EditableText should not update textinput style when the textinput is … (#47904)

packages/flutter/lib/src/widgets/editable_text.dart

@@ -1172,13 +1172,17 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     }
     if (widget.style != oldWidget.style) {
       final TextStyle style = widget.style;
-      _textInputConnection?.setStyle(
-        fontFamily: style.fontFamily,
-        fontSize: style.fontSize,
-        fontWeight: style.fontWeight,
-        textDirection: _textDirection,
-        textAlign: widget.textAlign,
-      );
+      // The _textInputConnection will pick up the new style when it attaches in
+      // _openInputConnection.
+      if (_textInputConnection != null && _textInputConnection.attached) {
+        _textInputConnection.setStyle(
+          fontFamily: style.fontFamily,
+          fontSize: style.fontSize,
+          fontWeight: style.fontWeight,
+          textDirection: _textDirection,
+          textAlign: widget.textAlign,
+        );
+      }
     }
   }
 

packages/flutter/test/widgets/editable_text_test.dart

@@ -513,6 +513,89 @@ void main() {
     expect(handles[1].localToGlobal(Offset.zero), const Offset(197.0, 17.0));
   });
 
+  testWidgets('can update style of previous activated EditableText', (WidgetTester tester) async {
+    final Key key1 = UniqueKey();
+    final Key key2 = UniqueKey();
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(devicePixelRatio: 1.0),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: FocusScope(
+            node: focusScopeNode,
+            autofocus: true,
+            child: Column(
+              children: <Widget>[
+                EditableText(
+                  key: key1,
+                  controller: TextEditingController(),
+                  backgroundCursorColor: Colors.grey,
+                  focusNode: focusNode,
+                  style: const TextStyle(fontSize: 9),
+                  cursorColor: cursorColor,
+                ),
+                EditableText(
+                  key: key2,
+                  controller: TextEditingController(),
+                  backgroundCursorColor: Colors.grey,
+                  focusNode: focusNode,
+                  style: const TextStyle(fontSize: 9),
+                  cursorColor: cursorColor,
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.byKey(key1));
+    await tester.showKeyboard(find.byKey(key1));
+    controller.text = 'test';
+    await tester.idle();
+    RenderBox renderEditable = tester.renderObject(find.byKey(key1));
+    expect(renderEditable.size.height, 9.0);
+    // Taps the other EditableText to deactivate the first one.
+    await tester.tap(find.byKey(key2));
+    await tester.showKeyboard(find.byKey(key2));
+    // Updates the style.
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(devicePixelRatio: 1.0),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: FocusScope(
+            node: focusScopeNode,
+            autofocus: true,
+            child: Column(
+              children: <Widget>[
+                EditableText(
+                  key: key1,
+                  controller: TextEditingController(),
+                  backgroundCursorColor: Colors.grey,
+                  focusNode: focusNode,
+                  style: const TextStyle(fontSize: 20),
+                  cursorColor: cursorColor,
+                ),
+                EditableText(
+                  key: key2,
+                  controller: TextEditingController(),
+                  backgroundCursorColor: Colors.grey,
+                  focusNode: focusNode,
+                  style: const TextStyle(fontSize: 9),
+                  cursorColor: cursorColor,
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+    renderEditable = tester.renderObject(find.byKey(key1));
+    expect(renderEditable.size.height, 20.0);
+    expect(tester.takeException(), null);
+  });
+
   testWidgets('Multiline keyboard with newline action is requested when maxLines = null', (WidgetTester tester) async {
     await tester.pumpWidget(
       MediaQuery(