It&#39;s a convenience macro to save you typing **nonnull** in your headers.  From the *Swift* blog detailing how new safety features have been incorporated back in *Objective-C*:

&gt; To ease adoption of the new annotations, you can mark certain regions
&gt; of your Objective-C header files as audited for nullability. Within
&gt; these regions, any simple pointer type will be assumed to be nonnull.

See Nullability and Objective-C - https://developer.apple.com/swift/blog/?id=25 

I accidentally typed in a git commit --amend. This is a mistake because I realized that the commit is actually entirely new and it should be committed with a new message. I want to make a new commit. How do I undo this?

How to undo a git commit --amend

I want to create a string with embedded information.  One way (not the only way) of achieving what I want is called [string interpolation][1] or variable substitution, wherein placeholders in a string are replaced with actual values.

In C, I would do something like this:

&lt;!-- language: lang-c --&gt;

    printf(&quot;error! value was %d but I expected %d&quot;,actualValue,expectedValue)

whereas if I were programming in python, I would do something like this:

&lt;!-- language: lang-python --&gt;

    &quot;error! value was {0} but I expected {1}&quot;.format(actualValue,expectedValue)

both of these are examples of string interpolation.

How can I do this in C++?

**Important Caveats**:

1. I know that I can use ``std::cout`` if I want to print such a message to standard output (not string interpolation, but prints out the kind of string I want):

&lt;!-- language: lang-c++ --&gt;

    cout &lt;&lt; &quot;error! value was &quot; &lt;&lt; actualValue &lt;&lt; &quot; but I expected &quot;
    &lt;&lt; expectedValue;

I don&#39;t want to *print* a string to stdout.  I want to pass a `std::string` as an argument to a function (e.g. the constructor of an exception object).

2. I am using C++11, but portability is potentially an issue, so knowing which methods work and don&#39;t work in which versions of C++ would be a plus.

**Edit**

3. For my immediate usage, I&#39;m not concerned about performance (I&#39;m raising an exception for cryin&#39; out loud!).  *However*, knowing the relative performance of the various methods would be very very useful in general.

4. Why not just use printf itself (C++ is a superset of C after all...)?  [This answer][2] discusses some reasons why not.  As far as I can understand, type safety is a big reason: if you put %d, the variable you put in there had better really be convertible to an integer, as that&#39;s how the function figures out what type it is.  It would be much safer to have a method which uses compile-time knowledge of the actual type of the variables to be inserted.


  [1]: https://en.wikipedia.org/wiki/String_interpolation
  [2]: https://stackoverflow.com/a/2872576/407588

How to construct a std::string with embedded values, i.e. &quot;string interpolation&quot;?

I am following an online tutorial from team tree house and one of the steps is to create an NSManagedObject subclass for my data model. 

When I did that the code automatically generated a class and set of macros at the beginning and and the end:

**NS_ASSUME_NONNULL_BEGIN**

**NS_ASSUME_NONNULL_END**

I was searching online but I could not find any documentation about what these guys are doing here. By the way they were defined in the header **NSObjCRuntime.h**

Any ideas what purpose they serve?


NS_ASSUME_NONNULL_BEGIN Macro

I am following an online tutorial from team tree house and one of the steps is to create an NSManagedObject subclass for my data model.
When I did that the code automatically generated a class and set of macros at the beginning and and the end:
NS_ASSUME_NONNULL_BEGIN
NS_ASSUME_NONNULL_END
I was searching online but I could not find any documentation about what these guys are doing here. By the way they were defined in the header NSObjCRuntime.h
Any ideas what purpose they serve?

I&#39;m trying to get my app working in **Xcode 8.0**, and am running into an error. I know this code worked fine in previous versions of swift, but I&#39;m assuming the code for this is changed in the new version. Here&#39;s the code I&#39;m trying to run:

    let settings = UIUserNotificationSettings(forTypes: [.Sound, .Alert, .Badge], categories: nil)     
    UIApplication.sharedApplication().registerUserNotificationSettings(settings)
    UIApplication.shared().registerForRemoteNotifications()

The error that I&#39;m getting is &quot;Argument labels &#39;(forTypes:, categories:)&#39; do not match any available overloads&quot;

Is there a different command that I could try to get this working?

Registering for Push Notifications in Xcode 8/Swift 3.0?

Can anyone tell me how I can mimic the bottom sheet in the new Apple Maps app in iOS 10? 

In Android, you can use a `BottomSheet` which mimics this behaviour, but I could not find anything like that for iOS. 

Is that a simple scroll view with a content inset, so that the search bar is at the bottom? 

I am fairly new to iOS programming so if someone could help me creating this layout, that would be highly appreciated.

This is what I mean by &quot;bottom sheet&quot;:

[![screenshot of the collapsed bottom sheet in Maps][1m]][1] [![screenshot of the expanded bottom sheet in Maps][2m]][2]


  [1]: http://i.stack.imgur.com/doVzS.jpg
  [1m]: http://i.stack.imgur.com/doVzSm.jpg
  [2]: http://i.stack.imgur.com/l9Bgz.jpg
  [2m]: http://i.stack.imgur.com/l9Bgzm.jpg

How can I mimic the bottom sheet from the Maps app?

I converted an NSIndexSet to an [Int] array using the answer at https://stackoverflow.com/a/28964059/6481734 I need to do essentially the opposite, turning the same kind of array back into an NSIndexSet.

Create NSIndexSet from integer array in Swift

I have this in Playground using Swift 3, Xcode 8.0:

    import Foundation
    class Person: NSObject, NSCoding {
        var name: String
        var age: Int
        init(name: String, age: Int) {
            self.name = name
            self.age = age
        }
        required convenience init(coder aDecoder: NSCoder) {
            let name = aDecoder.decodeObject(forKey: &quot;name&quot;) as! String
            let age = aDecoder.decodeObject(forKey: &quot;age&quot;) as! Int
            self.init(
                name: name,
                age: age
            )
        }
        func encode(with aCoder: NSCoder) {
            aCoder.encode(name, forKey: &quot;name&quot;)
            aCoder.encode(age, forKey: &quot;age&quot;)
        }
    }

***
    
create array of Person

    let newPerson = Person(name: &quot;Joe&quot;, age: 10)
    var people = [Person]()
    people.append(newPerson)

***    
encode the array

    let encodedData = NSKeyedArchiver.archivedData(withRootObject: people)
    print(&quot;encodedData: \(encodedData))&quot;)

***    
save to userDefaults

    let userDefaults: UserDefaults = UserDefaults.standard()
    userDefaults.set(encodedData, forKey: &quot;people&quot;)
    userDefaults.synchronize()

***    
check

    print(&quot;saved object: \(userDefaults.object(forKey: &quot;people&quot;))&quot;)
    
***
retreive from userDefaults

    if let data = userDefaults.object(forKey: &quot;people&quot;) {
        let myPeopleList = NSKeyedUnarchiver.unarchiveObject(with: data as! Data)
        print(&quot;myPeopleList: \(myPeopleList)&quot;)
    }else{
        print(&quot;There is an issue&quot;)
    }

***    
just check the archived data

    if let myPeopleList = NSKeyedUnarchiver.unarchiveObject(with: encodedData){
       print(&quot;myPeopleList: \(myPeopleList)&quot;)
    }else{
       print(&quot;There is an issue&quot;)
    }

I&#39;m not able to correctly save the data object to userDefaults, and in addition, the check at the bottom creates the error:

  &gt; Fatal error: Unexpectedly found nil while unwrapping an Optional value

The &quot;check&quot; line also shows the saved object is nil. Is this an error in my object&#39;s NSCoder?

Swift saving and retrieving custom object from UserDefaults

I&#39;m currently developing an iOS application for a client. The submission review process to the store can often be a lengthy process and is relatively new to me. 

My client wants to do a beta test using **TestFlight** as well as submitting the app to the app store afterwards, through **XCode** and **Itunes Connect**.


Scouring Apple&#39;s documentation I can&#39;t seem to get a good idea of following:


- **If I want to update an existing application on the store do I have to go through the review process again in full?**&lt;br&gt;&lt;br&gt;

- **If I have my app approved for beta testing release through TestFlight, is this taken into consideration when submitting the app for review to the store?**&lt;br&gt;&lt;br&gt;

- **If I want to test a new build through TestFlight, do I need to go through the beta review process again in full?**&lt;br&gt;&lt;br&gt;

- **If an app is approved on the app store, does it automatically pass the beta review?**&lt;br&gt; 
(This sounds counterintuitive considering you don&#39;t want to do a beta test after releasing to the store but in a scenario where you may want to do a closed release of an update for testing while a live version is up on the store)


iOS app submission and beta review process

I am using XCode 8 and testing with iOS 10.2 Beta.

I have added the Photos, PhotosUI and MobileCoreServices frameworks to project. 

Very simple code:

    #import &lt;Photos/Photos.h&gt;
    #import &lt;PhotosUI/PhotosUI.h&gt;
    #import &lt;MobileCoreServices/MobileCoreServices.h&gt;
    
    @interface ViewController : UIViewController &lt;UIImagePickerControllerDelegate, UINavigationControllerDelegate, PHLivePhotoViewDelegate&gt;
    
    @property (strong, nonatomic) IBOutlet UIImageView *imageview;
    
    @end

and implementation:


    - (IBAction)grab:(UIButton *)sender{
        UIImagePickerController *picker = [[UIImagePickerController alloc]init];
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        picker.allowsEditing = NO;
        picker.delegate = self;
        
        // make sure we include Live Photos (otherwise we&#39;ll only get UIImages)
        NSArray *mediaTypes = @[(NSString *)kUTTypeImage, (NSString *)kUTTypeLivePhoto];
        picker.mediaTypes = mediaTypes;
        
        // bring up the picker
        [self presentViewController:picker animated:YES completion:nil];
    }

As soon as I tap the button, the app crashes with very useless error:

`[access] &lt;private&gt;`

That&#39;s it. Nothing else.

Using break statements, the app seems to crash at &quot;presentViewController&quot;.

This is a brand new app and I don&#39;t have anything else in the UI other than the grab button.

Also, testing on iOS 9.3, this works fine. Am I missing something which might be changed in iOS 10?


iOS 10 error [access] &lt;private&gt; when using UIImagePickerController

I was trying to convert syntax of old Swift project to new one as per few suggestion on Stack Overflow I tried converting it through **Edit &gt; Convert &gt; To latest Syntax** that did not work properly instead I started getting new errors shown as below 
 &gt; Command/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc
failed with exit code 1

And 
&gt; Command /usr/bin/ditto failed with exit code 1

[![enter image description here][1]][1]

I tried https://stackoverflow.com/questions/26156561/xcode-6-0-1-command-applications-xcode-app-contents-developer-toolchains-xcoded, but it&#39;s a different situation.

  [1]: https://i.stack.imgur.com/1x7SP.png


ERROR &quot;swiftc failed with exit code 1&quot; when converting to latest syntax

In iOS 9.3, the `didReceiveRemoteNotification` method gets called on both of the following occasions. 

1) When the push notification is received 
2) When the user launches the app by tapping on the notification.

But on iOS 10, I notice that the `didReceiveRemoteNotification` method does **NOT** fire when the user launches the app by tapping on the notification. It&#39;s called only when the notification is received. Hence, I cannot do any further action after the app is launched from notification.

What should be the fix for this? Any idea?

didReceiveRemoteNotification not called, iOS 10

    2016-09-17 15:16:04.386085 appDemo[2371:94976] [] __nwlog_err_simulate_crash simulate crash already simulated **&quot;nw_socket_set_common_sockopts setsockopt SO_NOAPNFALLBK failed: [42] Protocol not available&quot;**
    2016-09-17 15:16:04.386676 appDemo[2371:94976] [] nw_socket_set_common_sockopts setsockopt SO_NOAPNFALLBK failed: [42] Protocol not available, dumping backtrace:
            [x86_64] libnetcore-856.1.8
        0   libsystem_network.dylib             0x0000000112dc780e __nw_create_backtrace_string + 123
        1   libnetwork.dylib                    0x0000000113bfa194 nw_socket_add_input_handler + 3002
        2   libnetwork.dylib                    0x0000000113bd7db8 nw_endpoint_flow_attach_protocols + 3768
        3   libnetwork.dylib                    0x0000000113bd6dd5 nw_endpoint_flow_setup_socket + 563
        4   libnetwork.dylib                    0x0000000113bd5b34 -[NWConcrete_nw_endpoint_flow startWithHandler:] + 2612
        5   libnetwork.dylib                    0x0000000113bf0d11 nw_endpoint_handler_path_change + 1261
        6   libnetwork.dylib                    0x0000000113bf0740 nw_endpoint_handler_start + 570
        7   libdispatch.dylib                   0x0000000112b44980 _dispatch_call_block_and_release + 12
        8   libdispatch.dylib                   0x0000000112b6e
    2016-09-17 15:16:04.387153 appDemo[2371:94976] [] nw_endpoint_flow_attach_protocols [2 192.168.0.100:80 in_progress socket-flow (satisfied)] Attached flow protocol
    2016-09-17 15:16:04.387679 appDemo[2371:94976] [] nw_connection_endpoint_report [2 192.168.0.100:80 in_progress socket-flow (satisfied)] reported event flow:start_connect

I&#39;m using `xcode 8` version with `ios 10`. Now, I&#39;m working an API. If, I use the API in `Xcode 7` its works fine but when same API I used in `xcode 8` error message appears Unable to parse.


Error: Protocol not available, dumping backtrace

Apple with iOS 10 has deprecated `openURL: for openURL:option:completionHandler`
If I have:

     [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@&quot;https://www.google.com&quot;]];

How it will become? `options:&lt;#(nonnull NSDictionary&lt;NSString *,id&gt; *)#&gt;` in detail

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@&quot;https://www.google.com&quot;] options:&lt;#(nonnull NSDictionary&lt;NSString *,id&gt; *)#&gt; completionHandler:nil];

Thanks


Update
`options:@{}` For empty dictionary with no key and value
http://useyourloaf.com/blog/querying-url-schemes-with-canopenurl/

openURL: deprecated in iOS 10

The projects page seems to be disappeared from Xcode 8. I used this page for deleting the derived data.

Any idea how can I delete derived data from within Xcode 8?

How can I delete derived data in Xcode 8?

In earlier versions of Swift, one could create a delay with the following code:

    let time = dispatch_time(dispatch_time_t(DISPATCH_TIME_NOW), 4 * Int64(NSEC_PER_SEC))
    dispatch_after(time, dispatch_get_main_queue()) {
        //put your code which should be executed with a delay here
    }

But now, in Swift 3, Xcode automatically changes 6 different things but then the following error appears: &quot;Cannot convert `DispatchTime.now` to expected value `dispatch_time_t` aka `UInt64`.&quot;

How can one create a delay before running a sequence of code in Swift 3?

How to program a delay in Swift 3

Among the new features announced in [Xcode 8][1], we can see 

&quot;Auto-generate Quick Help documentation&quot; : 

[![enter image description here][2]][2]

Is this the end of manual code documentation like we [can learn on this article from NSHipster][3] ?

Can someone outline the pros and cons of this new feature ? [Does it replace tools like Jazzy][4] ?

I couldn&#39;t find more information about the new feature.

  [1]: https://developer.apple.com/xcode/
  [2]: http://i.stack.imgur.com/SEVhe.png
  [3]: http://nshipster.com/swift-documentation/
  [4]: https://github.com/realm/jazzy

Content Type	Original Author	Original Content on Stackoverflow
Question	user5412293	View Question on Stackoverflow
Solution 1 - Ios	DDP	View Answer on Stackoverflow

NS_ASSUME_NONNULL_BEGIN Macro

Ios Problem Overview

Ios Solutions

Solution 1 - Ios

How to construct a std::string with embedded values, i.e. "string interpolation"?

How to undo a git commit --amend

Attributions