#43: Add the DesignKit package to the project.

* Add ElementTextFieldStyle and static style properties.
* Rename button styles, support sizes and simplify colour.

DesignKit/Sources/TextFields/BorderedInputFieldStyle.swift

@@ -28,22 +28,15 @@ public struct BorderedInputFieldStyle: TextFieldStyle {
     
     public var isEditing: Bool
     public var isError: Bool
+    public var returnKey: UIReturnKeyType?
     
     private var borderColor: Color {
-        if isError {
-            return .element.alert
-        } else if isEditing {
-            return .element.accent
-        } else {
-            return .element.quinaryContent
-        }
+        guard !isError else { return .element.alert }
+        return isEditing ? .element.accent : .element.quinaryContent
     }
     
     private var accentColor: Color {
-        if isError {
-            return .element.alert
-        }
-        return .element.accent
+        isError ? .element.alert : .element.accent
     }
     
     private var textColor: Color {
@@ -62,16 +55,22 @@ public struct BorderedInputFieldStyle: TextFieldStyle {
     }
     
     private var placeholderColor: Color {
-        return .element.tertiaryContent
+        .element.tertiaryContent
     }
         
     private var borderWidth: CGFloat {
-        return isEditing || isError ? 2.0 : 1.5
+        isEditing || isError ? 2.0 : 1.5
     }
     
-    public init(isEditing: Bool = false, isError: Bool = false) {
+    /// Creates the text field style configured as required.
+    /// - Parameters:
+    ///   - isEditing: Whether or not the text field is currently being edited.
+    ///   - isError: Whether or not the text field is currently in the error state.
+    ///   - returnKey: The return key to be used. Pass `nil` for iOS 15+ and use `.submitLabel` instead.
+    public init(isEditing: Bool = false, isError: Bool = false, returnKey: UIReturnKeyType? = .done) {
         self.isEditing = isEditing
         self.isError = isError
+        self.returnKey = returnKey
     }
     
     public func _body(configuration: TextField<_Label>) -> some View {
@@ -80,13 +79,16 @@ public struct BorderedInputFieldStyle: TextFieldStyle {
             .font(.element.callout)
             .foregroundColor(textColor)
             .accentColor(accentColor)
-            .frame(height: 48.0)
+            .padding(.vertical, 12.0)
             .padding(.horizontal, 8.0)
             .background(backgroundColor)
             .clipShape(rect)
             .overlay(rect.stroke(borderColor, lineWidth: borderWidth))
             .introspectTextField { textField in
-                textField.returnKeyType = .done
+                if let returnKey = returnKey {
+                    textField.returnKeyType = returnKey
+                }
+                
                 textField.clearButtonMode = .whileEditing
                 textField.attributedPlaceholder = NSAttributedString(string: textField.placeholder ?? "",
                                                                      attributes: [NSAttributedString.Key.foregroundColor: UIColor(placeholderColor)])

DesignKit/Sources/TextFields/ElementTextFieldStyle.swift

@@ -0,0 +1,100 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+import DesignTokens
+
+@available(iOS 15.0, *)
+public extension TextFieldStyle where Self == ElementTextFieldStyle {
+    static func elementInput(labelText: String? = nil,
+                             footerText: String? = nil,
+                             isError: Bool = false) -> ElementTextFieldStyle {
+        ElementTextFieldStyle(labelText: labelText, footerText: footerText, isError: isError)
+    }
+}
+
+@available(iOS 15.0, *)
+public struct ElementTextFieldStyle: TextFieldStyle {
+    @Environment(\.isEnabled) private var isEnabled
+    @Environment(\.colorScheme) private var colorScheme
+    
+    @FocusState private var isFocused: Bool
+    public let labelText: String?
+    public let footerText: String?
+    public let isError: Bool
+    
+    private var labelColor: Color {
+        guard colorScheme == .light else { return .element.tertiaryContent }
+        return isEnabled ? .element.primaryContent : .element.quaternaryContent
+    }
+    
+    private var footerColor: Color {
+        isError ? .element.alert : .element.tertiaryContent
+    }
+    
+    public init(labelText: String? = nil, footerText: String? = nil, isError: Bool = false) {
+        self.labelText = labelText
+        self.footerText = footerText
+        self.isError = isError
+    }
+    
+    public func _body(configuration: TextField<_Label>) -> some View {
+        VStack(alignment: .leading, spacing: 8) {
+            if let labelText = labelText {
+                Text(labelText)
+                    .font(.element.subheadline)
+                    .foregroundColor(labelColor)
+            }
+            
+            configuration
+                .textFieldStyle(BorderedInputFieldStyle(isEditing: isFocused, isError: isError, returnKey: nil))
+                .focused($isFocused)
+            
+            if let footerText = footerText {
+                Text(footerText)
+                    .font(.element.footnote)
+                    .foregroundColor(footerColor)
+            }
+        }
+    }
+}
+
+@available(iOS 15.0, *)
+struct ElementTextFieldStyle_Previews: PreviewProvider {
+    public static var states: some View {
+        VStack(spacing: 12) {
+            TextField("Placeholder", text: .constant(""))
+                .textFieldStyle(.elementInput(labelText: "Label", footerText: "Footer"))
+            TextField("Placeholder", text: .constant("Input text"))
+                .textFieldStyle(.elementInput(labelText: "Title", footerText: "Footer"))
+            TextField("Placeholder", text: .constant("Bad text"))
+                .textFieldStyle(.elementInput(labelText: "Title", footerText: "Footer", isError: true))
+            TextField("Placeholder", text: .constant(""))
+                .textFieldStyle(.elementInput(labelText: "Title", footerText: "Footer"))
+                .disabled(true)
+        }
+        .padding()
+    }
+    
+    public static var previews: some View {
+        Group {
+            states
+                .preferredColorScheme(.light)
+            states
+                .preferredColorScheme(.dark)
+        }
+    }
+}

DesignKit/Sources/TextFields/RoundedCornerShape.swift

@@ -1,28 +0,0 @@
-// 
-// Copyright 2021 New Vector Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-
-import SwiftUI
-
-struct RoundedCornerShape: Shape {
-
-    let radius: CGFloat
-    let corners: UIRectCorner
-
-    func path(in rect: CGRect) -> Path {
-        let path = UIBezierPath(roundedRect: rect, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
-        return Path(path.cgPath)
-    }
-}