Fix/android voice call (#16180)

* fix(android): handle missing audio permission in voice calls

- Avoid stop errors when voice capture was never started
- Dispatch voice call error dialogs on the main thread
- Explain how to enable Audio capture on the Screen share page

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

* fix(android): restore audio after failed voice call switches

* fix: translations

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

* fix: translatin

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

* fix(i18n): match UI label capitalization in translated messages

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

---------

Signed-off-by: fufesou <linlong1266@gmail.com>
Co-authored-by: RustDesk <71636191+rustdesk@users.noreply.github.com>

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

@@ -51,6 +51,7 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
     private var minBufferSize = 0
     private var audioRecordStat = false
     private var audioThread: Thread? = null
+    private var playbackCapturePending = false
 
     @RequiresApi(Build.VERSION_CODES.M)
     fun createAudioRecorder(inVoiceCall: Boolean, mediaProjection: MediaProjection?): Boolean {
@@ -193,6 +194,17 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
         return audioRecorder?.audioSource == MediaRecorder.AudioSource.VOICE_COMMUNICATION
     }
 
+    fun getVoiceCallStartError(): String {
+        return if (ActivityCompat.checkSelfPermission(
+            context,
+            Manifest.permission.RECORD_AUDIO
+        ) != PackageManager.PERMISSION_GRANTED) {
+            "To start a voice call, enable \"Audio capture\" on the \"Screen share\" page."
+        } else {
+            "Failed to start voice call."
+        }
+    }
+
     fun onVoiceCallStarted(mediaProjection: MediaProjection?): Boolean {
         if (!isSupportVoiceCall()) {
             return false
@@ -220,6 +232,7 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
             if (it.getAudioSource() == MediaRecorder.AudioSource.VOICE_COMMUNICATION) {
                 return true
             }
+            playbackCapturePending = true
         }
         audioRecordStat = false
         audioThread?.join()
@@ -234,11 +247,10 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
 
     @RequiresApi(Build.VERSION_CODES.M)
     fun switchOutVoiceCall(mediaProjection: MediaProjection?): Boolean {
-        audioRecorder?.let {
-            if (it.getAudioSource() != MediaRecorder.AudioSource.VOICE_COMMUNICATION) {
-                return true
-            }
+        if (!isVoiceCallActive() && !playbackCapturePending) {
+            return true
         }
+        playbackCapturePending = true
         audioRecordStat = false
         audioThread?.join()
 
@@ -246,7 +258,11 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
             Log.e(logTag, "createAudioRecorder fail")
             return false
         }
-        return startAudioRecorder()
+        val started = startAudioRecorder()
+        if (started) {
+            playbackCapturePending = false
+        }
+        return started
     }
 
     fun tryReleaseAudio() {
@@ -256,6 +272,7 @@ class AudioRecordHandle(private var context: Context, private var isVideoStart:
         audioRecordStat = false
         audioThread?.join()
         audioThread = null
+        playbackCapturePending = false
     }
 
     fun destroy() {

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

@@ -969,7 +969,7 @@ class MainActivity : FlutterActivity() {
             flutterMethodChannel?.invokeMethod("msgbox", mapOf(
                 "type" to "custom-nook-nocancel-hasclose-error",
                 "title" to "Voice call",
-                "text" to "Failed to start voice call."))
+                "text" to audioRecordHandle.getVoiceCallStartError()))
         } else {
             Log.d(logTag, "onVoiceCallStarted success")
         }

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

@@ -153,19 +153,13 @@ class MainService : Service() {
                         } else {
                             if (!switchOutVoiceCall()) {
                                 Log.e(logTag, "switchOutVoiceCall fail")
-                                MainActivity.flutterMethodChannel?.invokeMethod("msgbox", mapOf(
-                                    "type" to "custom-nook-nocancel-hasclose-error",
-                                    "title" to "Voice call",
-                                    "text" to "Failed to switch out voice call."))
+                                showVoiceCallError("Failed to switch out voice call.")
                             }
                         }
                     } else {
                         if (!switchToVoiceCall()) {
                             Log.e(logTag, "switchToVoiceCall fail")
-                            MainActivity.flutterMethodChannel?.invokeMethod("msgbox", mapOf(
-                                "type" to "custom-nook-nocancel-hasclose-error",
-                                "title" to "Voice call",
-                                "text" to "Failed to switch to voice call."))
+                            showVoiceCallError(audioRecordHandle.getVoiceCallStartError())
                         }
                     }
                 } catch (e: JSONException) {
@@ -507,6 +501,15 @@ class MainService : Service() {
         }
     }
 
+    private fun showVoiceCallError(message: String) {
+        Handler(Looper.getMainLooper()).post {
+            MainActivity.flutterMethodChannel?.invokeMethod("msgbox", mapOf(
+                "type" to "custom-nook-nocancel-hasclose-error",
+                "title" to "Voice call",
+                "text" to message))
+        }
+    }
+
     @Synchronized
     private fun startMicrophoneCapture(startAudio: () -> Boolean): Boolean {
         if (!setMicrophoneForegroundService(true)) {