The basic basis of Swift dialogs

The basic basis of Swift dialogs

Suppose a non-engineer friend who is studying Swift recently asks, "What is a dialog? How do you build it?" I will summarize the basics of the dialog.

What is a dialog?

Abbreviation for a small window "dialog box" that appears to prompt the user for input or to notify them of something.

For example, after pressing the logout button when logging out, "Are you sure you want to log out?" (Choice: "Yes" or "No") is displayed at the top of the display screen.

Implementation code

First, I will write the basic code.

//This time, create it as a displayDialog method.
func displayDialog(){
  //The main subject is from here
  //Set an instance of the dialog.
  //Set title and message as String type
  //preferredStyle explained later
  let mDialog = UIAllertControlle(title: "title", message: "Message content", preferredStyle: .alert)
  //Create a choice (button) * Only one this time
  //Select title and style * Style will be described later
  mDialog.addAction(UIAlertAction(title: "Button title", style: .default, handler: { action in
            //Enter the operation when tapping here

  //Show dialog
  self.present(mDialog,animated: true,completion: nil)


STEP1 Set the dialog instance + enter various values

First, create an instance of the dialog "AlertController". "Title" "message" "preferredStyle" is required as an argument.

title Enter the title of the dialog in String type

message Enter the body to be displayed in the dialog as a String type

preferredStyle .alert: Display in the center of the screen .actionSheet: Display at the bottom of the screen in a format that rises from the bottom.

STEP2 Set dialog buttons

Use in .addAction to set options (buttons) in the dialog. Set the action when selected by UIAlertAction. "Title", "style" and "handler" are required as arguments.

title Enter the button title in String type

style Default: Normal choice Destructive: Displayed in red (* Used when displaying negative choices) Cancel: Displayed at the bottom and only one can be displayed

handler Enter the action when tapping

STEP3 Display dialog

Display using present


For dialogs, there is a library called SCLAlertView that allows you to easily display cool animated dialogs. You may try using that.

[Swift] About SCLAlertView, which can easily display cool animation alerts


Putting it all together like this, I found that the dialog is very simple, but there are options such as each option, and you can make various adjustments according to the purpose. There is a big merit in learning systematic knowledge even in the basic part by stopping the output once.

Normally, I use Default without thinking about it, so I feel the need to know the options that can be specified like this time.

I would like to make detailed settings in the future according to the intended use.

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