Add flag to disable EpoxySwiftUIHostingController keyboard avoidance (

#170)

* Add flag to disable `EpoxySwiftUIHostingController` keyboard avoidance

* Update Xcode CI versions

* Update Xcode CI versions again

* Use `ignores` instead of `ignore`

* Update CI simulator version

* Run swiftformat

.github/workflows/main.yml

@@ -12,8 +12,8 @@ jobs:
     strategy:
       matrix:
         xcode:
-        - '13.2.1' # Swift 5.5 (lowest)
-        - '14.0.1' # Swift 5.7 (highest)
+        - '14.3.1' # Swift 5.8 (lowest)
+        - '15.4' # Swift 5.10 (highest)
     steps:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/setup
@@ -27,7 +27,7 @@ jobs:
     strategy:
       matrix:
         xcode:
-        - '14.0.1' # Swift 5.7 (highest)
+        - '15.4' # Swift 5.10 (highest)
     steps:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/setup
@@ -41,8 +41,8 @@ jobs:
     strategy:
       matrix:
         xcode:
-        - '13.2.1' # Swift 5.5 (lowest)
-        - '14.0.1' # Swift 5.7 (highest)
+        - '14.3.1' # Swift 5.8 (lowest)
+        - '15.4' # Swift 5.10 (highest)
     steps:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/setup
@@ -56,8 +56,8 @@ jobs:
     strategy:
       matrix:
         xcode:
-        - '13.2.1' # Swift 5.5  (lowest)
-        - '14.0.1' # Swift 5.7 (highest)
+        - '14.3.1' # Swift 5.8 (lowest)
+        - '15.4' # Swift 5.10 (highest)
     steps:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/setup

CHANGELOG.md

@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Made new layout-based SwiftUI cell rendering option the default.
 - Fixed interaction of SwiftUI bars on visionOS
 - Added flag for forcing layout on a hosted SwiftUI view after layout margins change
+- Updated `EpoxySwiftUIHostingController` with a flag to disable its keyboard avoidance behavior
 
 ## [0.10.0](https://github.com/airbnb/epoxy-ios/compare/0.9.0...0.10.0) - 2023-06-29
 

Rakefile

@@ -13,7 +13,7 @@ namespace :build do
 
   desc 'Builds the EpoxyExample app'
   task :example do
-    xcodebuild 'build -scheme EpoxyExample -destination "platform=iOS Simulator,name=iPhone 12"'
+    xcodebuild 'build -scheme EpoxyExample -destination "platform=iOS Simulator,name=iPhone 14"'
   end
 end
 
@@ -23,12 +23,12 @@ namespace :test do
 
   desc 'Runs unit tests'
   task :unit do
-    xcodebuild 'test -scheme EpoxyTests -destination "platform=iOS Simulator,name=iPhone 12"'
+    xcodebuild 'test -scheme EpoxyTests -destination "platform=iOS Simulator,name=iPhone 14"'
   end
 
   desc 'Runs performance tests'
   task :performance do
-    xcodebuild 'test -scheme PerformanceTests -destination "platform=iOS Simulator,name=iPhone 12"'
+    xcodebuild 'test -scheme PerformanceTests -destination "platform=iOS Simulator,name=iPhone 14"'
   end
 end
 

Sources/EpoxyCore/SwiftUI/EpoxySwiftUIHostingController.swift

@@ -19,15 +19,19 @@ open class EpoxySwiftUIHostingController<Content: View>: UIHostingController<Con
 
   /// Creates a `UIHostingController` that optionally ignores the `safeAreaInsets` when laying out
   /// its contained `RootView`.
-  public convenience init(rootView: Content, ignoreSafeArea: Bool) {
+  public convenience init(rootView: Content, ignoresSafeArea: Bool, ignoresKeyboardAvoidance: Bool) {
     self.init(rootView: rootView)
 
     // We unfortunately need to call a private API to disable the safe area. We can also accomplish
     // this by dynamically subclassing this view controller's view at runtime and overriding its
     // `safeAreaInsets` property and returning `.zero`. An implementation of that logic is
     // available in this file in the `2d28b3181cca50b89618b54836f7a9b6e36ea78e` commit if this API
     // no longer functions in future SwiftUI versions.
-    _disableSafeArea = ignoreSafeArea
+    _disableSafeArea = ignoresSafeArea
+
+    if ignoresKeyboardAvoidance {
+      disableKeyboardAvoidance()
+    }
   }
 
   // MARK: Open
@@ -41,5 +45,53 @@ open class EpoxySwiftUIHostingController<Content: View>: UIHostingController<Con
     // below, e.g. to draw highlight states in a `CollectionView`.
     view.backgroundColor = .clear
   }
+
+  // MARK: Private
+
+  /// Creates a dynamic subclass of this hosting controller's view that disables its keyboard
+  /// avoidance behavior.
+  /// Setting `safeAreaRegions` to `.container` also works but cannot be used since it's
+  /// supported on 16.4+ and we need to support older versions.
+  /// See [here](https://steipete.com/posts/disabling-keyboard-avoidance-in-swiftui-uihostingcontroller/) for more info.
+  private func disableKeyboardAvoidance() {
+    guard let viewClass = object_getClass(view) else {
+      EpoxyLogger.shared.assertionFailure("Unable to determine class of \(String(describing: view))")
+      return
+    }
+
+    let viewClassName = class_getName(viewClass)
+    let viewSubclassName = String(cString: viewClassName).appending("_IgnoresKeyboard")
+
+    // If subclass already exists, just set the class of `view` and return.
+    if let subclass = NSClassFromString(viewSubclassName) {
+      object_setClass(view, subclass)
+      return
+    }
+
+    guard let viewSubclassNameUTF8 = (viewSubclassName as NSString).utf8String else {
+      EpoxyLogger.shared.assertionFailure("Unable to get utf8String of \(viewSubclassName)")
+      return
+    }
+    guard let viewSubclass = objc_allocateClassPair(viewClass, viewSubclassNameUTF8, 0) else {
+      EpoxyLogger.shared.assertionFailure(
+        "Unable to subclass \(viewClass) with \(viewSubclassNameUTF8)")
+      return
+    }
+
+    let selector = NSSelectorFromString("keyboardWillShowWithNotification:")
+    guard let method = class_getInstanceMethod(viewClass, selector) else {
+      EpoxyLogger.shared.assertionFailure("Unable to locate method \(selector) on \(viewClass)")
+      objc_disposeClassPair(viewSubclass)
+      return
+    }
+
+    let keyboardWillShowOverride: @convention(block) (AnyObject, AnyObject) -> Void = { _, _ in }
+    let implementation = imp_implementationWithBlock(keyboardWillShowOverride)
+    let typeEncoding = method_getTypeEncoding(method)
+    class_addMethod(viewSubclass, selector, implementation, typeEncoding)
+
+    objc_registerClassPair(viewSubclass)
+    object_setClass(view, viewSubclass)
+  }
 }
 #endif

Sources/EpoxyCore/SwiftUI/EpoxySwiftUIHostingView.swift

@@ -67,7 +67,8 @@ public final class EpoxySwiftUIHostingView<RootView: View>: UIView, EpoxyableVie
     epoxyContent = EpoxyHostingContent(rootView: style.initialContent.rootView)
     viewController = EpoxySwiftUIHostingController(
       rootView: .init(content: epoxyContent, environment: epoxyEnvironment),
-      ignoreSafeArea: true)
+      ignoresSafeArea: true,
+      ignoresKeyboardAvoidance: true)
 
     dataID = style.initialContent.dataID ?? DefaultDataID.noneProvided as AnyHashable
     forceLayoutOnLayoutMarginsChange = style.forceLayoutOnLayoutMarginsChange