MultiModal

Introduction

By default, SwiftUI views with multiple modal modifiers (e.g. .sheet, .alert) in the same body will only use the last one in the chain of modifiers and ignore all previous ones.

struct NoMultiModalDemoView: View {
    @State var sheetAPresented = false
    @State var sheetBPresented = false
    @State var sheetCPresented = false

    var body: some View {
        VStack(spacing: 20) {
            Button("Sheet A") { sheetAPresented = true }
            Button("Sheet B") { sheetBPresented = true }
            Button("Sheet C") { sheetCPresented = true }
        }
        .sheet(isPresented: $sheetAPresented) { Text("Sheet A") } // does not work
        .sheet(isPresented: $sheetBPresented) { Text("Sheet B") } // does not work
        .sheet(isPresented: $sheetCPresented) { Text("Sheet C") } // works
    }
}

MultiModal brings a .multiModal modifier to declare multiple modal modifiers in the same view body.

struct MultiModalDemoView: View {
    @State var sheetAPresented = false
    @State var sheetBPresented = false
    @State var sheetCPresented = false

    var body: some View {
        VStack(spacing: 20) {
            Button("Sheet A") { sheetAPresented = true }
            Button("Sheet B") { sheetBPresented = true }
            Button("Sheet C") { sheetCPresented = true }
        }
        .multiModal {
            $0.sheet(isPresented: $sheetAPresented) { Text("Sheet A") } // works
            $0.sheet(isPresented: $sheetBPresented) { Text("Sheet B") } // works
            $0.sheet(isPresented: $sheetCPresented) { Text("Sheet C") } // works
        }
    }
}

Disclaimer

MultiModal does not enable “nested” modals; it just enables multiple modals appearing within a view body one at a time. For this reason, it’s recommended that your modal presentation be dependant on a source of truth that ensures only one of them is presented at any given time.

Hopefully Apple will introduce support for multiple modals in a future iteration of SwiftUI, rendering this library unnecessary.

Benchmarks

MacBook Pro (14-inch, 2021)
Apple M1 Pro (10 cores, 8 performance and 2 efficiency)
32 GB Memory

$ swift run -c release Benchmarks

name     time        std        iterations
------------------------------------------
Modifier 2416.000 ns ±  15.72 %     571301