Missing Annotations Added, BT UUID issue Fixed

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/bluetooth/BluetoothConnection.java

@@ -10,10 +10,13 @@
 import com.emh.thermalprinter.exceptions.EscPosConnectionException;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.UUID;
 
 public class BluetoothConnection extends DeviceConnection {
 
+    private static final UUID SPP_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
+
     private BluetoothDevice device;
     private BluetoothSocket socket = null;
 
@@ -79,11 +82,16 @@ public BluetoothConnection connect() throws EscPosConnectionException {
     /**
      * Get bluetooth device UUID
      */
-    @SuppressLint("MissingPermission")
     protected UUID getDeviceUUID() {
-        // https://developer.android.com/reference/android/bluetooth/BluetoothDevice - "00001101-0000-1000-8000-00805f9b34fb" SPP UUID
         ParcelUuid[] uuids = device.getUuids();
-        return (uuids != null && uuids.length > 0) ? uuids[0].getUuid() : UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
+        if (uuids != null && uuids.length > 0) {
+            if (Arrays.asList(uuids).contains(new ParcelUuid(BluetoothConnection.SPP_UUID))) {
+                return BluetoothConnection.SPP_UUID;
+            }
+            return uuids[0].getUuid();
+        } else {
+            return BluetoothConnection.SPP_UUID;
+        }
     }
 
     /**

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/bluetooth/BluetoothConnections.java

@@ -1,8 +1,11 @@
 package com.emh.thermalprinter.connection.bluetooth;
 
+import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 
+import androidx.annotation.Nullable;
+
 import java.util.Set;
 
 public class BluetoothConnections {
@@ -19,6 +22,8 @@ public BluetoothConnections() {
      * Get a list of bluetooth devices available.
      * @return Return an array of BluetoothConnection instance
      */
+    @SuppressLint("MissingPermission")
+    @Nullable
     public BluetoothConnection[] getList() {
         if (this.bluetoothAdapter == null) {
             return null;

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/bluetooth/BluetoothPrintersConnections.java

@@ -3,7 +3,7 @@
 import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothClass;
 import android.bluetooth.BluetoothDevice;
-
+import androidx.annotation.Nullable;
 import com.emh.thermalprinter.exceptions.EscPosConnectionException;
 
 public class BluetoothPrintersConnections extends BluetoothConnections {
@@ -13,6 +13,7 @@ public class BluetoothPrintersConnections extends BluetoothConnections {
      *
      * @return a EscPosPrinterCommands instance
      */
+    @Nullable
     public static BluetoothConnection selectFirstPaired() {
         BluetoothPrintersConnections printers = new BluetoothPrintersConnections();
         BluetoothConnection[] bluetoothPrinters = printers.getList();
@@ -36,6 +37,7 @@ public static BluetoothConnection selectFirstPaired() {
      * @return an array of EscPosPrinterCommands
      */
     @SuppressLint("MissingPermission")
+    @Nullable
     public BluetoothConnection[] getList() {
         BluetoothConnection[] bluetoothDevicesList = super.getList();
 

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/tcp/TcpConnection.java

@@ -28,6 +28,9 @@ public TcpConnection(String address, int port) {
     /**
      * Create un instance of TcpConnection.
      *
+     * Overload of the above function TcpConnection()
+     * Include timeout parameter in milliseconds.
+     *
      * @param address IP address of the device
      * @param port    Port of the device
      * @param timeout Timeout in milliseconds to establish a connection

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/usb/UsbConnections.java

@@ -4,6 +4,8 @@
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbManager;
 
+import androidx.annotation.Nullable;
+
 import java.util.Collection;
 
 public class UsbConnections {
@@ -22,6 +24,7 @@ public UsbConnections(Context context) {
      * Get a list of USB devices available.
      * @return Return an array of UsbConnection instance
      */
+    @Nullable
     public UsbConnection[] getList() {
         if (this.usbManager == null) {
             return null;

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/usb/UsbDeviceHelper.java

@@ -5,13 +5,16 @@
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
 
+import androidx.annotation.Nullable;
+
 public class UsbDeviceHelper {
     /**
      * Find the correct USB interface for printing
      *
      * @param usbDevice USB device
      * @return correct USB interface for printing, null if not found
      */
+    @Nullable
     static public UsbInterface findPrinterInterface(UsbDevice usbDevice) {
         if (usbDevice == null) {
             return null;
@@ -32,6 +35,7 @@ static public UsbInterface findPrinterInterface(UsbDevice usbDevice) {
      * @param usbInterface USB interface
      * @return Input endpoint or null if not found
      */
+    @Nullable
     static public UsbEndpoint findEndpointIn(UsbInterface usbInterface) {
         if (usbInterface != null) {
             int endpointsCount = usbInterface.getEndpointCount();

thermalPrinter/src/main/java/com/emh/thermalprinter/connection/usb/UsbPrintersConnections.java

@@ -4,6 +4,8 @@
 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
 
+import androidx.annotation.Nullable;
+
 import com.emh.thermalprinter.exceptions.EscPosConnectionException;
 
 public class UsbPrintersConnections extends UsbConnections {
@@ -22,6 +24,7 @@ public UsbPrintersConnections(Context context) {
      *
      * @return a UsbConnection instance
      */
+    @Nullable
     public static UsbConnection selectFirstConnected(Context context) {
         UsbPrintersConnections printers = new UsbPrintersConnections(context);
         UsbConnection[] bluetoothPrinters = printers.getList();
@@ -39,6 +42,7 @@ public static UsbConnection selectFirstConnected(Context context) {
      *
      * @return an array of UsbConnection
      */
+    @Nullable
     public UsbConnection[] getList() {
         UsbConnection[] usbConnections = super.getList();