fix: input mobile -> Android (#9767)

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/android/app/src/main/kotlin/com/carriez/flutter_hbb/InputService.kt

@@ -280,20 +280,20 @@ class InputService : AccessibilityService() {
 
         var textToCommit: String? = null
 
-        if (keyboardMode == KeyboardMode.Legacy) {
+        // [down] indicates the key's state(down or up).
-            if (keyEvent.hasChr() && keyEvent.getDown()) {
+        // [press] indicates a click event(down and up).
+        // https://github.com/rustdesk/rustdesk/blob/3a7594755341f023f56fa4b6a43b60d6b47df88d/flutter/lib/models/input_model.dart#L688
+        if (keyEvent.hasSeq()) {
+            textToCommit = keyEvent.getSeq()
+        } else if (keyboardMode == KeyboardMode.Legacy) {
+            if (keyEvent.hasChr() && (keyEvent.getDown() || keyEvent.getPress())) {
                 val chr = keyEvent.getChr()
                 if (chr != null) {
                     textToCommit = String(Character.toChars(chr))
                 }
             }
         } else if (keyboardMode == KeyboardMode.Translate) {
-            if (keyEvent.hasSeq() && keyEvent.getDown()) {
+        } else {
-                val seq = keyEvent.getSeq()
-                if (seq != null) {
-                    textToCommit = seq
-                }
-            }
         }
 
         Log.d(logTag, "onKeyEvent $keyEvent textToCommit:$textToCommit")
@@ -320,6 +320,10 @@ class InputService : AccessibilityService() {
                     } else {
                         ke?.let { event ->
                             inputConnection.sendKeyEvent(event)
+                            if (keyEvent.getPress()) {
+                                val actionUpEvent = KeyEventAndroid(KeyEventAndroid.ACTION_UP, event.keyCode)
+                                inputConnection.sendKeyEvent(actionUpEvent)
+                            }
                         }
                     }
                 }
@@ -333,6 +337,10 @@ class InputService : AccessibilityService() {
                     for (item in possibleNodes) {
                         val success = trySendKeyEvent(event, item, textToCommit)
                         if (success) {
+                            if (keyEvent.getPress()) {
+                                val actionUpEvent = KeyEventAndroid(KeyEventAndroid.ACTION_UP, event.keyCode)
+                                trySendKeyEvent(actionUpEvent, item, textToCommit)
+                            }
                             break
                         }
                     }

flutter/android/app/src/main/kotlin/com/carriez/flutter_hbb/KeyboardKeyEventMapper.kt

@@ -31,14 +31,12 @@ object KeyEventConverter {
         }
 
         var action = 0
-        if (keyEventProto.getDown()) {
+        if (keyEventProto.getDown() || keyEventProto.getPress()) {
             action = KeyEvent.ACTION_DOWN
         } else {
             action = KeyEvent.ACTION_UP
         }
 
-        // FIXME: The last parameter is the repeat count, not modifiers ?
-        // https://developer.android.com/reference/android/view/KeyEvent#KeyEvent(long,%20long,%20int,%20int,%20int)
         return KeyEvent(0, 0, action, chrValue, 0, modifiers)
     }
 

flutter/lib/mobile/pages/remote_page.dart

@@ -560,6 +560,14 @@ class _RemotePageState extends State<RemotePage> with WidgetsBindingObserver {
                       controller: _textController,
                       // trick way to make backspace work always
                       keyboardType: TextInputType.multiline,
+                      // `onChanged` may be called depending on the input method if this widget is wrapped in
+                      // `Focus(onKeyEvent: ..., child: ...)`
+                      // For `Backspace` button in the soft keyboard:
+                      // en/fr input method: 
+                      //      1. The button will not trigger `onKeyEvent` if the text field is not empty.
+                      //      2. The button will trigger `onKeyEvent` if the text field is empty.
+                      // ko/zh/ja input method: the button will trigger `onKeyEvent`
+                      //                     and the event will not popup if `KeyEventResult.handled` is returned.
                       onChanged: handleSoftKeyboardInput,
                     ),
             ),