If the application is running in the foreground, iOS won’t show a notification banner or alert. That is by design.

If we receive local or remote notifications while we app is running in the foreground, we’re responsible for passing the information to our users in an app-specific way. Where to handle and process such request?

When I launch safari view controller(SFSafariViewController) by way of present(_:animated:completion:) method, I do not get the default modal transition behaviour, instead the transition is that of push (sliding in from the right), as if I called pushViewController:animated:

This post assumes we have understanding about exporting to mp4 video. The use case example of the discussion exports a video and save it locally inside app’s folder: Document, Cache or Temporary. In my case I am doing some very basic composing of video and saving it to my temporary folder. I want to send this video or share it to my contacts through iMessage or MFMessageComposeViewController. Below is a brief idea on how I am exporting to mp4 video that saves in app’s temporary folder.

let exportURL = URL(fileURLWithPath: NSTemporaryDirectory())
          .appendingPathComponent("filename")
          .appendingPathExtension("mp4")
export.outputFileType = .mp4
export.outputURL = exportURL

export.exportAsynchronously {
  DispatchQueue.main.async {
    switch export.status {
    case .completed:
        print("success")
    default:
      print("Something went wrong during export.")
      print(export.error ?? "unknown error")
      break
    }
  }
}

Now, I found 2 easy effective ways to share or attach video to iMessage or MFMessageComposeViewController.

Note: Discussion in this post assumes we are considering single window based scenario.

Sometimes I need to access the main window of my app to add some temporary views to it - making it appear forefront no matter at what depth of user’s navigation-flow I am in.

From old days of single window based app we have been using very convenient property handed to us: keyWindow

guard let window = UIApplication.shared.keyWindow else {return}

It has been long time. Now this has been deprecated from iOS 13 onwards.

We have our windows accessible from windows array:

let window = UIApplication.shared.windows[0]

A free assumption would be that first window in array would be the main window of the app - being the root. We want the root window so that any view being added be directly on top for our given purpose here. It worked good until unexpected happened. First object did not give UIWindow but UITextEffectsWindow. I could not add my view on the top anymore - adding to UITextEffectsWindow didn’t work for curiosity.

I have been using SKShapeNode extensively to draw quick graphics by filling them with CGPaths for quick visual debugging and making prototypes. For example I can create procedural mountains quickly with SKShapeNode. In early times of spritekit SKShapeNode didn’t have way to render images on it. We have fillTexture available now that allows texture to fill the shape.

let shapeNode = SKShapeNode()
shapeNode.fillTexture = SKTexture(imageNamed: “testImage")

But, Our SKShapeNode is displaying nothing.

Why is that?

I stumbled upon a crash in my app. In my app I have a WKWebView that lets user access web. I tried saving image from a website by long pressing - general way we do in our iOS safari - and app crashed. This user experience behaviour of long pressing and saving image is very common.

The crash error is:

Using native image picker system is easy and solves everyday basic needs of most apps.

Here is an example code that lets user pick images from photo library:

pickerController = UIImagePickerController()
pickerController?.delegate = self
pickerController?.mediaTypes = [“public.image”]
pickerController?.sourceType = .photoLibrary

self.present(pickerController!, animated: true, completion: nil)

We need to implement delegate methods that provides us media info from which we can extract image in our case if available. Here is a code

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    if let image = info[.originalImage] as? UIImage{
    }
}

Our picked image resides inside the key .originalImage which is optional so if something went wrong then it will be nil.

Now, UIImagePickerController also supports basic crop. To activate crop we set the allowsEditing property to true. By default it is false.

In Swift 5 we do no longer have access to substring() methods for they are deprecated. We will discuss all alternatives and understand them in details.

• How to access Characters in String?
• Why Int based Subscript is not available in Swift?
• What is difference between Range and NSRange?
• How does String Indices work?
• How to create Range from String Indices?
• How to get substring with Range?
• How to get substring with NSRange?

Warning of attempt to present view controller is common occurrence when making an easily made mistake. I will take Alert controller for an example to discuss.

Lets’s create a scenario to bring UIAlertController warning message and observe side effect to understand our situation more effectively. Then we will understand on how to fix warning attempt to present UIAlertController. I will present a Detail view controller modally from Main controller, and Main controller will be delegate object assigned to the property of Detail view controller. In our presented view controller I have a dismiss code when back button is pressed. Before dismissing the controller I will call the delegate object - Main controller in this case - to present Alert controller from Main controller.

We use an MFMessageComposeViewController object to display the standard message composition interface in order to send text messages in our app. Properties of MFMessageComposeViewController lets us populate pre-defined recipients and body message before presenting the interface.

Simple code to create and present MFMessageComposeViewController is:

            
if([MFMessageComposeViewController canSendText]){
    MFMessageComposeViewController *picker = [[MFMessageComposeViewController alloc] init];
    picker.messageComposeDelegate = self;
    picker.recipients =@[“1234”];
    picker.body = @“pre-defined message”;
    [self presentViewController:picker animated:YES completion:nil];
}
else{
    NSLog(@“Cannot send text”);
}
            
            

            
if MFMessageComposeViewController.canSendText() {
    let picker = MFMessageComposeViewController()
    picker.messageComposeDelegate = self;
    picker.recipients =[“1234”];
    picker.body = “pre-defined message”;
    self.present(picker, animated: true, completion: nil)
}
else{
    print(“Cannot send text”);
}
            
            

Not so distant, I had stumbled upon a very silly mistake that caused an MFMessageComposeViewController to show blank after presenting.