[Fix] TextField maxLength wrong IME input behavior

Author: IIzzaya

Runtime/service/keyboard.cs

@@ -69,6 +69,8 @@ public bool imeRequired() {
             return true;
         }
 
+        bool isimeInput = false;
+
         public void OnGUI() {
             if (TouchScreenKeyboard.isSupported) {
                 return;
@@ -101,15 +103,24 @@ public void OnGUI() {
                     if (_validateCharacter(ch)) {
                         this._value = this._value.insert(new string(ch, 1));
                     }
-                } else if (!string.IsNullOrEmpty(Input.compositionString)) {
+                }
+                else if (!string.IsNullOrEmpty(Input.compositionString)) {
+                    this.isimeInput = true;
                     this._value = this._value.compose(Input.compositionString);
                 }
 
                 currentEvent.Use();
             }
 
             if (this._value != oldValue) {
-                Window.instance.run(() => { TextInput._updateEditingState(this._client, this._value); });
+                if (this.isimeInput) {
+                    var imeInput = this.isimeInput;
+                    Window.instance.run(() => { TextInput._updateEditingState(this._client, this._value, imeInput); });
+                    this.isimeInput = false;
+                }
+                else {
+                    Window.instance.run(() => { TextInput._updateEditingState(this._client, this._value); });
+                }
             }
         }
 

Runtime/service/text_formatter.cs

@@ -60,6 +60,10 @@ public LengthLimitingTextInputFormatter(int? maxLength) {
 
         public override TextEditingValue formatEditUpdate(TextEditingValue oldValue, TextEditingValue newValue) {
             if (this.maxLength != null && this.maxLength > 0 && newValue.text.Length > this.maxLength) {
+                if (Input.compositionString.Length > 0) {
+                    return newValue;
+                }
+
                 TextSelection newSelection = newValue.selection.copyWith(
                     baseOffset: Mathf.Min(newValue.selection.start, this.maxLength.Value),
                     extentOffset: Mathf.Min(newValue.selection.end, this.maxLength.Value)
@@ -72,9 +76,10 @@ public override TextEditingValue formatEditUpdate(TextEditingValue oldValue, Tex
                     composing: TextRange.empty
                 );
             }
+
             return newValue;
         }
-}
+    }
 
     static class Util {
         internal static TextEditingValue _selectionAwareTextManipulation(TextEditingValue value,

Runtime/service/text_input.cs

@@ -439,7 +439,7 @@ public interface TextSelectionDelegate {
     }
 
     public interface TextInputClient {
-        void updateEditingValue(TextEditingValue value);
+        void updateEditingValue(TextEditingValue value, bool imeInput);
 
         void performAction(TextInputAction action);
 
@@ -608,7 +608,7 @@ internal static void OnGUI() {
             }
         }
 
-        internal static void _updateEditingState(int client, TextEditingValue value) {
+        internal static void _updateEditingState(int client, TextEditingValue value, bool imeInput = false) {
             if (_currentConnection == null) {
                 return;
             }
@@ -617,7 +617,7 @@ internal static void _updateEditingState(int client, TextEditingValue value) {
                 return;
             }
 
-            _currentConnection._client.updateEditingValue(value);
+            _currentConnection._client.updateEditingValue(value, imeInput);
         }
 
         internal static void _performAction(int client, TextInputAction action) {

Runtime/widgets/editable_text.cs

@@ -341,7 +341,7 @@ public override void dispose() {
 
         TextEditingValue _lastKnownRemoteTextEditingValue;
 
-        public void updateEditingValue(TextEditingValue value) {
+        public void updateEditingValue(TextEditingValue value, bool imeInput) {
             if (value.text != this._value.text) {
                 this._hideSelectionOverlayIfNeeded();
                 this._showCaretOnScreen();
@@ -352,7 +352,7 @@ public void updateEditingValue(TextEditingValue value) {
             }
 
             this._lastKnownRemoteTextEditingValue = value;
-            this._formatAndSetValue(value);
+            this._formatAndSetValue(value, imeInput);
 
             this._stopCursorTimer(resetCharTicks: false);
             this._startCursorTimer();
@@ -723,8 +723,8 @@ public IPromise<bool> didPushRoute(string route) {
             return Promise<bool>.Resolved(false);
         }
 
-        void _formatAndSetValue(TextEditingValue value) {
-            var textChanged = this._value?.text != value?.text;
+        void _formatAndSetValue(TextEditingValue value, bool imeInput = false) {
+            var textChanged = this._value?.text != value?.text || imeInput;
             if (textChanged && this.widget.inputFormatters != null && this.widget.inputFormatters.isNotEmpty()) {
                 foreach (var formatter in this.widget.inputFormatters) {
                     value = formatter.formatEditUpdate(this._value, value);