In iOS 15, Apple unveiled the UISheetPresentationController class for displaying an expandable backside sheet in iOS apps. On the time, it’s solely accessible within the UIKit framework. For SwiftUI, you both must construct your personal part or depend on third social gathering libraries. Ranging from iOS 16, the SwiftUI framework comes with a brand new modifier referred to as presentationDetents for presenting a resizable backside sheet.
To current a backside sheet, you insert the modifier contained in the sheet view. Right here is an instance:
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struct BasicBottomSheet: View {     @State personal var showSheet = false      var physique: some View {         VStack {             Button(“Present Backside Sheet”) {                 showSheet.toggle()             }             .buttonStyle(.borderedProminent)             .sheet(isPresented: $showSheet) {                 Textual content(“That is the expandable backside sheet.”)                     .presentationDetents([.medium, .large])             }              Spacer()         }     } } |
You specify a set of detents within the presentationDetents modifier. As proven above, the underside sheet helps each medium and enormous measurement. When it first seems, the underside sheet is displayed in medium measurement. You possibly can broaden it to giant measurement by dragging the sheet.
Controlling its Dimension Utilizing Fraction and Peak
Apart from Apart from the preset detents reminiscent of .medium, you may create a customized detent utilizing .peak and .fraction. Right here is one other instance:
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.presentationDetents([.fraction(0.1), .height(200), .medium, .large]) |
Now the underside helps 4 totally different sizes together with:
- round 10% of the display screen peak
- a set peak of 200 factors
- the usual Medium and Giant sizes
Storing the Chosen Detent
Each time you dismiss the underside sheet, the presentation detent is reset to its authentic state. In different phrases, for the under presentation detents:
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.presentationDetents([.height(200), .medium, .large]) |
Each time you open the underside sheet, it begins with the .peak(200) detent. What if you wish to restore the final chosen detent? On this case, you may declare a state variable to maintain observe of the at present chosen detent:
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@State personal var selectedDetent: PresentationDetent = .medium |
For the presentationDetents modifier, you specify the binding of the variable within the choice parameter:
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.presentationDetents([.height(200), .medium, .large], choice: $selectedDetent) |
SwiftUI then shops the at present chosen detent within the state variable. Even for those who dismiss the underside sheet, the following time if you deliver the underside sheet, it restores to the final chosen detent.
Disguise the Drag Indicator
It is best to see a drag bar indicating that the sheet is resizable. If you wish to disguise the drag indicator, connect the presentationDragIndicator modifier and set it to .hidden:
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.presentationDragIndicator(.hidden) |
Be aware: We’re updating our Mastering SwiftUI e-book for iOS 16. If you wish to begin studying SwiftUI, try the e-book right here. You’ll obtain a free replace later this yr.
Founding father of AppCoda. Creator of a number of iOS programming books together with Starting iOS Programming with Swift and Mastering SwiftUI. iOS App Developer and Blogger. Comply with me at Fb, Twitter and Google+.
