MainActivity.java

package com.example.sign_lang_ml;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

public class MainActivity extends AppCompatActivity {

    private final static int MY_PERMISSIONS_REQUEST_CAMERA = 12;
    private final static int MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE = 13;
    Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            if (!ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.CAMERA)) {
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.CAMERA},
                        MY_PERMISSIONS_REQUEST_CAMERA);
            }
        }
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {
            if (!ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE);
            }
        }

        setContentView(R.layout.activity_main);

        // Recognition Button
        btn = findViewById(R.id.recognition);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), recognition.class);
                startActivity(intent);
            }
        });


        // Learning Button
        btn = findViewById(R.id.learning);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), LearningActivity.class);
                startActivity(intent);
            }
        });

        btn = findViewById(R.id.training);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), TrainingActivity.class);
                startActivity(intent);
            }
        });

    }
}