add USB support

Android/README.md

@@ -6,9 +6,10 @@ Android Microphone Project (Android Application folder)
 
 ### Structure
 
-Three major threads:  
+Four major threads:  
 * UI thread  
 * Bluetooth client thread  
+* USB tcp client thread  
 * Audio recorder thread  
 
 ------
@@ -27,6 +28,13 @@ Three major threads:
 * transfer stored audio data  
 * cancel connection  
 
+#### USB Thread  
+
+* check if USB tethering is enabled  
+* connect to server based on input address  
+* transfer stored audio data  
+* cancel connection  
+
 #### Audio Thread  
 
 * check for permission  
@@ -40,4 +48,6 @@ Three major threads:
 
 This is the first Android application I write in Kotlin. The bluetooth part is basically the same as the Java applications I wrote before. However, Kotlin appears to be cleaner and shorter in length. A notable difference is that Kotlin uses `coroutines` to replace `AsyncTask` in Java, which I think is better. Another difference is that Kotlin is strict with `null` values and provide many ways to check them.  
 
-A drawback of this application is that it won't be able to run in background. So when connected, your application will force the screen on and will close connection whenever the app is put into background. A possible fix is to create [Background Services](https://developer.android.com/training/run-background-service/create-service) instead of threads I'm currently using. However, that requires much efforts in learning, and the communication with main activity is especially complex. I will leave it like that.
+A drawback of this application is that it won't be able to run in background. So when connected, your application will force the screen on and will close connection whenever the app is put into background. A possible fix is to create [Background Services](https://developer.android.com/training/run-background-service/create-service) instead of threads I'm currently using. However, that requires much efforts in learning, and the communication with main activity is especially complex. I will leave it like that.  
+
+USB communication is achieved by enabling USB tethering. In this case, the network through PC can be detected by Android. By establishing a TCP socket, the device can communicate with PC app through USB.  

Android/app/build.gradle

@@ -11,8 +11,8 @@ android {
         applicationId "com.example.microphone"
         minSdkVersion 19
         targetSdkVersion 30
-        versionCode 2
-        versionName "1.1"
+        versionCode 3
+        versionName "1.2"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }

Android/app/src/main/AndroidManifest.xml

@@ -4,15 +4,15 @@
     <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.INTERNET" />
 
     <application
         android:allowBackup="true"
         android:icon="@drawable/icon"
         android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/Theme.Microphone">
-        <activity android:name=".MainActivity"
-            android:screenOrientation="portrait">
+        <activity android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

Android/app/src/main/java/com/example/microphone/BluetoothHelper.kt

@@ -222,6 +222,6 @@ class BluetoothHelper(private val mActivity: MainActivity, private val mGlobalDa
     // check if current socket is valid and connected
     fun isSocketValid() : Boolean
     {
-        return !(mSocket == null || mSocket?.isConnected == false)
+        return mSocket?.isConnected == true
     }
 }

Android/app/src/main/java/com/example/microphone/MainActivity.kt

@@ -1,13 +1,17 @@
 package com.example.microphone
 
+import android.content.DialogInterface
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.text.InputType
 import android.util.Log
 import android.view.View
 import android.view.WindowManager
 import android.widget.Button
+import android.widget.EditText
 import android.widget.TextView
 import android.widget.Toast
+import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.widget.SwitchCompat
 import kotlinx.coroutines.*
 import java.lang.Exception
@@ -26,7 +30,10 @@ class GlobalState(
     var isBluetoothStarted : Boolean,
     var bluetoothShouldStop : Boolean,
     var isAudioStarted : Boolean,
-    var audioShouldStop : Boolean
+    var audioShouldStop : Boolean,
+    var isUSBStarted : Boolean,
+    var usbShouldStop : Boolean,
+    var isUSBAddressSet : Boolean
 )
 
 // global data structure
@@ -69,13 +76,18 @@ class MainActivity : AppCompatActivity()
     private val mUIScope = CoroutineScope(Dispatchers.Main)
     private var mJobBluetooth : Job? = null
     private var mJobAudio : Job? = null
+    private var mJobUSB : Job? = null
 
     private lateinit var mLogTextView : TextView
 
     private var helperBluetooth : BluetoothHelper? = null
     private var helperAudio : AudioHelper? = null
+    private var helperUSB : USBHelper? = null
 
     private val mGlobalState = GlobalState(
+        false,
+        false,
+        false,
         false,
         false,
         false,
@@ -86,6 +98,7 @@ class MainActivity : AppCompatActivity()
 
     private var threadBth : Thread? = null
     private var threadAio : Thread? = null
+    private var threadUSB : Thread? = null
 
     override fun onCreate(savedInstanceState: Bundle?)
     {
@@ -99,41 +112,53 @@ class MainActivity : AppCompatActivity()
 
     override fun onStop() {
         super.onStop()
-        mGlobalState.bluetoothShouldStop = true
-        mGlobalState.audioShouldStop = true
-        threadBth?.join()
-        threadAio?.join()
-        helperBluetooth?.clean()
-        helperAudio?.clean()
+        clean()
     }
 
     override fun onResume() {
         super.onResume()
         findViewById<Button>(R.id.bth_connect).setText(R.string.turn_on_bth)
+        findViewById<Button>(R.id.usb_connect).setText(R.string.turn_on_usb)
         findViewById<SwitchCompat>(R.id.audio_switch).isChecked = false
         mGlobalState.isBluetoothStarted = false
         mGlobalState.isAudioStarted = false
+        mGlobalState.isUSBStarted = false
     }
 
     override fun onPause() {
         super.onPause()
         mLogTextView.text = "" // clear log messages on pause
+        clean()
+    }
+
+    fun clean()
+    {
         mGlobalState.bluetoothShouldStop = true
         mGlobalState.audioShouldStop = true
+        mGlobalState.usbShouldStop = true
         threadBth?.join()
         threadAio?.join()
+        threadUSB?.join()
         helperBluetooth?.clean()
         helperAudio?.clean()
+        helperUSB?.clean()
+        if(mJobUSB?.isActive == true) mJobUSB?.cancel()
+        if(mJobBluetooth?.isActive == true) mJobBluetooth?.cancel()
+        if(mJobAudio?.isActive == true) mJobAudio?.cancel()
     }
 
     // onclick for bluetooth button
     fun onButtonBluetooth(view : View)
     {
         if(!mGlobalState.isBluetoothStarted)
         {
+            if(isConnected())
+            {
+                showToastMessage("Already connected")
+                return
+            }
             val activity = this
             if(mJobBluetooth?.isActive == true) return
-            this.showToastMessage("Starting bluetooth...")
             Log.d(mLogTag, "onButtonBluetooth [start]")
             mGlobalData.reset() // reset global data to store most recent audio
             // launch a coroutine to prepare bluetooth helper object and start thread
@@ -150,8 +175,13 @@ class MainActivity : AppCompatActivity()
                         {
                             activity.addLogMessage("Error: " + e.message)
                         }
+                        cancel()
                         null
                     }
+                    withContext(Dispatchers.Main)
+                    {
+                        activity.showToastMessage("Starting bluetooth...")
+                    }
                     // try to connect
                     if(helperBluetooth?.connect() == true)
                     {
@@ -182,17 +212,17 @@ class MainActivity : AppCompatActivity()
                             Thread.sleep(1)
                         }
                     }
-                    threadBth?.start()
-
                     // update UI if success start
-                    if(helperBluetooth != null && threadBth?.isAlive == true)
+                    if(helperBluetooth?.isSocketValid() == true)
                     {
                         withContext(Dispatchers.Main)
                         {
                             (view as Button).setText(R.string.turn_off_bth)
                         }
                         mGlobalState.isBluetoothStarted = true
                     }
+
+                    threadBth?.start()
                 }
             }
         }
@@ -210,12 +240,120 @@ class MainActivity : AppCompatActivity()
             }
             helperBluetooth?.clean()
             helperBluetooth = null
-            threadBth = null
             (view as Button).setText(R.string.turn_on_bth)
             mGlobalState.isBluetoothStarted = false
         }
     }
 
+    // onclick for USB button
+    fun onButtonUSB(view : View)
+    {
+        if(!mGlobalState.isUSBStarted)
+        {
+            if(isConnected())
+            {
+                showToastMessage("Already connected")
+                return
+            }
+            val activity = this
+            if(mJobUSB?.isActive == true) return
+            Log.d(mLogTag, "onButtonUSB [start]")
+            mGlobalData.reset() // reset global data to store most recent audio
+            // launch a coroutine to prepare bluetooth helper object and start thread
+            mJobUSB = mUIScope.launch {
+                withContext(Dispatchers.Default)
+                {
+                    mGlobalState.usbShouldStop = false
+                    helperUSB?.clean()
+                    // create object
+                    helperUSB = try {
+                        USBHelper(activity, mGlobalData)
+                    } catch (e : IllegalArgumentException){
+                        withContext(Dispatchers.Main)
+                        {
+                            activity.addLogMessage("Error: " + e.message)
+                        }
+                        cancel()
+                        null
+                    }
+                    // get target IP address
+                    withContext(Dispatchers.Main)
+                    {
+                        getIpAddress()
+                    }
+                    while(!mGlobalState.usbShouldStop && !mGlobalState.isUSBAddressSet)
+                    {
+                        try {
+                            delay(200)
+                        } catch (e : CancellationException) {break}
+                    }
+                    withContext(Dispatchers.Main)
+                    {
+                        activity.showToastMessage("Starting USB client...")
+                    }
+                    // try to connect
+                    if(helperUSB?.connect() == true)
+                    {
+                        withContext(Dispatchers.Main)
+                        {
+                            activity.showToastMessage("Device connected")
+                            activity.addLogMessage("Connected Device Information\n${helperUSB?.getConnectedDeviceInfo()}")
+                        }
+                        Log.d(mLogTag, "onButtonUSB [connect]")
+                    }
+                    // define and start the thread
+                    threadUSB = Thread{
+                        while (!mGlobalState.usbShouldStop) {
+                            if (helperUSB?.isSocketValid() == true) // check if socket is disconnected
+                                helperUSB?.sendData()
+                            else {
+                                // if not valid, disconnect the device
+                                runOnUiThread {
+                                    activity.addLogMessage("Device disconnected")
+                                    mGlobalState.isUSBStarted = false
+                                    helperUSB?.clean()
+                                    helperUSB = null
+                                    threadUSB = null
+                                    (view as Button).setText(R.string.turn_on_usb)
+                                }
+                                break
+                            }
+                            Thread.sleep(1)
+                        }
+                    }
+                    // update UI if success start
+                    if(helperUSB?.isSocketValid() == true)
+                    {
+                        withContext(Dispatchers.Main)
+                        {
+                            (view as Button).setText(R.string.turn_off_usb)
+                        }
+                        mGlobalState.isUSBStarted = true
+                    }
+
+                    threadUSB?.start()
+                }
+            }
+        }
+        else
+        {
+            mGlobalState.usbShouldStop = true
+            this.showToastMessage("Stopping USB client...")
+            Log.d(mLogTag, "onButtonUSB [stop]")
+            ignore { threadUSB?.join(1000) }
+            threadUSB = null
+            if(helperUSB?.disconnect() == true)
+            {
+                this.showToastMessage("Device disconnected")
+                this.addLogMessage("Device disconnected successfully")
+            }
+            helperUSB?.clean()
+            helperUSB = null
+            (view as Button).setText(R.string.turn_on_usb)
+            mGlobalState.isUSBStarted = false
+        }
+    }
+
     // on change for microphone switch
     // basically similar to bluetooth function
     fun onSwitchMic(view : View)
@@ -295,14 +433,43 @@ class MainActivity : AppCompatActivity()
     }
 
     // helper function to show toast message
-    fun showToastMessage(message : String)
+    private fun showToastMessage(message : String)
     {
         Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
     }
 
     // helper function to append log message to textview
-    fun addLogMessage(message : String)
+    private fun addLogMessage(message : String)
     {
         mLogTextView.append(message + "\n")
     }
+
+    private fun isConnected() : Boolean
+    {
+        return mGlobalState.isUSBStarted || mGlobalState.isBluetoothStarted
+    }
+
+    private fun getIpAddress()
+    {
+        mGlobalState.isUSBAddressSet = false
+        val builder =  AlertDialog.Builder(this)
+        builder.setTitle("PC IP Address")
+        val input = EditText(this)
+        input.setText("192.168.")
+        input.inputType = InputType.TYPE_CLASS_PHONE
+        builder.setView(input)
+        builder.setPositiveButton("OK"
+        ) { dialog, which ->
+            if(helperUSB?.setAddress(input.text.toString()) != true)
+                addLogMessage("Invalid address: ${input.text}")
+            mGlobalState.isUSBAddressSet = true
+        }
+        builder.setOnCancelListener {
+            mGlobalState.isUSBAddressSet = true
+        }
+        builder.setOnDismissListener {
+            mGlobalState.isUSBAddressSet = true
+        }
+        builder.show()
+    }
 }