Pointer interceptor implementations (#5594)

This is essentially the same PR as #5500, with pubspec updates
Addresses flutter/flutter#30143 by adding an iOS implementation

This PR is Part 2 of #5233

Author: LouiseHsu

packages/pointer_interceptor/pointer_interceptor/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Adds iOS implementation.
+
 ## 0.9.3+7
 
 * Updates metadata to point to new source folder

packages/pointer_interceptor/pointer_interceptor/README.md

@@ -1,24 +1,25 @@
 # pointer_interceptor
 
-`PointerInterceptor` is a widget that prevents mouse events (in web) from being captured by an underlying [`HtmlElementView`](https://api.flutter.dev/flutter/widgets/HtmlElementView-class.html).
+|             | iOS     | Web |
+|-------------|---------|-----|
+| **Support** | iOS 11+ | Any |
 
-You can use this widget in a cross-platform app freely. In mobile, where the issue that this plugin fixes does not exist, the widget acts as a pass-through of its `children`, without adding anything to the render tree.
+`PointerInterceptor` is a widget that prevents mouse events from being captured by an underlying [`HtmlElementView`](https://api.flutter.dev/flutter/widgets/HtmlElementView-class.html) in web, or an underlying [`PlatformView`](https://api.flutter.dev/flutter/widgets/PlatformViewLink-class.html) on iOS.
 
 ## What is the problem?
 
-When overlaying Flutter widgets on top of `HtmlElementView` widgets that respond to mouse gestures (handle clicks, for example), the clicks will be consumed by the `HtmlElementView`, and not relayed to Flutter.
+When overlaying Flutter widgets on top of `HtmlElementView`/`PlatformView` widgets that respond to mouse gestures (handle clicks, for example), the clicks will be consumed by the `HtmlElementView`/`PlatformView`, and not relayed to Flutter.
 
-The result is that Flutter widget's `onTap` (and other) handlers won't fire as expected, but they'll affect the underlying webview.
+The result is that Flutter widget's `onTap` (and other) handlers won't fire as expected, but they'll affect the underlying native platform view.
 
 |The problem...|
 |:-:|
 |![Depiction of problematic areas](https://raw.githubusercontent.com/flutter/packages/main/packages/pointer_interceptor/doc/img/affected-areas.png)|
 |_In the dashed areas, mouse events won't work as expected. The `HtmlElementView` will consume them before Flutter sees them._|
 
-
 ## How does this work?
 
-`PointerInterceptor` creates a platform view consisting of an empty HTML element. The element has the size of its `child` widget, and is inserted in the layer tree _behind_ its child in paint order.
+In web, `PointerInterceptor` creates a platform view consisting of an empty HTML element, while on iOS it creates an empty `UIView` instead. The element has the size of its `child` widget, and is inserted in the layer tree _behind_ its child in paint order.
 
 This empty platform view doesn't do anything with mouse events, other than preventing them from reaching other platform views underneath it.
 

packages/pointer_interceptor/pointer_interceptor/example/.gitignore

@@ -32,7 +32,6 @@
 /build/
 
 # Web related
-lib/generated_plugin_registrant.dart
 
 # Symbolication related
 app.*.symbols

packages/pointer_interceptor/pointer_interceptor/example/.metadata

@@ -4,7 +4,27 @@
 # This file should be version controlled and should not be manually edited.
 
 version:
-  revision: e6bd95bc5caa5e34c5b0285a559673984374b7ea
-  channel: master
+  revision: "969911d1d09d6c4f145e9ce27c08093e8c285561"
+  channel: "main"
 
 project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: 969911d1d09d6c4f145e9ce27c08093e8c285561
+      base_revision: 969911d1d09d6c4f145e9ce27c08093e8c285561
+    - platform: ios
+      create_revision: 969911d1d09d6c4f145e9ce27c08093e8c285561
+      base_revision: 969911d1d09d6c4f145e9ce27c08093e8c285561
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

packages/pointer_interceptor/pointer_interceptor/example/integration_test/widget_test.dart

@@ -4,176 +4,13 @@
 
 // ignore_for_file: avoid_print
 
-import 'dart:html' as html;
-
-// Imports the Flutter Driver API.
-import 'package:flutter/src/widgets/framework.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
 
-import 'package:pointer_interceptor_example/main.dart' as app;
-
-final Finder nonClickableButtonFinder =
-    find.byKey(const Key('transparent-button'));
-final Finder clickableWrappedButtonFinder =
-    find.byKey(const Key('wrapped-transparent-button'));
-final Finder clickableButtonFinder = find.byKey(const Key('clickable-button'));
-final Finder backgroundFinder =
-    find.byKey(const ValueKey<String>('background-widget'));
-
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
-
-  group('Without semantics', () {
-    testWidgets(
-        'on wrapped elements, the browser does not hit the background-html-view',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      final html.Element element =
-          _getHtmlElementAtCenter(clickableButtonFinder, tester);
-
-      expect(element.id, isNot('background-html-view'));
-    }, semanticsEnabled: false);
-
-    testWidgets(
-        'on wrapped elements with intercepting set to false, the browser hits the background-html-view',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      final html.Element element =
-          _getHtmlElementAtCenter(clickableWrappedButtonFinder, tester);
-
-      expect(element.id, 'background-html-view');
-    }, semanticsEnabled: false);
-
-    testWidgets(
-        'on unwrapped elements, the browser hits the background-html-view',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      final html.Element element =
-          _getHtmlElementAtCenter(nonClickableButtonFinder, tester);
-
-      expect(element.id, 'background-html-view');
-    }, semanticsEnabled: false);
-
-    testWidgets('on background directly', (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      final html.Element element =
-          _getHtmlElementAt(tester.getTopLeft(backgroundFinder));
-
-      expect(element.id, 'background-html-view');
-    }, semanticsEnabled: false);
-  });
-
-  group('With semantics', () {
-    testWidgets('finds semantics of wrapped widgets',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      if (!_newSemanticsAvailable()) {
-        print('Skipping test: Needs flutter > 2.10');
-        return;
-      }
-
-      final html.Element element =
-          _getHtmlElementAtCenter(clickableButtonFinder, tester);
-
-      expect(element.tagName.toLowerCase(), 'flt-semantics');
-      expect(element.getAttribute('aria-label'), 'Works As Expected');
-    });
-
-    testWidgets(
-        'finds semantics of wrapped widgets with intercepting set to false',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      if (!_newSemanticsAvailable()) {
-        print('Skipping test: Needs flutter > 2.10');
-        return;
-      }
-
-      final html.Element element =
-          _getHtmlElementAtCenter(clickableWrappedButtonFinder, tester);
-
-      expect(element.tagName.toLowerCase(), 'flt-semantics');
-      expect(element.getAttribute('aria-label'),
-          'Never calls onPressed transparent');
-    });
-
-    testWidgets('finds semantics of unwrapped elements',
-        (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      if (!_newSemanticsAvailable()) {
-        print('Skipping test: Needs flutter > 2.10');
-        return;
-      }
-
-      final html.Element element =
-          _getHtmlElementAtCenter(nonClickableButtonFinder, tester);
-
-      expect(element.tagName.toLowerCase(), 'flt-semantics');
-      expect(element.getAttribute('aria-label'), 'Never calls onPressed');
-    });
-
-    // Notice that, when hit-testing the background platform view, instead of
-    // finding a semantics node, the platform view itself is found. This is
-    // because the platform view does not add interactive semantics nodes into
-    // the framework's semantics tree. Instead, its semantics is determined by
-    // the HTML content of the platform view itself. Flutter's semantics tree
-    // simply allows the hit test to land on the platform view by making itself
-    // hit test transparent.
-    testWidgets('on background directly', (WidgetTester tester) async {
-      app.main();
-      await tester.pumpAndSettle();
-
-      final html.Element element =
-          _getHtmlElementAt(tester.getTopLeft(backgroundFinder));
-
-      expect(element.id, 'background-html-view');
-    });
-  });
-}
-
-// Calls [_getHtmlElementAt] passing it the center of the widget identified by
-// the `finder`.
-html.Element _getHtmlElementAtCenter(Finder finder, WidgetTester tester) {
-  final Offset point = tester.getCenter(finder);
-  return _getHtmlElementAt(point);
-}
-
-// Locates the DOM element at the given `point` using `elementFromPoint`.
-//
-// `elementFromPoint` is an approximate proxy for a hit test, although it's
-// sensitive to the presence of shadow roots and browser quirks (not all
-// browsers agree on what it should return in all situations). Since this test
-// runs only in Chromium, it relies on Chromium's behavior.
-html.Element _getHtmlElementAt(Offset point) {
-  // Probe at the shadow so the browser reports semantics nodes in addition to
-  // platform view elements. If probed from `html.document` the browser hides
-  // the contents of <flt-glass-name> as an implementation detail.
-  final html.ShadowRoot glassPaneShadow =
-      html.document.querySelector('flt-glass-pane')!.shadowRoot!;
-  return glassPaneShadow.elementFromPoint(point.dx.toInt(), point.dy.toInt())!;
-}
-
-// TODO(dit): Remove this after flutter master (2.13) lands into stable.
-// This detects that we can do new semantics assertions by looking at the 'id'
-// attribute on flt-semantics elements (it is now set in 2.13 and up).
-bool _newSemanticsAvailable() {
-  final html.ShadowRoot glassPaneShadow =
-      html.document.querySelector('flt-glass-pane')!.shadowRoot!;
-  final List<html.Element> elements =
-      glassPaneShadow.querySelectorAll('flt-semantics[id]');
-  return elements.isNotEmpty;
+  // TODO(louisehsu): given the difficulty of making the same integration tests
+  // work for both web and ios implementations, please find tests in their respective
+  // platform implementation packages.
+  testWidgets('placeholder test', (WidgetTester tester) async {});
 }

packages/pointer_interceptor/pointer_interceptor/example/ios/.gitignore

@@ -0,0 +1,34 @@
+**/dgph
+*.mode1v3
+*.mode2v3
+*.moved-aside
+*.pbxuser
+*.perspectivev3
+**/*sync/
+.sconsign.dblite
+.tags*
+**/.vagrant/
+**/DerivedData/
+Icon?
+**/Pods/
+**/.symlinks/
+profile
+xcuserdata
+**/.generated/
+Flutter/App.framework
+Flutter/Flutter.framework
+Flutter/Flutter.podspec
+Flutter/Generated.xcconfig
+Flutter/ephemeral/
+Flutter/app.flx
+Flutter/app.zip
+Flutter/flutter_assets/
+Flutter/flutter_export_environment.sh
+ServiceDefinitions.json
+Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!default.mode1v3
+!default.mode2v3
+!default.pbxuser
+!default.perspectivev3

packages/pointer_interceptor/pointer_interceptor/example/ios/Flutter/AppFrameworkInfo.plist

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>App</string>
+  <key>CFBundleIdentifier</key>
+  <string>io.flutter.flutter.app</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>App</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>1.0</string>
+  <key>MinimumOSVersion</key>
+  <string>11.0</string>
+</dict>
+</plist>

packages/pointer_interceptor/pointer_interceptor/example/ios/Flutter/Debug.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
+#include "Generated.xcconfig"

packages/pointer_interceptor/pointer_interceptor/example/ios/Flutter/Release.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
+#include "Generated.xcconfig"

packages/pointer_interceptor/pointer_interceptor/example/ios/Podfile

@@ -0,0 +1,41 @@
+# Uncomment this line to define a global platform for your project
+# platform :ios, '11.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_ios_podfile_setup
+
+target 'Runner' do
+  use_frameworks!
+  use_modular_headers!
+
+  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_ios_build_settings(target)
+  end
+end