Understanding USB Communication in Android Apps

UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> connectedDevices = usbManager.getDeviceList();

for (UsbDevice device : connectedDevices.values()) {
    // You can check permissions and more here
}

PendingIntent permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
usbManager.requestPermission(device, permissionIntent);

package com.ayush.gfgapp;

import android.content.Context;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.bottomsheet.BottomSheetDialog;

import java.util.HashMap;

public class MainActivity2 extends AppCompatActivity {

    private Button getDevice;
    private UsbManager usbManager;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        // Initialize button and USB manager
        getDevice = findViewById(R.id.getDevice);
        usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);

        // Set OnClickListener for the button
        getDevice.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Retrieve the list of connected USB devices
                HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
                showDevicesDialog(deviceList);
            }
        });
    }

    private void showDevicesDialog(HashMap<String, UsbDevice> deviceList) {
        if (deviceList.isEmpty()) {
            // Show a toast if no USB devices are found
            Toast.makeText(this, "No USB devices found", Toast.LENGTH_SHORT).show();
        } else {
            // Inflate the bottom sheet layout to display the list of devices
            View bottomSheetView = LayoutInflater.from(this).inflate(R.layout.bottom_sheet_device_list, null);
            LinearLayout devicesLayout = bottomSheetView.findViewById(R.id.devicesLayout);

            for (UsbDevice device : deviceList.values()) {
                // Inflate the layout for each device item
                View deviceItemLayout = LayoutInflater.from(this).inflate(R.layout.device_list_item, null);
                TextView deviceNameTextView = deviceItemLayout.findViewById(R.id.deviceNameTextView);
                TextView vendorIdTextView = deviceItemLayout.findViewById(R.id.vendorIdTextView);
                TextView manufacturerTextView = deviceItemLayout.findViewById(R.id.manufacturerTextView);
                TextView productNameTextView = deviceItemLayout.findViewById(R.id.ProductNameTextView);
                TextView emptyTV = deviceItemLayout.findViewById(R.id.emptyTV);

                // Set information about the device in the corresponding TextViews
                deviceNameTextView.setText("Device Name: " + device.getDeviceName());
                vendorIdTextView.setText("Vendor ID: " + device.getVendorId());
                manufacturerTextView.setText("Manufacturer Name: " + device.getManufacturerName());
                productNameTextView.setText("Product Name: " + device.getProductName());
                emptyTV.setText("Testing:- " + device.getProductId());

                // Add an OnClickListener to handle device selection
                deviceItemLayout.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Toast.makeText(MainActivity2.this, "Device Selected: " + device.getDeviceName() + " (Vendor ID: " + device.getVendorId() + ")", Toast.LENGTH_SHORT).show();
                    }
                });

                  // Add the device item to the layout
                devicesLayout.addView(deviceItemLayout); 
            }

            // Create and display the bottom sheet dialog with the list of devices
            BottomSheetDialog bottomSheetDialog = new BottomSheetDialog(this);
            bottomSheetDialog.setContentView(bottomSheetView);
            bottomSheetDialog.show();
        }
    }
}