MainActivity

package com.example.chesshelper;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.os.Build;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.DisplayMetrics;
import android.util.Rational;
import android.util.Size;
import android.view.Display;
import android.view.TextureView;
import android.view.View;
import android.view.WindowManager;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

public class MainActivity extends AppCompatActivity {
    private static final int CAMERA_PERMISSION_REQUEST_CODE = 1000;
    private static final int CAMERA_REQUEST_CODE = 1001;
    private ImageIdentifier imageIdentifier;

    ImageView pictureView;
    ListView pictureDetails;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pictureView = findViewById(R.id.capturedImageViewId);
        pictureDetails = findViewById(R.id.listViewId);
        Button capturePictureButtonId = findViewById(R.id.captureImageButtonId);
        Button goBluetooth = findViewById(R.id.bluetoothGoButton);
        try {
            imageIdentifier = new ImageIdentifier(this);
        } catch (IOException e) {
            e.printStackTrace();
        }

        goBluetooth.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent goToBluetoothActivity = new Intent(MainActivity.this, BluetoothActivity.class);
                startActivity(goToBluetoothActivity);
            }
        });

        capturePictureButtonId.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(hasPermission())
                {
                    startCamera();
                }
                else
                {
                    requestPermission();
                }
            }
        });

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(requestCode == CAMERA_PERMISSION_REQUEST_CODE)
        {
            if (hasAllPermissions(grantResults))
            {
                startCamera();
            }
            else
            {
                requestPermission();
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        if(requestCode == CAMERA_REQUEST_CODE)
        {
            Bitmap photo = (Bitmap)Objects.requireNonNull(Objects.requireNonNull(data).getExtras()).get("data");
            pictureView.setImageBitmap(photo);
            List<ImageIdentifier.Recognition> results = imageIdentifier.recognisedImage(photo, 0);
            List<String> finalResults = new ArrayList<>();
            for (ImageIdentifier.Recognition recognition : results)
            {
                finalResults.add(recognition.getName()+"---"+recognition.getConfidence());
            }
            ArrayAdapter<String> predictionAdapter = new ArrayAdapter<>(
                    this,
                    R.layout.support_simple_spinner_dropdown_item, finalResults
            );
            pictureDetails.setAdapter(predictionAdapter);
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    private boolean hasAllPermissions(int[] grantResults) {
        for (int res : grantResults)
        {
            if (res == PackageManager.PERMISSION_DENIED)
            {
                return false;
            }
        }
        return true;
    }

    private void requestPermission() {
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
        {
            if(shouldShowRequestPermissionRationale(Manifest.permission.CAMERA))
            {
                Toast.makeText(this, "You need to give permission for camera!", Toast.LENGTH_LONG).show();
            }
            requestPermissions(new String[]{Manifest.permission.CAMERA}, CAMERA_PERMISSION_REQUEST_CODE);
        }
    }

    private void startCamera() {
        Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(cameraIntent, CAMERA_REQUEST_CODE);
    }

    private boolean hasPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
        {
            return checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED;
        }
        return true;
    }
}