• Software EV3-G recommanded (not Classromm, Inventor, etc)
• PC version LME-EV3_Full-setup_1.4.5_en-US_WIN32.exe from here
• Mac version (prior to 10.14) LME-EV3_Full-setup_1.4.3_en-US_OSX.dmg from here
• Software for renaming Brick, file access, writing control programs
• Great tutorial site here
• Overview: User Guide -- LMSUser_Guide_LEGO_MINDSTORMS_EV3_11_Tablet_ENUS.pdf
• Motors and Sensors -- EV3-Motors-Sensors-Explained.pdf

• Name the EV3 Brick (via Brick or EV3-G)
• Enable Bluetooth in EV3 brick
• Pair with computer (for EV3-G software)
• Pair with Android (for your app)
• Android (iOS) LEGO® MINDSTORMS® Commander

• Bluetooth Remote Control
• Complicated Layout and Navigaion
• Motor Control
• Sensor Control
• Sound Control
• File Control

• Setting up Bluetooth.
• Finding devices that are either paired or available in the local area.
• Connecting devices.
• Transferring data between devices.

• BluetoothAdapter
• BluetoothClass
• BluetoothDevice
• BluetoothSocket
• BluetoothServiceSocket

• Android turn on Bluetooth
• Pairing two devices
• Connect

• 1. Add user-permission to AndroidManifest.xml
• 2. New after Android 12 -- in app request app permissions
• 3. Get a list of paired devices from the Bluetooth hardware/software stack.
• 4. Initiate an RFCOMM connection to the target device.

    <!-- The following code snippet demonstrates how to declare Bluetooth-related permissions
in your app if it targets Android 12 or higher: -->
    <!-- Needed only if your app looks for Bluetooth devices.
             If your app doesn't use Bluetooth scan results to derive physical
             location information, you can strongly assert that your app
             doesn't derive physical location. -->
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />

    <!-- Needed only if your app communicates with already-paired Bluetooth devices. -->
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

<string name="menu_first">1. Grant Permission	

	vv_tvOut1
	vv_tvOut2

 protected void onCreate(Bundle savedInstanceState) {
...
        // Need grant permission once per install
        cpf_checkBTPermissions();
...
    public boolean onOptionsItemSelected(MenuItem menuItem) {
        switch (menuItem.getItemId()) {
            case R.id.menu_first: cpf_requestBTPermissions();
	...		

    private void cpf_checkBTPermissions() {
        if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.BLUETOOTH_SCAN) == PackageManager.PERMISSION_GRANTED) {
            binding.vvTvOut1.setText("BLUETOOTH_SCAN already granted.\n");
        }
        else {
            binding.vvTvOut1.setText("BLUETOOTH_SCAN NOT granted.\n");
        }
        if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_DENIED) {
            binding.vvTvOut2.setText("BLUETOOTH_CONNECT NOT granted.\n");
        }
        else {
            binding.vvTvOut2.setText("BLUETOOTH_CONNECT already granted.\n");
        }
    }

    // https://www.geeksforgeeks.org/android-how-to-request-permissions-in-android-application/
    private void cpf_requestBTPermissions() {
        // We can give any value but unique for each permission.
        final int BLUETOOTH_SCAN_CODE = 100;
        final int BLUETOOTH_CONNECT_CODE = 101;

        if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.BLUETOOTH_SCAN) == PackageManager.PERMISSION_DENIED) {
                ActivityCompat.requestPermissions(MainActivity.this,
                        new String[]{Manifest.permission.BLUETOOTH_SCAN},
                        BLUETOOTH_SCAN_CODE);
        }
        else {
            Toast.makeText(MainActivity.this,
                    "BLUETOOTH_SCAN already granted", Toast.LENGTH_SHORT) .show();
        }

        if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_DENIED) {
                ActivityCompat.requestPermissions(MainActivity.this,
                        new String[]{Manifest.permission.BLUETOOTH_CONNECT},
                        BLUETOOTH_CONNECT_CODE);
        }
        else {
            Toast.makeText(MainActivity.this,
                    "BLUETOOTH_CONNECT already granted", Toast.LENGTH_SHORT) .show();
        }
    }

<string name="menu_second">2. Search BT List
<string name="menu_third">3. Connect to EV3

...
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import java.util.Iterator;
import java.util.Set;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {
    // BT Variables
    private final String CV_ROBOTNAME = "EV3A";
    private BluetoothAdapter cv_btInterface = null;
    private Set<BluetoothDevice> cv_pairedDevices = null;
    private BluetoothDevice cv_btDevice = null;
    private BluetoothSocket cv_btSocket = null;
...
    @Override
    public boolean onOptionsItemSelected(MenuItem menuItem) {
        switch (menuItem.getItemId()) {
            case R.id.menu_first: cpf_requestBTPermissions();
                return true;
            case R.id.menu_second: cv_btDevice = cpf_locateInPairedBTList(CV_ROBOTNAME);
                return true;
            case R.id.menu_third: cpf_connectToEV3(cv_btDevice);
                return true;
            default:
                return super.onOptionsItemSelected(menuItem);
        }
    }

    // Modify from chap14, pp390 findRobot()
    private BluetoothDevice cpf_locateInPairedBTList(String name) {
        BluetoothDevice lv_bd = null;
        try {
            cv_btInterface = BluetoothAdapter.getDefaultAdapter();
            cv_pairedDevices = cv_btInterface.getBondedDevices();
            Iterator<BluetoothDevice> lv_it = cv_pairedDevices.iterator();
            while (lv_it.hasNext())  {
                lv_bd = lv_it.next();
                if (lv_bd.getName().equalsIgnoreCase(name)) {
                    binding.vvTvOut1.setText(name + " is in paired list");
                    return lv_bd;
                }
            }
            binding.vvTvOut1.setText(name + " is NOT in paired list");
        }
        catch (Exception e) {
            binding.vvTvOut1.setText("Failed in findRobot() " + e.getMessage());
        }
        return null;
    }

    // Modify frmo chap14, pp391 connectToRobot()
    private void cpf_connectToEV3(BluetoothDevice bd) {
        try  {
            cv_btSocket = bd.createRfcommSocketToServiceRecord
                    (UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
            cv_btSocket.connect();
            binding.vvTvOut2.setText("Connect to " + bd.getName() + " at " + bd.getAddress());
        }
        catch (Exception e) {
            binding.vvTvOut2.setText("Error interacting with remote device [" +
                    e.getMessage() + "]");
        }
    }

}

...	
import java.io.InputStream;
import java.io.OutputStream;

public class MainActivity extends AppCompatActivity {
    //// HERE
    // Data stream to/from NXT bluetooth
    private InputStream cv_is = null;
    private OutputStream cv_os = null;
...

    @Override
    public boolean onOptionsItemSelected(MenuItem menuItem) {
...		
            case R.id.menu_fourth: cpf_EV3MoveMotor();
                return true;
            case R.id.menu_fifth: cpf_EV3PlayTone();
                return true;
            case R.id.menu_sixth: cpf_disconnFromEV3(cv_btDevice);
                return true;

    // Modify frmo chap14, pp391 connectToRobot()
    private void cpf_connectToEV3(BluetoothDevice bd) {
        try  {
            cv_btSocket = bd.createRfcommSocketToServiceRecord
                    (UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
            cv_btSocket.connect();

            //// HERE
            cv_is = cv_btSocket.getInputStream();
            cv_os = cv_btSocket.getOutputStream();
...

    private void cpf_disconnFromEV3(BluetoothDevice bd) {
        try {
            cv_btSocket.close();
            cv_is.close();
            cv_os.close();
            binding.vvTvOut2.setText(bd.getName() + " is disconnect " );
        } catch (Exception e) {
            binding.vvTvOut2.setText("Error in disconnect -> " + e.getMessage());
        }
    }

    // Communication Developer Kit Page 27
    // 4.2.2 Start motor B & C forward at power 50 for 3 rotation and braking at destination
    private void cpf_EV3MoveMotor() {
        try {
            byte[] buffer = new byte[20];       // 0x12 command length

            buffer[0] = (byte) (20-2);
            buffer[1] = 0;

            buffer[2] = 34;
            buffer[3] = 12;

            buffer[4] = (byte) 0x80;

            buffer[5] = 0;
            buffer[6] = 0;

            buffer[7] = (byte) 0xae;
            buffer[8] = 0;

            buffer[9] = (byte) 0x06;

            buffer[10] = (byte) 0x81;
            buffer[11] = (byte) 0x32;

            buffer[12] = 0;

            buffer[13] = (byte) 0x82;
            buffer[14] = (byte) 0x84;
            buffer[15] = (byte) 0x03;

            buffer[16] = (byte) 0x82;
            buffer[17] = (byte) 0xB4;
            buffer[18] = (byte) 0x00;

            buffer[19] = 1;

            cv_os.write(buffer);
            cv_os.flush();
        }
        catch (Exception e) {
            binding.vvTvOut1.setText("Error in MoveForward(" + e.getMessage() + ")");
        }
    }

    // 4.2.5 Play a 1Kz tone at level 2 for 1 sec.
    private void cpf_EV3PlayTone() {
...
    }

• Command size, Little Endian
• Message counter
• Byte 0: Telegram type -- 0x00 (response required), 0x80 (no response)
• Byte 1-N: command

• 0x00 or 0x80 command mode
• 0x02 or 0x04 replay
• 4.2.2 Start motor B & C forward at power 50 for 3 rotation and braking at destination

  a) final bytes
  1200xxxx800000AE000681320082840382B40001 
  bbbbmmmmtthhhhcccccccccccccccccccccccccc
  
  b) command
  opOUTPUT_STEP_SPEED		Opcode		
  LC0(LAYER_0)		Layer 0 – encoded as single byte constant
  LC0(MOTOR_A + MOTOR_B)	Motor B & C (motor list) encoded as single byte constant
  LC1(SPEED_50)			Speed 50% encoded as one constant byte to follow
  LC0(0)				No STEP1 i.e. full speed from beginning – encoded as single byte constant
  LC2(900)			STEP2 for 2.5 rotation (900 degrees) – encodes as two bytes to follow.
  LC2(180)			STEP3 for 0.5 rotation (180 degrees) for better precision at destination – encoded as two bytes to follow.
  LC0(BRAKE)			Brake (1) – encoded as single byte constant.
  
  c) command value
  0xae   opOUTPUT_STEP_SPEED		
  0x00   LC0(LAYER_0)
  0x06   LC0(MOTOR_A + MOTOR_B) motor DCBA in binary (0110)
  0x32   LC1(SPEED_50) (32)_{16}=(50)_{10}
  0x00   LC0(0)
  0x0384 LC2(900) (0x384)_{16}=(900)_{10}
  0x00b4 LC2(180) (0xb4)_{16}=(180)_{10}
  0x01   LC0(BRAKE) 
  
  d) command value format (13 bytes)
     0xae     opOUTPUT_STEP_SPEED		
     0x00     LC0(LAYER_0)
     0x06     LC0(MOTOR_A + MOTOR_B) motor DCBA in binary (0110)
  *  0x8132   LC1(SPEED_50) (32)_{16}=(50)_{10} 81->%
     0x00     LC0(0)
  ** 0x828403 LC2(900) (0x384)_{16}=(900)_{10} 82->val, little Endian
  ** 0x82B400 LC2(180) (0xb4)_{16}=(180)_{10}
     0x01     LC0(BRAKE) 
  
  e) header (16 bytes)
     0x80     direct command, no reply
     0x0000   Reservation (allocation) of global and local variables
     	
     0xae     opOUTPUT_STEP_SPEED		
     0x00     LC0(LAYER_0)
     0x06     LC0(MOTOR_A + MOTOR_B) motor DCBA in binary (0110)
  *  0x8132   LC1(SPEED_50) (32)_{16}=(50)_{10} 81->%
     0x00     LC0(0)
  ** 0x828403 LC2(900) (0x384)_{16}=(900)_{10} 82->val, little Endian
  ** 0x82B400 LC2(180) (0xb4)_{16}=(180)_{10}
     0x01     LC0(BRAKE) 
  
  e) header (18 bytes)
     0xxxxx   Message counter, Little Endian   	
     0x80     direct command, no reply
     0x0000   Reservation (allocation) of global and local variables
     	
     0xae     opOUTPUT_STEP_SPEED		
     0x00     LC0(LAYER_0)
     0x06     LC0(MOTOR_A + MOTOR_B) motor DCBA in binary (0110)
  *  0x8132   LC1(SPEED_50) (32)_{16}=(50)_{10} 81->%
     0x00     LC0(0)
  ** 0x828403 LC2(900) (0x384)_{16}=(900)_{10} 82->val, little Endian
  ** 0x82B400 LC2(180) (0xb4)_{16}=(180)_{10}
     0x01     LC0(BRAKE) 
  
  f) complte command to send
     0x1200   command size (18), hex (0x0012), Little Endian
     0xxxxx   Message counter, Little Endian   	
     0x80     direct command, no reply
     0x0000   Reservation (allocation) of global and local variables
     	
     0xae     opOUTPUT_STEP_SPEED		
     0x00     LC0(LAYER_0)
     0x06     LC0(MOTOR_A + MOTOR_B) motor DCBA in binary (0110)
  *  0x8132   LC1(SPEED_50) (32)_{16}=(50)_{10} 81->%
     0x00     LC0(0)
  ** 0x828403 LC2(900) (0x384)_{16}=(900)_{10} 82->val, Little Endian
  ** 0x82B400 LC2(180) (0xb4)_{16}=(180)_{10}
     0x01     LC0(BRAKE) 
  
  1200xxxx800000AE000681320082840382B40001 
  

• 4.2.5 Play a 1Kz tone at level 2 for 1 sec.

  0F00xxxx8000009401810282E80382E803
  	
  0x94   opSOUND		Opcode sound related
  0x01   LC0(TONE)	Command (TONE) encoded as single byte constant
  0x02   LC1(2)		Sound-level 2 encoded as one constant byte to follow
  0x03e8 LC2(1000)	Frequency 1000 Hz. encoded as two constant bytes to follow
  0x03e8 LC2(1000)	Duration 1000 mS. encoded as two constant bytes to follow
  
  0x0F00
  0xxxxx
  0x80
  0x0000
  0x94      opSOUND
  0x01      LC0(TONE)
  0x8102    LC1(2)
  0x82E803  LC2(1000)
  0x82E803  LC2(1000)
  

public class MyRecyclerViewData {
    private String mv_model;
    private String mv_os;
    private int mv_price;

    public MyRecyclerViewData(){
    }

    public MyRecyclerViewData(String model, String os, int price){
        mv_model = model;
        mv_os = os;
        mv_price = price;
    }

    public String getModel(){
        return this.mv_model;
    }

    public String getOS(){
        return this.mv_os;
    }

    public int getPrice(){
        return this.mv_price;
    }

    public void setModel(String model){
        mv_model = model;
    }

    public void setOS(String os){
        mv_os = os;
    }

    public void setPrice(int price){
        mv_price = price;
    }
}

...
    ArrayList<MyRecyclerViewData> lv_data;
...
        String[] lv_Model = {"iPad","Xoom","Playbook","TouchPad","Surface"};
        String[] lv_OS = {"iOS","Android","BlackBerry","WebOS","Windows"};
        int[] lv_Price = {499,799,499,499,449};

        lv_data = new ArrayList<>();
        for (int i=0; i < lv_Model.length; i++ ) {
            lv_data.add(new MyRecyclerViewData(lv_Model[i], lv_OS[i], lv_Price[i]));
        }

        lv_adapter = new MyRecyclerViewAdapter(lv_data);
...
	lv_data.add(1, new MyRecyclerViewData("New Model", "New OS", 123));
...
	lv_data.remove(2);

...
    private final ArrayList&MyRecyclerViewData> mv_data;	
...
    public MyRecyclerViewAdapter(ArrayList<MyRecyclerViewData> data) {
        mv_data = data;
    }
...
   public void onBindViewHolder(MyRecyclerViewAdapter.MyViewHolder holder, int position) {
        holder.cv_tvModel.setText(mv_data.get(position).getModel());
        holder.cv_tvOS.setText(mv_data.get(position).getOS());
        holder.cv_tvPrice.setText("$"+mv_data.get(position).getPrice());
...
        return mv_data.size();
...	

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <androidx.cardview.widget.CardView.   ##########
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:layout_marginVertical="16dp"
        android:layout_marginHorizontal="16dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        card_view:cardCornerRadius="4dp">

        <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="Medium Text"
                android:id="@+id/vv_tvModel"
                android:layout_marginLeft="25dp"
                android:layout_marginStart="25dp"
                android:layout_alignTop="@+id/vv_tvPrice"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceLarge"
                android:text="Large Text"
                android:id="@+id/vv_tvPrice"
                android:layout_alignParentTop="true"
                android:layout_alignParentRight="true"
                android:layout_alignParentEnd="true"
                android:background="@android:color/holo_green_light"
                android:layout_margin="10dp"
                android:padding="15dp"
                android:textColor="@android:color/background_light" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceSmall"
                android:text="Small Text"
                android:id="@+id/vv_tvOS"
                android:layout_alignBottom="@+id/vv_tvPrice"
                android:layout_alignLeft="@+id/vv_tvModel"
                android:layout_alignStart="@+id/vv_tvModel" />
        </RelativeLayout>

		</androidx.cardview.widget.CardView>
</RelativeLayout>

• Ad hoc code
• Open source library, here and here
• SDK -- SwipeRefreshLayout

• In layout.xml, wrap the view around SwipeRefreshLayout element
• Implement SwipeRefreshLayout.OnRefreshListener in MainActivity
• Override onRefresh() method
• Set setRefreshing(false) to hide the refresh icon

    implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/vv_tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/rc_strTitle"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.022" />

    
    <androidx.swiperefreshlayout.widget.SwipeRefreshLayout   ############
        android:id="@+id/vv_refresh"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/vv_rvList"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="24dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="32dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/vv_tvTitle" />

		</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/vv_fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="24dp"
        android:clickable="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:srcCompat="@android:drawable/ic_input_add" />

</androidx.constraintlayout.widget.ConstraintLayout>

• Implements SwipeRefreshLayout.OnRefreshListener
• Override onRefresh
• Customize the refresh icon color

import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener {
	SwipeRefreshLayout cv_refresh;
...
	@Override
    protected void onCreate(Bundle savedInstanceState) {
		cv_refresh = (SwipeRefreshLayout) findViewById(R.id.vv_refresh);
		cv_refresh.setOnRefreshListener(this);
		cv_refresh.setColorSchemeColors(Color.GREEN);
	}
	
    @Override
    public void onRefresh() {
        cv_refresh.setRefreshing(true);
        for (int i=0; i < lv_data.size(); i++) {
            lv_data.get(i).setPrice((int) Math.ceil(Math.random()*500+1000));
        }

        lv_adapter.notifyDataSetChanged();
        // This line is important as it explicitly refreshes only once
        // If "true" it implicitly refreshes forever
        cv_refresh.setRefreshing(false);
    }
}