TextField “onChanged” was called multi times when i use Chinese inputting mode!

[EdworldWang]

Steps to Reproduce

import 'package:flutter/material.dart';

class SearchInputWidget extends StatefulWidget {
  final String preInputText;
  final Function(String text) onSubmitted;

  const SearchInputWidget({
    @required this.onSubmitted,
    this.preInputText
  });

  @override
  State<StatefulWidget> createState() {
    return new _SearchInputWidgetState();
  }
}

class _SearchInputWidgetState extends State<SearchInputWidget> {
  bool showCancel = false;
  String inputText = "";

  @override
  void initState() {
    super.initState();
    this.inputText = (widget.preInputText != null ? widget.preInputText : "");

  }

  @override
  Widget build(BuildContext context) {
    print("searchInput build "+ this.inputText);
    TextEditingController inputController = TextEditingController.fromValue(TextEditingValue(
        text: inputText,  
        selection: TextSelection.fromPosition(TextPosition(
            affinity: TextAffinity.downstream,
            offset: '${inputText}'.length)
        )
    ));
    return new Container(
      //margin: EdgeInsets.only(left: 40, top: 40),
      alignment: Alignment(0, 0),
      height: 44,
      width: 300,
      decoration: new BoxDecoration(
        color: Colors.grey.shade200,
        borderRadius: BorderRadius.all(Radius.circular(12.0)),
        //border: new Border.all(width: 1, color: Colors.red),
      ),
      child: new TextField(
        //maxLines: 1,
        controller: inputController,
        maxLength: 30,
        cursorColor: Colors.black,
        style: TextStyle(fontSize: 16, color: Colors.black),
        onChanged: (text){
          print("searchInput onChanged "+ text);
          setState(() {
            print("searchInput setState "+ text);
            inputText = text;
            showCancel = (text.length > 0);
          });
        },
        onSubmitted: (text) {
          widget.onSubmitted != null && widget.onSubmitted(text);
        },
        decoration: InputDecoration(
          prefixIcon: Icon(
            Icons.search,
            color: Colors.black45,
            size: 24,
          ),
          suffixIcon: new Offstage(
            offstage: !showCancel,
            child: new IconButton(
                icon: Icon(
                  Icons.cancel,
                  color: Colors.black45,
                  size: 20,
                ),
                onPressed: _onClickClear),
          ),
          border: InputBorder.none,
          /*  fillColor: Colors.red,
                    filled: true,*/
          counterText: "", 
        ),
      ),
    );
  }
  void _onClickClear() {
    setState(() {
      inputText = "";
      showCancel = false;
    });
  }
}

but the same code run well if i input in english inputting mode.

flutter: searchInput build
flutter: searchInput onChanged q
flutter: searchInput setState q
**Actual results:** <!-- what did you see? -->
when i input "q" in Chinese inputting mode,the text in the TextField is "qq",here is the log.
flutter: searchInput onChanged q
flutter: searchInput setState q
flutter: searchInput build q
flutter: searchInput onChanged qq
flutter: searchInput setState qq
flutter: searchInput build qq

[TahaTesser]

I can reproduce this issue on iOS but not Android

flutter: searchInput onChanged q
flutter: searchInput setState q
flutter: searchInput build q
flutter: searchInput onChanged qq
flutter: searchInput setState qq
flutter: searchInput build qq

flutter doctor -v

[✓] Flutter (Channel dev, 1.20.0-3.0.pre, on Mac OS X 10.15.5 19F101, locale
    en-GB)
    • Flutter version 1.20.0-3.0.pre at /Users/taha/Code/flutter_dev
    • Framework revision 0af027f805 (5 days ago), 2020-07-04 12:19:20 -0700
    • Engine revision a751393804
    • Dart version 2.9.0 (build 2.9.0-20.0.dev 22da8934ac)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
    • Android SDK at /Users/taha/Code/sdk
    • Platform android-30, build-tools 30.0.0
    • ANDROID_HOME = /Users/taha/Code/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.5)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.5, Build version 11E608c
    • CocoaPods version 1.9.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 47.1.2
    • Dart plugin version 193.7361
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.46.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.12.1

[✓] Connected device (4 available)
    • SM M305F (mobile)      • 32003c30dc19668f          • android-arm64  •
      Android 10 (API 29)
    • Taha’s iPhone (mobile) • 00008020-001059882212002E • ios            • iOS
      13.5.1
    • Web Server (web)       • web-server                • web-javascript •
      Flutter Tools
    • Chrome (web)           • chrome                    • web-javascript •
      Google Chrome 83.0.4103.116

• No issues found!

@EdworldWang
Can you please confirm you experience on iOS and not on Android?
Thank you

[ihdream72]

is same problem in Korean input mode.

[FrunkPiano]

try my flutter textfield plugin custom_text_field
soleve the problem

[TahaTesser]

This doesn't look like a bug from the Framework side,
Engine calls userUpdateTextEditingValue two times

flutter/packages/flutter/lib/src/services/text_input.dart

Line 985 in ffcd32e

void userUpdateTextEditingValue(TextEditingValue value, SelectionChangedCause cause);

Since I don't have experience with Objective-c, I can't fix it as of now