskIntoConstraints) 
        (
            &quot;&lt;NSLayoutConstraint:0x7fd6f3773f90 V:[UIImageView:0x7fd6f3773e90(200)]&gt;&quot;,
            &quot;&lt;NSLayoutConstraint:0x7fd6f3774280 UIImageView:0x7fd6f3773e90.top == UITableViewCellContentView:0x7fd6f3462710.topMargin&gt;&quot;,
            &quot;&lt;NSLayoutConstraint:0x7fd6f3774320 V:[UIImageView:0x7fd6f3773e90]-(5)-[UIWebView:0x7fd6f3462800]&gt;&quot;,
            &quot;&lt;NSLayoutConstraint:0x7fd6f3774370 UITableViewCellContentView:0x7fd6f3462710.bottomMargin == UIWebView:0x7fd6f3462800.bottom&gt;&quot;,
            &quot;&lt;NSLayoutConstraint:0x7fd6f375ee40 &#39;UIView-Encapsulated-Layout-Height&#39; V:[UITableViewCellContentView:0x7fd6f3462710(205)]&gt;&quot;
        )

Any suggestions?

Strange UIView-Encapsulated-Layout-Height Error

I&#39;m trying to implement a table view with scrollable horizontal items (with unknown number of items) like the illustration below:

![enter image description here][1]

The UI should behave like so:

 1. At the init state the table cell shows a label and some text and the circle item pops out of the right side
 2. If the users swipes from right to left, the label and text fades out and the horizontal list (inside the cell) takes it&#39;s place


----------
I thought about using TableView and `dequeueReusableCellWithIdentifier` and creating a prototype cell, but then I need to remember the list horizontal position and init the cell properly on `cellForRowAtIndexPath` and that will probably affect performance.

**Q:** What layout would you use in order to achieve this goal, any input / tutorial would be appreciated  

  [1]: http://i.stack.imgur.com/TmiPn.jpg

IOS - How to create TableView with horizontal scrollable lists

how is it possible to send a POST request with a simple string in the HTTP body with Alamofire in my iOS app?

As default Alamofire needs parameters for a request:


    Alamofire.request(.POST, &quot;http://mywebsite.com/post-request&quot;, parameters: [&quot;foo&quot;: &quot;bar&quot;])

These parameters contain key-value-pairs. But I don&#39;t want to send a request with a key-value string in the HTTP body.

I mean something like this:

    Alamofire.request(.POST, &quot;http://mywebsite.com/post-request&quot;, body: &quot;myBodyString&quot;)

POST request with a simple string in body with Alamofire

In Objective-C such line

    self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame)/4.0f;


does its job, I tried it in Swift using analogy

    self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame)/4.0


and it doesn&#39;t change anything, the corners are the same as before. Moreover, Xcode does not show any syntax errors. Does Swift support any other way to reach this goal? I checked some other threads here and usually it&#39;s getting done in Swift in the way showed above. 

    

How to set corner radius of imageView?

While playing in a Swift playground I noticed that `Self`, with capital &quot;S&quot;, is available along with the lowercase `self`. Is there any difference between them? If so, what are usages for these two, especially for `Self`?

Distinction in Swift between uppercase &quot;Self&quot; and lowercase &quot;self&quot;

Is there no easy way to remove a specific element from an array, if it is equal to a given string? The workarounds are to find the index of the element of the array you wish to remove, and then `removeAtIndex`, or to create a new array where you append all elements that are not equal to the given string. But is there no quicker way?

Remove Specific Array Element, Equal to String - Swift

In my app I need to change the bottom navigation bar color. I watched many post but cant find with the solution. I am using appCompat library.

![enter image description here][1]


  [1]: http://i.stack.imgur.com/B8ph4.png


v21/styles.xml

    &lt;style name=&quot;AppTheme&quot; parent=&quot;Theme.AppCompat.Light&quot;&gt;
           &lt;item name=&quot;android:windowBackground&quot;&gt;@drawable/bgpreview&lt;/item&gt;
           &lt;item name=&quot;android:colorPrimary&quot;&gt;@color/MyColor&lt;/item&gt;
           &lt;item name=&quot;android:colorPrimaryDark&quot;&gt;@color/MyColor&lt;/item&gt;
           &lt;item name=&quot;android:windowContentOverlay&quot;&gt;@null&lt;/item&gt;
           &lt;item name=&quot;android:textColorPrimary&quot;&gt;@color/MyColor&lt;/item&gt;
           &lt;item name=&quot;colorAccent&quot;&gt;@color/MyColor&lt;/item&gt;
           &lt;!-- darker variant for the status bar and contextual app bars --&gt;
           &lt;item name=&quot;android:windowContentTransitions&quot;&gt;true&lt;/item&gt;
           &lt;item name=&quot;android:windowAllowEnterTransitionOverlap&quot;&gt;true&lt;/item&gt;
           &lt;item name=&quot;android:windowAllowReturnTransitionOverlap&quot;&gt;true&lt;/item&gt;
           &lt;item name=&quot;android:windowSharedElementEnterTransition&quot;&gt;@android:transition/move&lt;/item&gt;
           &lt;item name=&quot;android:windowSharedElementExitTransition&quot;&gt;@android:transition/move&lt;/item&gt;

           &lt;item name=&quot;windowActionBar&quot;&gt;false&lt;/item&gt;
           &lt;item name=&quot;android:textAllCaps&quot;&gt;false&lt;/item&gt;

    &lt;/style&gt;

Android lollipop change navigation bar color

I&#39;ve tried using the following link to change the color of a SwitchCompat:

https://stackoverflow.com/questions/26714864/how-to-change-the-color-of-a-switchcompat

Notice the low constrast in my switch:

![The SwitchCompat](http://i.imgur.com/m9zAcrp.png)

But after changing all relevant color values the track (the brighter grey) of the SwitchCompat remains the same. I don&#39;t want to change the appearance except the color. The thumb is in pink, and I want the track to have some contrast. Did I miss to define a value in my styles.xml?

I tried these values (random non-white colors):

    &lt;style name=&quot;AppTheme&quot; parent=&quot;Theme.AppCompat.Light.NoActionBar&quot;&gt;
        &lt;item name=&quot;colorPrimary&quot;&gt;@color/first&lt;/item&gt;
        &lt;item name=&quot;colorPrimaryDark&quot;&gt;@color/second&lt;/item&gt;
        &lt;item name=&quot;colorAccent&quot;&gt;@color/third&lt;/item&gt;
       ...
        &lt;item name=&quot;colorControlActivated&quot;&gt;@color/first&lt;/item&gt;
        &lt;item name=&quot;colorControlHighlight&quot;&gt;@color/first&lt;/item&gt;
        &lt;item name=&quot;colorControlNormal&quot;&gt;@color/second&lt;/item&gt;
        &lt;item name=&quot;colorSwitchThumbNormal&quot;&gt;@color/second&lt;/item&gt;
        &lt;item name=&quot;colorButtonNormal&quot;&gt;@color/second&lt;/item&gt;
    ...&gt;

How to change the track color of a SwitchCompat

I am defining a color in code as

    [UIColor colorWithHue:32.0/360.0 saturation:0.88 brightness:0.97 alpha:1]

If I try to set the same color in storyboard, when running the App it is a slightly different colour to the one defined in code. If I drag the color to the palate then select a different color and select the palate one again, the HSB values are slightly different. It seems it is snapping to a different (RGB?) color in interface builder.

Color in storyboard not matching UIColor

I have reading [Material Design Guidelines][1] but I don&#39;t know what should be the color of the Ripple if it isn&#39;t black (with alpha).

For example, I have an app with colorPrimary = blue, and colorAccent = red. Actually I am using the colorAccent (with alpha), I should use colorPrimary (with alpha) if I want a color different of black to the ripple?

I checked all app of Google but they never use ripples with color.

An image like I have now:

 ![ripple][2]


  [1]: http://www.google.com/design/spec/material-design/introduction.html
  [2]: http://i.stack.imgur.com/N1roz.png

What should be the color of the Ripple, colorPrimary or colorAccent? (Material Design)

I Set CornerRadius and BorderWidth for UIbutton in User Defined Runtime Attributes. Without adding **layer.borderColor** it works Well and Display border in black color. But when add **layer.borderColor** does not work(does not show border).

![enter image description here][1]


  [1]: http://i.stack.imgur.com/utTId.png


Change UIButton BorderColor in Storyboard

I would like to get the RGB Value of an UIColor in Swift:

    let swiftColor = UIColor(red: 1, green: 165/255, blue: 0, alpha: 1)
    println(&quot;RGB Value is:&quot;);
    println(swiftColor.getRGB()); &lt;&lt;&lt;&lt;&lt;&lt; How to do that ?

In Java I would do it as follows:

    Color cnew = new Color();
    int iColor = cnew.rgb(1, 165/255, 0);
    System.out.println(iColor);

How should I get this value?

How to get the RGB Code (INT) from an UIColor in Swift

How I can make a random color function using Swift?

    import UIKit
    
    class ViewController: UIViewController {
    
        var randomNumber = arc4random_uniform(20)
        var randomColor = arc4random()
        
        //Color Background randomly
        func colorBackground() {
            
            // TODO: set a random color
            view.backgroundColor = UIColor.yellow
        
        }
    }


How to make a random color with Swift

I set a `UIColor` using rgb to a background of a `UILabel`. I&#39;m trying to adjust the `alpha` only. How can I modify the alpha of an existing rgb `UIColor`?

**Edit**

Basically I have `UILabels` that have a set `UIColor` (using rgb), and I won&#39;t know what color the `UILabels` are. At a certain point, I will have to change the `labels` alpha`. How can I just change the labels color alpha?

Adjust alpha of UIColor

Does anyone know what color a `UITextField`&#39;s placeholder text is, by default? I&#39;m trying to set a `UITextView`&#39;s text to the same color. I&#39;ve read elsewhere that it is `UIColor.lightGrayColor()` but it is actually a little lighter.

Content Type	Original Author	Original Content on Stackoverflow
Question	Shakti Chauhan	View Question on Stackoverflow
Solution 1 - Objective C	Onik IV	View Answer on Stackoverflow
Solution 2 - Objective C	George D Girton	View Answer on Stackoverflow
Solution 3 - Objective C	yassine menssi	View Answer on Stackoverflow

Converting UIColor to CGColor in swift

Objective C Problem Overview

Objective C Solutions

Solution 1 - Objective C

Solution 2 - Objective C

Solution 3 - Objective C

How to use generic protocol as a variable type

Why doesn't a child's margin affect a parent's height?

Attributions