How to build container view in SwiftUI

Issue #780 To make a container view that accepts child content, we use ViewBuilder struct ContainerView<Content: View>: View { let content: Content init(@ViewBuilder content: () -> Content) { self.content = content() } var body: some View { content } } From Swift 5.4, it can synthesize the init, so we can declare resultBuilder for stored property struct AwesomeContainerView<Content: View>: View { @ViewBuilder let content: Content var body: some View { content } } ...

February 24, 2021 路 1 min 路 Khoa Pham

How to tune performance with ButtonBehavior in SwiftUI

Issue #779 With Xcode 12.4, macOS 11.0 app. Every time we switch the system dark and light mode, the CPU goes up to 100%. Instruments show that there鈥檚 an increasing number of ButtonBehavior Suspect State in a row in LazyVStack Every cell has its own toggle state struct Cell: View { enum ToggleState { case general case request case response } let item: Item @State private var toggleState: ToggleState = ....

February 24, 2021 路 1 min 路 Khoa Pham

How to use GroupBox in SwiftUI

Issue #778 For now using GroupBox has these issues in macOS Prevents dragging scroll indicator to scroll Switch from light to dark mode may cause 100% CPU usage ...

February 23, 2021 路 1 min 路 Khoa Pham

How to suppress selector warning in Swift

Issue #777 Sometimes we need to use dynamic selector and that triggers warning in Swift Selector("updateWithCount:") // Use '#selector' instead of explicitly constructing a 'Selector' In ObjC we can use clang macro to suppress, like below #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wdeprecated-implementations" - (void) deprecated_objc_method_override { } #pragma clang diagnostic pop But in Swift, we can just use a dummy NSObject that has the needed methods, like...

February 18, 2021 路 1 min 路 Khoa Pham

How to make simple search bar in SwiftUI

Issue #776 We need to use a custom Binding to trigger onChange as onEditingChanged is only called when the user selects the textField, and onCommit is only called when return or done button on keyboard is tapped. import UIKit import SwiftUI import EasySwiftUI struct SearchBar: View { @Binding var searchText: String let onChange: () -> Void @State private var showsCancelButton: Bool = false var body: some View { return HStack { textField cancelButton } } private var searchTextBinding: Binding<String> { Binding<String>(get: { searchText }, set: { newValue in DispatchQueue....

February 17, 2021 路 1 min 路 Khoa Pham

How to fix share and action extension not showing up in iOS 14

Issue #775 My share sheet and action extension not showing up in iOS 14, built-in Xcode 12.3. The solution is to restart test device, and it shows up again. Also make sure your extension targets have the same version and build number, and same deployment target <dict> <key>NSExtensionAttributes</key> <dict> <key>NSExtensionActivationRule</key> <dict> <key>NSExtensionActivationDictionaryVersion</key> <integer>2</integer> <key>NSExtensionActivationSupportsText</key> <true/> <key>NSExtensionActivationSupportsWebURLWithMaxCount</key> <integer>1</integer> <key>NSExtensionActivationSupportsWebPageWithMaxCount</key> <integer>1</integer> </dict> <key>NSExtensionJavaScriptPreprocessingFile</key> <string>MyPreprocessor</string> <key>NSExtensionActivationUsesStrictMatching</key> <integer>2</integer> </dict> ...

February 17, 2021 路 1 min 路 Khoa Pham

How to add home screen quick action in SwiftUI

Issue #774 Start by defining your quick actions. You can use UIApplicationShortcutIcon(type:) for predefined icons, or use UIApplicationShortcutIcon(systemImageName:) for SFSymbol enum QuickAction: String { case readPasteboard case clear var shortcutItem: UIApplicationShortcutItem { switch self { case .readPasteboard: return UIApplicationShortcutItem( type: rawValue, localizedTitle: "Read Pasteboard", localizedSubtitle: "", icon: UIApplicationShortcutIcon(type: .add), userInfo: nil ) case .clear: return UIApplicationShortcutItem( type: rawValue, localizedTitle: "Clear Pasteboard", localizedSubtitle: "", icon: UIApplicationShortcutIcon(systemImageName: SFSymbol.wind.rawValue), userInfo: nil ) } } } Add a service to store selected quick action....

February 10, 2021 路 2 min 路 Khoa Pham

How to use EquatableView in SwiftUI

Issue #773 From John Harper 鈥檚 tweet SwiftUI assumes any Equatable.== is a true equality check, so for POD views it compares each field directly instead (via reflection). For non-POD views it prefers the view鈥檚 == but falls back to its own field compare if no ==. EqView is a way to force the use of ==. When it does the per-field comparison the same rules are applied recursively to each field (to choose direct comparison or == if defined)....

February 8, 2021 路 1 min 路 Khoa Pham

How to add new property in Codable struct in SwiftUI

Issue #772 I use Codable structs in my apps for preferences, and bind them to SwiftUI views. If we add new properties to existing Codable, it can鈥檛 decode with old saved json as we require new properties. We can either do cutom decoding with container, but this can result in lots more code and mistakes if we have many properties inside our struct. The quick workaround is to declare new properties as optional, and use a computed property to wrap that....

February 8, 2021 路 1 min 路 Khoa Pham

How to show close button in NSTextField in AppKit

Issue #771 Use NSSearchField instead...

February 6, 2021 路 1 min 路 Khoa Pham

How to handle escape in NSTextField in SwiftUI

Issue #770 Handle cancelOperation somewhere up in responder chain class MyWindow: NSWindow { let keyHandler = KeyHandler() override func cancelOperation(_ sender: Any?) { super.cancelOperation(sender) keyHandler.onEvent(.esc) } } ...

February 6, 2021 路 1 min 路 Khoa Pham

How to fit ScrollView to content in SwiftUI

Issue #769 If we place ScrollView inside HStack or VStack, it takes all remaining space. To fit ScrollView to its content, we need to get its content size and constrain ScrollView size. Use a GeometryReader as Scrollview content background, and get the local frame import SwiftUI struct HSearchBar: View { @State private var scrollViewContentSize: CGSize = .zero var body: some View { HStack { searchButton ScrollView(.horizontal, showsIndicators: false) { HStack(spacing: 12) { ForEach(store....

February 6, 2021 路 1 min 路 Khoa Pham

How to show modal window in SwiftUI for macOS

Issue #768 Use custom NSWindow, set level in becomeKey and call NSApp.runModal to show modal final class ModalWindow: NSWindow { override func becomeKey() { super.becomeKey() level = .statusBar } override func close() { super.close() NSApp.stopModal() } } let window = ModalWindow( contentRect: .zero, styleMask: [.titled, .closable], backing: .buffered, defer: false ) window.titlebarAppearsTransparent = true window.title = "Manage collections" window.center() window.isReleasedWhenClosed = false self.window = window let view = CollectionSettingsView(store: Store.shared) ....

February 3, 2021 路 1 min 路 Khoa Pham

How to use ViewBuilder in SwiftUI

Issue #767 SwiftUI 鈥檚 ViewBuilder is a custom parameter attribute that constructs views from closures. It is available in body and most SwiftUI modifiers public protocol View { associatedtype Body : View @ViewBuilder var body: Self.Body { get } } public func contextMenu<MenuItems>(@ViewBuilder menuItems: () -> MenuItems) -> some View where MenuItems : View In these ViewBuilder enabled places we can perform conditional logic to construct views. For example here in our SampleView, we have switch statement in body...

February 2, 2021 路 3 min 路 Khoa Pham

How to use custom Key for NSCache

Issue #766 Need to use a class, best is to subclass from NSObject let cache = NSCache<Key, UIImage>() final class Key: NSObject { override func isEqual(_ object: Any?) -> Bool { guard let other = object as? Key else { return false } return url == other.url && size == other.size } override var hash: Int { return url.hashValue ^ Int(size.width) ^ Int(size.height) } let url: URL let size: CGSize init(url: URL, size: CGSize) { self....

January 30, 2021 路 1 min 路 Khoa Pham

How to show multiple popover in SwiftUI

Issue #765 In SwiftUI currently, it鈥檚 not possible to attach multiple .popover to the same View. But we can use condition to show different content struct ClipboardCell: View { enum PopoverStyle { case raw case preview } @Binding var showsPopover: Bool @Binding var popoverStyle: PopoverStyle var body: some View { VStack { header content .popover(isPresented: $showsPopover) { switch popoverStyle { case .raw: ViewRawView(item: item) case .preview: PreviewView(item: item) } } footer } } } ...

January 29, 2021 路 1 min 路 Khoa Pham

How to handle keyDown in SwiftUI for macOS

Issue #764 Use a custom KeyAwareView that uses an NSView that checks for keyDown method. In case we can鈥檛 handle certain keys, call super.keyDown(with: event) import SwiftUI import KeyboardShortcuts struct KeyAwareView: NSViewRepresentable { let onEvent: (Event) -> Void func makeNSView(context: Context) -> NSView { let view = KeyView() view.onEvent = onEvent DispatchQueue.main.async { view.window?.makeFirstResponder(view) } return view } func updateNSView(_ nsView: NSView, context: Context) {} } extension KeyAwareView { enum Event { case upArrow case downArrow case leftArrow case rightArrow case space case delete case cmdC } } private class KeyView: NSView { var onEvent: (KeyAwareView....

January 29, 2021 路 1 min 路 Khoa Pham

How to extend custom View in SwiftUI

Issue #763 I usually break down a big struct into smaller views and extensions. For example I have a ClipboardCell that has a lot of onReceive so I want to move these to another component. One way to do that is to extend ClipboardCell struct ClipboardCell: View { let isSelected: Bool @State var showsPreview: Bool @State var showsViewRaw: Bool let onCopy: () -> Void let onDelete: () -> Void } extension ClipboardCell { func onReceiveKeyboard() -> some View { self....

January 28, 2021 路 3 min 路 Khoa Pham

How to use Sparkle for macOS app

Issue #762 Install Sparkle For now, the latest stable version is 1.24.0 which supports CocoaPods OK, but still, have issues with SPM. Support non sandboxed apps Version 2.0.0 is in beta and supports sandboxed apps To install, use CocoaPods platform :osx, '11.0' target 'MyApp' do # Comment the next line if you don't want to use dynamic frameworks use_frameworks! pod 'Sparkle' end Sign In your target, choose Signing & Capability tab, change Signing Certificate from Locally to Development for code sign to work for embedded frameworks...

January 26, 2021 路 2 min 路 Khoa Pham

How to use ScrollViewReader in SwiftUI

Issue #761 Explicitly specify id ScrollView { ScrollViewReader { proxy in LazyVStack(spacing: 10) { ForEach(items) { item in Cell(item: item) .id(item.id) } } .padding() .onReceiveKeyboard(onNext: { onNext() if let item = selectedItem { proxy.scrollTo(item.id, anchor: .center) } }, onPrevious: { onPrevious() if let item = selectedItem { proxy.scrollTo(item.id, anchor: .center) } }) } } I usually extract ScrollViewReader into a helper function that use onChange to react to state changes...

January 21, 2021 路 1 min 路 Khoa Pham