day_62.md

Day 62

Saurabh Jamadagni
17th October, 2022

• Start of project Instafilter! Two key takeaways are going to be how to use Apple's Core Image framework and how to integrate SwiftUI with UIKit.

Property wrappers and their struct conundrum

• Basically, each property wrapper has a struct behing it.
• Press cmd + shift + O > State.
• Each wrapper wraps around a certain value and it gets a { get nonumutating set }.
• This implies when you change the value of a binding, it is calling a nonmutating set. Thus the didset on a @State property will never be triggered.
• Whereas if you assign a completely new value, which results in the destruction of the previous struct and sets a new struct for the lack of a better description, the didset will be triggered.
• So how do you figure out when a binding value changes internally?

The onChange modifier

• The onChange modifier can be used to figure if a property changes through the nonmutating set property.

.onChange(of: blurAmount) { newValue in
    print("New value is \(newValue)")
}

Multiple options with confirmationDialog

• Are different from alerts but are shown in a similar fashion. Bind to a boolean which triggers the confirmation.
• use confirmationDialog instead of alert and the rest is very very similar.

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