From 324fe201b0231fcc39fff8c99fee1b22425c4bc0 Mon Sep 17 00:00:00 2001
From: Matt Carroll <matthew-carroll@users.noreply.github.com>
Date: Mon, 19 Aug 2019 15:49:32 -0700
Subject: [PATCH] Add handling of 'TextInput.clearClient' message from platform
 to framework (#35054). (#35100)

---
 .../flutter/lib/src/services/text_input.dart  | 18 +++++++--
 .../test/services/text_input_test.dart        | 39 +++++++++++++++++++
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/packages/flutter/lib/src/services/text_input.dart b/packages/flutter/lib/src/services/text_input.dart
index 0a95f75877e..0d5975aafdb 100644
--- a/packages/flutter/lib/src/services/text_input.dart
+++ b/packages/flutter/lib/src/services/text_input.dart
@@ -632,7 +632,7 @@ abstract class TextInputClient {
 /// See also:
 ///
 ///  * [TextInput.attach]
-class TextInputConnection {
+class TextInputConnection with ChangeNotifier {
   TextInputConnection._(this._client)
     : assert(_client != null),
       _id = _nextId++;
@@ -667,12 +667,19 @@ class TextInputConnection {
   void close() {
     if (attached) {
       SystemChannels.textInput.invokeMethod<void>('TextInput.clearClient');
-      _clientHandler
-        .._currentConnection = null
-        .._scheduleHide();
+      _onConnectionClosed();
+      _clientHandler._scheduleHide();
     }
     assert(!attached);
   }
+
+  /// Clear out the current text input connection.
+  ///
+  /// Call this method when the current text input connection has cleared.
+  void _onConnectionClosed() {
+    _clientHandler._currentConnection = null;
+    notifyListeners();
+  }
 }
 
 TextInputAction _toTextInputAction(String action) {
@@ -753,6 +760,9 @@ class _TextInputClientHandler {
       case 'TextInputClient.updateFloatingCursor':
         _currentConnection._client.updateFloatingCursor(_toTextPoint(_toTextCursorAction(args[1]), args[2]));
         break;
+      case 'TextInputClient.onConnectionClosed':
+        _currentConnection._onConnectionClosed();
+        break;
       default:
         throw MissingPluginException();
     }
diff --git a/packages/flutter/test/services/text_input_test.dart b/packages/flutter/test/services/text_input_test.dart
index ee9192c51cc..80651ed9dec 100644
--- a/packages/flutter/test/services/text_input_test.dart
+++ b/packages/flutter/test/services/text_input_test.dart
@@ -85,5 +85,44 @@ void main() {
       expect(signed.hashCode == signedDecimal.hashCode, false);
       expect(decimal.hashCode == signedDecimal.hashCode, false);
     });
+
+    test('The framework TextInputConnection closes when the platform loses its input connection', () async {
+      // Assemble a TextInputConnection so we can verify its change in state.
+      final TextInputClient client = NoOpTextInputClient();
+      const TextInputConfiguration configuration = TextInputConfiguration();
+      final TextInputConnection textInputConnection = TextInput.attach(client, configuration);
+
+      // Verify that TextInputConnection think its attached to a client. This is
+      // an intermediate verification of expected state.
+      expect(textInputConnection.attached, true);
+
+      // Pretend that the platform has lost its input connection.
+      final ByteData messageBytes = const JSONMessageCodec().encodeMessage(
+          <String, dynamic>{
+            'args': <dynamic>[1],
+            'method': 'TextInputClient.onConnectionClosed',
+          }
+      );
+      defaultBinaryMessenger.handlePlatformMessage(
+        'flutter/textinput',
+        messageBytes,
+        (ByteData _) {},
+      );
+
+      // Verify that textInputConnection no longer think its attached to an input
+      // connection. This is the critical verification of this test.
+      expect(textInputConnection.attached, false);
+    });
   });
 }
+
+class NoOpTextInputClient extends TextInputClient {
+  @override
+  void performAction(TextInputAction action) {}
+
+  @override
+  void updateEditingValue(TextEditingValue value) {}
+
+  @override
+  void updateFloatingCursor(RawFloatingCursorPoint point) {}
+}
\ No newline at end of file